The Kynix Blog

I IntroductionThe LC circuit is a circuit composed of capacitors, inductors, resistors and other components and electronic devices that can generate oscillating current or have a filtering effect, and is also called a resonant circuit, tank circuit, or tuned circuit. The LC circuit formed by connecting the inductor L and the capacitor C is the simplest type of LC circuit. LC circuits are widely used in radio technology and radio and television technology. The LC circuit is indispensable in various radio devices, equipment, measuring instruments, etc. This article will introduce what is the LC circuit, including its basic concepts, basic principles, working process and application circuit diagram. CatalogI IntroductionII The Concept of LC Circuit and ResonanceIII Introduction of Electromagnetic Principle of LC CircuitIV The Operation of LC CircuitV Comparison of Two Types of LC circuits 5.1 Capacitive Feedback Oscillation Circuit 5.2 Inductive Feedback Oscillation CircuitVI Series LC circuit and parallel LC circuit 6.1 Series LC Circuit 6.2 Parallel LC CircuitVII Application of LC Circuit 7.1 Application Note of LC Circuit 7.2 LC Application Circuit DiagramVIII One Quiz Related to LC Oscillator 8.1 Question 8.2 AnswerⅨ FAQII The Concept of LC Circuit and ResonanceIn an AC circuit with a resistor R, an inductor L, and a capacitor C, the phase of the voltage across the circuit and the current in it are generally different. If you adjust the parameters of the circuit components (L or C) or the power frequency, you can make them in the same phase, and the entire circuit appears purely resistive. When the circuit reaches this state, it is called resonance. In the resonant state, the total impedance of the circuit reaches or reaches the extreme value. According to different circuit connections, there are series LC circuit and parallel LC circuit. The essence of resonance is that the electric field energy in the capacitor and the magnetic field energy in the inductance can be converted into each other. The sum of the electric field energy and the magnetic field energy remains constant at all times. The power supply does not need to convert energy back and forth with the capacitor or inductor, but only supplies the energy consumed by the resistance in the circuit.Figure1. What is ResonanceThe LC circuit is used to generate signals of a specific frequency, or to extract signals of a specific frequency only from more complex signals. It is suitable for important components such as oscillation circuits, filter circuits, tuners, and mixers. LC circuit is an ideal model, it ignores the energy dissipation caused by resistance.Figure2. Energy Stored by a CapacitorThe LC circuit uses the energy storage characteristics of capacitors and inductors to alternately transform the two types of electromagnetic energy, that is to say, electrical energy and magnetic energy will have a maximum and minimum value, and there will be oscillation.  However, this is only an ideal situation. In fact, all electronic components will have losses. Energy will either be lost or leak out of the process of conversion between the capacitor and the inductor. The energy will continue to decrease, so the actual LC circuit needs An amplifying element that is either a triode or an integrated op amp and other electrical LC. Using this amplifying element, the continuously consumed oscillation signal is feedback amplified by various signal feedback methods, so as to finally output a signal with stable amplitude and frequency.The frequency calculation formula is f = 1 / [2π√ (LC)],Where f is the frequency and the unit is Hertz (Hz); L is the inductance and the unit is Henry (H); C is the capacitor and the unit is Farad (F).Figure3. Energy Stored by an InductorIII Introduction of Electromagnetic Principle of LC CircuitThe concept of the electromagnetic field is highly generalized. This is a very rich concept. Although it includes the magnetic field of electrostatic field and electric current, the electromagnetic field is not a simple addition of electric field and magnetic field. (1) Several possible situations about the time-varying electric field generated by the magnetic field①A constant magnetic field does not generate an electric field: for example, the original coil of the transformer is always connected to the current power supply. Because the constant current generates a constant magnetic field, no induced current is generated in the secondary coil loop-no electric field that drives charge. ②The changing magnetic field generates an electric field: According to the knowledge of electromagnetic induction, when the magnetic field changes in the closed-loop, an induced current is generated in the loop. Maxwell has a deep insight that the conductor loop is only a tool to reflect the existence of an induced electric field. In essence, as long as there is a magnetic field that changes in space, an electric field will be generated-it is not an electric field generated by a charge. ③ A uniformly changing magnetic field produces a constant electric field: According to Faraday's law of electromagnetic induction, ε = Δф / Δt can be the same as above, and the conclusion can be drawn from Faraday's law of electromagnetic induction.Figure4. Faraday’s Laws of Electromagnetic Induction(2) Regarding the generation of a magnetic field by an electric field, the following will be described in layers according to several possibilities of the time-varying electric field. ①A constant electric field does not generate a magnetic field, for example, the space around a static charge has only an electrostatic field and no magnetic field-a constant electric field does not generate a magnetic field. ②The changing electric field generates a magnetic field. With his extraordinary genius, Maxwell believes that when the capacitor is charged and discharged, the conduction current is interrupted by the capacitor in another way-continuous, he pointed out that the change in the electric field in the capacitor is equivalent to the current-like the conduction current, it can Generate a magnetic field (but does not generate human Joule heat), that is, a changing electric field generates a magnetic field. Connect the parallel-plate capacitor used for large-scale demonstration to the induction coil, and place a free small magnetic needle between the capacitor plates. The deflection of the free small magnetic needle shows that the changing electric field generates a magnetic field. A uniformly changing electric field produces a constant magnetic field: if the charge on the capacitor changes uniformly, the conduction current I = ΔQ / Δt is a steady current, which generates a constant magnetic field in space. When the charge on the capacitor changes uniformly with time, it is necessary to cause a uniform change in the electric field between the plates. The uniformly changed electric field, like a steady conduction current, must generate a constant magnetic field in space.Unevenly changing electric field produces a changing magnetic field using a similar narrative method to draw conclusions.Figure5. Magnetic Field Produced by Electric Current(3) Electromagnetic field According to the reasoning of the above two aspects, the extension points out: In general, the magnetic field generated by an unevenly changing electric field (such as an oscillating current) also changes unevenly, and this magnetic field must also produce an unevenly changing electric field. It can be seen that the changing electric field and magnetic field are always related to each other, forming an inseparable unity, which is the electromagnetic field. Conditions for generating electromagnetic fields:Generated by static charge.Generated by a uniformly changing magnetic field.Produced by steady current.Generated by a uniformly changing electric field. Interdependent non-uniformly changing electric and magnetic fields.Figure6. Electromagnetic FieldsIV The Operation of LC Circuit（1）Charging completed (discharge start): the electric field can reach the maximum, the magnetic field energy is zero, and the induced current i = 0 in the loop. （2）Discharge completed (charging started): the electric field energy is zero, the magnetic field can reach the maximum, and the induced current in the loop reaches the maximum. （3）Charging process: the electric field energy is increasing, the magnetic field energy is decreasing, the current in the loop is decreasing, and the electric capacity on the capacitor is increasing. From the perspective of energy: the magnetic field can be transformed into the electric field. （4）Discharge process: the electric field energy is decreasing, the magnetic field energy is increasing, the current in the loop is increasing, and the amount of electricity on the capacitor is decreasing. From the energy point of view: the electric field can be transformed into the magnetic field. In the process of generating an oscillating current in an oscillating circuit, the charge on the plate of the capacitor, the current through the coil, and the magnetic field and electric field associated with the current and charge all periodically change. This phenomenon is called electromagnetic oscillation.Figure7. Tuned CircuitV Comparison of Two Types of LC Circuits5.1 Capacitive Feedback Oscillation Circuit5.1.1 Circuit CompositionFigure8. Capacitive Feedback Oscillation CircuitIn order to obtain a better output voltage waveform, if the capacitor in the inductive feedback oscillation circuit is replaced with an inductor, the inductor is replaced with a capacitor, and after the conversion, the common terminal of the two capacitors is grounded, and the collector resistance Rc is increased, The capacitor feedback oscillation circuit is obtained, as shown on the right. Because the three terminals of the two capacitors are respectively connected to the three poles of the transistor, it is also called a capacitor three-point circuit. 5.1.2 Working Principle(1) According to the judgment method of the sine wave oscillation circuit, observe the circuit shown in the above figure, which includes four parts: the amplifier circuit, the frequency selection network, the feedback network and the nonlinear element (transistor);(2) The amplifier circuit can work normally;(3) Disconnect the feedback, add the input voltage with frequency f0, and given its polarity, determine the polarity of the feedback voltage obtained from C2 is the same as the input voltage. The polarity is as shown.(4) As long as the circuit parameters are properly selected, the circuit can meet the amplitude condition and produce a sine wave oscillation. 5.1.3 Oscillation Frequency and Starting ConditionsOscillation frequencyFeedback coefficientVibration conditions 5.1.4 Advantages and DisadvantagesThe output voltage waveform of the capacitive feedback oscillation circuit is good, but if the oscillation frequency is adjusted by changing the capacitance method, it will affect the feedback coefficient and the starting condition of the circuit; and if the oscillation frequency is adjusted by changing the inductance method, it is more difficult; Commonly used in the occasion of fixed oscillation frequency. When the adjustable range of the oscillation frequency is not large, the circuit shown in the figure on the right can be used as the frequency selection network.Figure9. Frequency Selective Network with Adjustable Frequency 5.1.5 Measures to Stabilize the Oscillation FrequencyTo increase the frequency of the capacitive feedback oscillation circuit, the capacitance of C1 and C2 and the inductance of L must be reduced. In fact, when C1 and C2 are reduced to a certain degree, the interelectrode capacitance of the transistor and the stray capacitance in the circuit will be included in C1 and C2, thus affecting the oscillation frequency. These capacitors are equivalent to the input capacitance Ci and output capacitance Co of the amplifier circuit. The improved circuit and equivalent appliances are shown in the figure below. Because the inter-electrode capacitance is affected by temperature, the stray capacitance is difficult to determine. In order to stabilize the oscillation frequency, a small-capacity capacitor C3 is connected in series with the inductor branch, and C3 <Oscillation frequencyAlmost has nothing to do with C1 and C2, so does Ci and Co, so the frequency stability is high.Figure10. Improvement of Capacitive Feedback Oscillation Circuit and Equivalent Circuit5.2 Inductive Feedback Oscillation Circuit5.2.1 Circuit CompositionIn order to overcome the disadvantage that the primary coil and the secondary coil of the transformer are not tightly coupled in the feedback oscillation circuit of the transformer, N1 and N2 of the transformer feedback oscillation circuit can be combined into one coil. As shown in the figure, in order to strengthen the resonance effect, the capacitor C is connected across the entire coil to obtain an inductive feedback oscillation circuit.Figure11. Inductive Feedback Oscillation Circuit5.2.2 Working PrincipleObserve the circuit, it contains four parts of the amplifier circuit, frequency selection network, feedback network and nonlinear components (transistors), and the amplifier circuit can work normally.Use the instantaneous polarity method to judge whether the circuit meets the sine wave oscillation phase conditions: ① Disconnect the feedback, add the input voltage with frequency f0, and give its polarity②It is judged that the polarity of the feedback voltage obtained from N2 is the same as the input voltage③ Therefore, the circuit satisfies the phase condition of sine wave oscillation, and the instantaneous polarity of each point is as shown in the above figure.As long as the circuit parameters are properly selected, the circuit can satisfy the amplitude condition and produce a sine wave oscillation.The following figure shows the AC path of the inductive feedback oscillation circuit. The three ends of the primary coil are connected to the three poles of the transistor, so the inductive feedback oscillation circuit is called an inductive three-point circuit.Figure12. AC Path of Inductive Feedback Oscillation Circuit 5.2.3 Oscillation Frequency and Starting ConditionsOscillation frequencyFeedback coefficientVibration conditions 5.2.4 Advantages and DisadvantagesIn the inductive feedback oscillation circuit, the coupling between N2 and N1 is tight, the amplitude is large, and it is easy to oscillate; when C uses a variable capacitor, the oscillation frequency with a wide adjustment range can be obtained, and the highest oscillation frequency can reach tens of MHz. Because the feedback voltage is taken from the inductance, it has a large reactance to high-frequency signals. The feedback signal contains more harmonic components, and the output voltage waveform is not good.VI Series LC Circuit and Parallel LC Circuit6.1 Series LC Circuit6.1.1 ConceptIn the LC circuit, the corresponding frequency value when the inductive reactance and capacitive reactance are equal is called the resonance frequency, that is, XC = XL. As shown in the figure below, the voltage u and the current i in the circuit are in the same phase, and the circuit is resistive. This phenomenon is called series resonance. When the circuit has series resonance, the impedance of the circuit Z = √R ^ 2 + (XC-XL) ^ 2 = R, the total impedance in the circuit is the smallest, and the current will reach the maximum value.Figure13. Series Resonance Frequency 6.1.2 Characteristics of Series LC CircuitWhen the input signal passes through the series LC circuit, according to the characteristics of the inductor and the capacitor, the higher the signal frequency, the larger the impedance of the inductor, and the smaller the impedance of the capacitor. The larger the impedance, the greater the attenuation of the signal. The signal with a higher frequency will be greatly attenuated by the inductor, while the DC signal cannot pass through the capacitor. When the frequency of the input signal bow is equal to the frequency of the LC resonance, the impedance of the LC series circuit is minimum. Signals at this frequency easily output through capacitors and inductors. At this time, the LC series resonant circuit plays the role of frequency selection.Figure14. The Frequency Characteristic for LC Series Resonant Circuits 6.1.3 FormulaWhen series resonance occurs:Inductive reactance XL = capacitive reactance XCSource voltage U = resistance voltage URInductor voltage UL = capacitance voltage UCInductive reactive power QL = capacitive reactive power QCThe total impedance of the circuit ∣Z∣ = resistance RApparent power S = resistance power P6.2 Parallel LC Circuit6.2.1 ConceptThe parallel LC resonance circuit is formed by connecting an inductor and a capacitor in parallel. In a parallel resonant circuit, if the current in the coil is equal to the current in the capacitor, the circuit reaches the state of parallel resonance. In this circuit, except for the LC parallel part, the impedance change of other parts has almost no effect on energy consumption. Therefore, the stability of this circuit is good, and it is used more than series resonance circuits. Parallel resonance is a complete compensation. The power supply does not need to provide reactive power, only the active power required by the resistor. At resonance, the total current of the circuit is the smallest, and the current of the branch is often greater than the total current of the circuit. Therefore, parallel resonance is also called current resonance. When parallel resonance occurs, a large current flows in the inductance and capacitance components, which may cause an accident that the circuit fuse blows or burns electrical equipment; but it is often used to select signals and eliminate interference in radio engineering.Figure15. Parallel LC Circuit6.2.2 Characteristics of Parallel LC Circuit(1) The current and voltage phases are the same, and the circuit is resistive. (2) The series impedance is the smallest and the current is the largest: Z = R, then I = U / R. (3) The voltage at the inductor end and the voltage at the capacitor end are equal in magnitude, opposite in phase, and compensate each other. The voltage at the resistor end is equal to the power supply voltage. (4) The ratio of the inductance (capacitance) terminal voltage to the power supply voltage at resonance is called the quality factor Q, which is also equal to the ratio of inductive reactance (or capacitive reactance) and resistance. When Q >> 1, the voltages on L and C are much larger than the power supply voltage (similar to resonance). This is called series resonance and is often used to amplify the signal voltage; however, series resonance should be avoided in the power supply circuit. VII Application of LC Circuit7.1 Application Note of LC CircuitIn amplifier circuits and other forms of signal processing circuits, parallel LC resonance circuits and series LC resonance circuits are used very frequently.(1) Frequency selection circuit or frequency selection amplifierThe LC circuit can form a frequency selection circuit or a frequency selection amplifier circuit, which is used to select a signal of a desired frequency among a large number of signals for amplification. This circuit is widely used in radio, television and other circuits, as well as in sine wave oscillator circuits.(2) Absorption circuitThe LC circuit can constitute an absorption circuit, which absorbs a signal of a certain frequency among signals of many frequencies, that is, performs attenuation, and removes signals of this frequency from signals of many frequencies.(3) Wave blocking circuitThe LC circuit can form a wave blocking circuit, which prevents signals of a certain frequency from passing through amplifier circuits or other circuits from signals of many frequencies.(4) Phase shift circuitAn LC parallel circuit is used to form a phase shift circuit, and the signal is phase shifted.7.2 LC Application Circuit DiagramLC parallel and series resonant circuits have many changes in application, which is a difficult point in circuit analysis.(1) LC free resonance circuitThe figure below shows the LC free resonance circuit. L in the circuit is an inductor, C is a capacitor, and L and C form a parallel circuit.Figure16. LC Free Resonance Circuit(2) LC parallel resonance phase shift circuitThe following figure shows the phase shift circuit composed of LC parallel resonance circuit. VT1 in the circuit constitutes a primary amplifier; R1 is its base bias resistor; R3 is its emitter resistor; C4 is the emitter bypass capacitor; L1 and C3 constitute an LC parallel resonance circuit, and R2 is the damping resistor of this resonant circuit.Figure17. LC Parallel Resonance Phase Shift CircuitBy adjusting the inductance of L1, the phase of the output signal voltage can be changed to achieve the purpose of phase shift. (3) LC series resonance absorption circuitThe function of the absorption circuit is to remove the signal of a certain frequency in the input signal. The following figure shows the absorption circuit composed of LC series resonant circuit. VT1 in the circuit constitutes a primary amplifier. L1 and C1 form the LC series resonance absorption circuit, and the resonance frequency is connected between the input terminal of VT1 and the ground.Figure18. LC Series Resonance Absorption Circuit (4) Series resonance high-frequency boost circuitThe figure below shows a high-frequency boost circuit composed of LC series circuits. VT1 in the circuit constitutes a first-stage common-emitter amplifier, and L1 and C4 constitute an LC series resonance circuit, which is used to boost high-frequency signals. The resonant frequency of the series resonant circuit of L1 and C4 is higher than the highest frequency of the working signal of this amplifier.Figure19. Series Resonance High Frequency Boost CircuitSince the impedance of the L1 and C4 circuits at resonance is the smallest, and the negative feedback resistance is the smallest after paralleling with the emitter negative feedback resistance R4, the amplification factor at this time is the largest. In this way, the high-frequency signal close to the resonance frequency is improved.For input signals with a frequency much lower than the resonant frequency, the L1 and C4 circuits have no boost effect on them, because the L1 and C4 circuits are in a detuned state and their impedance is very large, and the negative feedback resistance at this time is R4. (5) Input tuning circuitThe radio selects the required radio stations from many radio stations by input tuning circuit. The input tuning circuit is also called antenna tuning circuit, because there is a cash register antenna in this tuning circuit.The following figure shows a typical input tuning circuit. L1 in the circuit is the primary winding of the magnetic rod antenna, L2 is the secondary winding of the magnetic rod antenna; C1-1 is a connection of the double variable capacitor, which is the antenna connection, and C2 is the high-frequency compensation capacitor, which is the trimming capacitor. It is usually attached to a double variable capacitor.Figure20. Input Tuning CircuitThe working principle of input tuned circuit:The primary winding L1 of the magnetic rod antenna, variable capacitor c1-1, and trimmer capacitor C2 constitute LC series resonance circuit. When resonance occurs in the circuit, the energy in L1 is the largest, that is, the voltage amplitude of the signal of the resonant frequency at both ends of L1 is much larger than that of the signal of the non-resonant frequency. In this way, the amplitude of the resonant frequency signal output from the secondary winding L2 through magnetic coupling is the maximum. The following figure shows the practical input tuning circuit.Figure21. Pratical Input Tuning CircuitVIII One Quiz Related to LC Oscillator 8.1 QuestionThe output of a LC oscillator is often fed into a common collector amplifier stage. The reason for this is:a) To provide extra voltage gain.b) To provide negative feedback.c) To reduce loading on the tank circuit.d) To convert the sine wave output to a square wave.8.2 AnswerC Ⅸ FAQ1. What does an LC circuit do?LC circuits are used either for generating signals at a particular frequency, or picking out a signal at a particular frequency from a more complex signal; this function is called a bandpass filter. 2. How do you solve an LC circuit?Begin with Kirchhoff's circuit rule. Take the derivative of each term. The voltage of the battery is constant, so that derivative vanishes. The derivative of charge is current, so that gives us a second-order differential equation. 3. What makes an ideal LC circuit?An LC circuit is an electronic circuit made up of an inductor and a capacitor. ... An ideal LC circuit does not have resistance. At the LC circuit energy saves in the capacitor's electric field. U is energy and q is electric charge. 4. Why do LC circuits resonate?Resonance of a circuit involving capacitors and inductors occurs because the collapsing magnetic field of the inductor generates an electric current in its windings that charges the capacitor, and then the discharging capacitor provides an electric current that builds the magnetic field in the inductor. 5. What is the difference between RC and LC circuits?RC - a resistor and capacitor in series. Exhibits charging behavior with a characteristic time constant with DC voltage source. ... LC (and RLC) - an inductor and capacitor (and resistor) in series. If initially charged, has oscillatory behavior (damped if also has a resistor). 6. What are the different properties of the LC circuit?An LC circuit is a closed loop with just two elements: a capacitor and an inductor. It has a resonance property like mechanical systems such as a pendulum or a mass on a spring: there is a special frequency that it likes to oscillate at, and therefore responds strongly to. 7. Is an LC circuit first order?In electronics, the classic second-order system is the LC circuit. The LC circuit is one of the last two circuits we will solve with the full differential equation treatment. 8. Where is energy stored in the LC circuit?The oscillations of an LC circuit can, thus, be understood as a cyclic interchange between electric energy stored in the capacitor, and magnetic energy stored in the inductor. 9. What is the natural frequency of the LC circuit?The natural frequency of an LC - circuit is 1,25000 cycles per second. 10. What is a parallel LC circuit?Parallel LC Circuit. The Voltage across each terminal of different elements in a parallel circuit is the same. Hence the voltage across the terminals is equal to the voltage across the inductor and the voltage across the capacitor. 

Ⅰ IntroductionWhen connected to a voltage source, capacitors are basic passive devices that can store an electrical charge on their plates. The capacitor, like a miniature rechargeable battery, has the ability or "capacity" to store energy in the form of an electrical charge, producing a potential difference (Static Voltage) across its plates. Capacitors come in a variety of sizes and shapes, ranging from tiny capacitor beads used in resonance circuits to enormous power factor correction capacitors, but they always store charge. this video shows how capacitors work CatalogⅠ IntroductionⅡ Types of Capacitor2.1 Dielectric Capacitor2.2 Variable Capacitor Symbol2.3 Film Capacitor Type2.4 Axial Lead Type2.5 Ceramic Capacitors2.6 Electrolytic Capacitors2.7 Aluminium Electrolytic Capacitors2.8 Tantalum Electrolytic Capacitors2.9 Frequently Asked Questions About Different Types Of CapacitorⅢ The Capacitance of a Capacitor3.1 SI Unit of Capacitance3.2 μF vs. nF vs. pF3.3 Frequently Asked Questions about the Capacitance of a CapacitorⅣ Capacitor Conversion: µF-nF-pF 4.1 Capacitor Conversion Chart4.2 Popular Capacitor Conversions4.3 Frequently Asked Questions about Capacitor ConversionⅤ Capacitor Color Code5.1 Capacitor Colour Code Tables5.2 Color Codes of Different Capacitors5.3 Frequently Asked Questions about Capacitor Color CodeⅥ Capacitor Code6.1 Types of Capacitor Code6.2 Frequently Asked Questions about Capacitor CodeⅦ Capacitor Code Calculator7.1 Capacitor Safety Discharge Calculator Tool7.2 Series and Parallel Capacitance Calculator Ⅱ Types of CapacitorFrom very small delicate trimming capacitors used in oscillator or radio circuits to enormous power metal-can type capacitors used in high voltage power correction and smoothing circuits, capacitors are available. The dielectric used between the plates is commonly used to make comparisons between different types of capacitors. There are variable varieties of capacitors, just like resistors, that allow us to adjust their capacitance value for use in radio or "frequency tuning" circuits. Metallic foil is interwoven with thin sheets of either paraffin-impregnated paper or Mylar as the dielectric material in commercial capacitors. Because the metal foil plates are rolled up into a cylinder to produce a compact box with the insulating dielectric material sandwiched in between, some capacitors resemble tubes. Ceramic materials are frequently used to make small capacitors, which are subsequently sealed with epoxy resin. Capacitors play a crucial role in electronic circuits in any case, therefore here are a few of the most "common" capacitor types available. 2.1 Dielectric CapacitorWhen a constant variation in capacitance is necessary for tuning transmitters, receivers, and transistor radios, dielectric capacitors are normally of the variable variety. Multi-plate air-spaced variable dielectric capacitors have a set of fixed plates (the stator vanes) and a set of movable plates (the rotor vanes) that move in between the fixed plates. The overall capacitance value is determined by the position of the moving plates concerning the fixed plates. When the two sets of plates have entirely meshed together, the capacitance is usually at its highest. With breakdown voltages in the thousands of volts, high voltage tuning capacitors have relatively large spacings or air gaps between the plates. 2.2 Variable Capacitor SymbolTrimmers are pre-set type variable capacitors that are available in addition to continuously variable varieties. These are typically small devices that may be modified or "pre-set" to a specific capacitance value with a small screwdriver, and are available in very low capacitances of 500pF or less, and are non-polarized. variable capacitor symbol 2.4 Axial Lead TypeLong thin strips of thin metal foil with the dielectric material sandwiched between them are twisted into a tight roll and then sealed in paper or metal tubes for film and foil capacitors. To lessen the possibility of tears or punctures in the film, these film types require a significantly thicker dielectric film and are thus better suited to lower capacitance values and bigger case sizes. axial-lead-type Metalized foil capacitors have the conductive film metalized sprayed directly onto each side of the dielectric, giving the capacitor self-healing capabilities and allowing thinner dielectric films to be used. For a given capacitance, this enables for larger capacitance values and smaller case sizes. Film and foil capacitors are typically employed in situations that require more power and precision. 2.5 Ceramic CapacitorsCeramic capacitors, also known as Disc capacitors, are created by coating two sides of tiny porcelain or ceramic disc with silver and stacking them together to form a capacitor. A single ceramic disc of roughly 3-6mm is utilized for very low capacitance values. Ceramic capacitors have a high dielectric constant (High-K) and are available in tiny physical sizes, allowing for relatively high capacitances. ceramic capacitor Because they are non-polarized and exhibit huge non-linear changes in capacitance with temperature, they are employed as de-coupling or by-pass capacitors. Ceramic capacitors range in size from a few picofarads to one or two microfarads, but their voltage ratings are often modest. A three-digit code is usually inscribed on the body of ceramic capacitors to identify their capacitance value in pico-farads. The first two digits usually represent the capacitor's value, while the third digit represents the number of zeros to be added. A ceramic disc capacitor marked 103, for example, would indicate 10 and 3 zeros in pico-farads, which is equal to 10,000 pF or 10nF. The numerals 104, for example, represent 10 and 4 zeros in pico-farads, which is comparable to 100,000 pF or 100nF, and so on. The digits 154 on the ceramic capacitor image above represent 15 and 4 zeros in pico-farads, which is comparable to 150,000 pF, 150nF, or 0.15F. To signify their tolerance value, letter codes are occasionally employed, such as J = 5%, K = 10%, M = 20%, and so on. 2.6 Electrolytic CapacitorsWhen very large capacitance values are required, electrolytic capacitors are typically utilized. Instead of employing a very thin metallic film layer for one of the electrodes, a semi-liquid electrolyte solution in the form of jelly or paste is employed (usually the cathode). The dielectric is a very thin layer of oxide that is produced electrochemically in the manufacturing process and has a thickness of fewer than ten microns. Because the insulating layer is so thin, capacitors with a big capacitance value can be made in a small physical size because the distance between the plates, d, is so short. electrolytic capacitor The majority of electrolytic capacitors are polarized, which means that the DC voltage applied to the capacitor terminals must be of the correct polarity, i.e. positive to the positive terminal and negative to the negative terminal, or the insulating oxide layer will be broken down and permanent damage may result. The polarity of all polarized electrolytic capacitors is indicated with a negative sign to signify the negative terminal, which must be followed. Due to their huge capacitance and small size, electrolytic capacitors are commonly employed in DC power supply circuits to help reduce ripple voltage or for coupling and decoupling applications. Electrolytic capacitors have a low voltage rating, which means that they can't be utilized on AC supply because of their polarization. Aluminium Electrolytic Capacitors and Tantalum Electrolytic Capacitors are the two most common types of electrolytes. 2.7 Aluminium Electrolytic CapacitorsThe plain foil type and the etched foil type are the two varieties of Aluminum Electrolytic capacitors. These capacitors have extremely high capacitance values for their size due to the thickness of the aluminum oxide coating and the high breakdown voltage.aluminium electrolytic capacitor A DC current is used to anodize the capacitor's foil plates. The polarity of the plate material is established during the anodizing process, which defines which side of the plate is positive and which side is negative. The aluminum oxide on the anode and cathode foils has been chemically etched to increase surface area and permittivity, which makes the etched foil type different from the plain foil type. This results in a smaller capacitor than a normal foil type of comparable value, but it has the disadvantage of not being able to handle strong DC currents. Their tolerance range is also fairly high, reaching up to 20%. Capacitance values for aluminum electrolytic capacitors typically range from 1uF to 47,000uF. Plain foil electrolytes are better suited as smoothing capacitors in power supply, while etched foil electrolytes are best employed in the coupling, DC blocking, and by-pass circuits. However, because aluminum electrolytes are “polarized” devices, inverting the applied voltage on the leads will damage the insulating layer within the capacitor, as well as the capacitor itself. The capacitor's electrolyte, on the other hand, aids in the healing of a damaged plate if the damage is minor. The electrolyte has the power to re-anodize the foil plate since it can self-heal a damaged plate. The electrolyte can remove the oxide layer from the foil if the anodizing process is reversed, as it would if the capacitor was connected with reverse polarity. Because the electrolyte can conduct electricity, if the aluminum oxide layer is removed or destroyed, current can flow from one plate to the other, causing the capacitor to fail, "so be alert." 2.8 Tantalum Electrolytic CapacitorsTantalum Electrolytic Capacitors and Tantalum Beads come in both wet (foil) and dry (solid) electrolytic varieties, with dry tantalum being the most prevalent. Solid tantalum capacitors have a second terminal of manganese dioxide and are physically smaller than analogous aluminum capacitors. Tantalum oxide's dielectric characteristics are superior to those of aluminum oxide, resulting in reduced leakage currents and greater capacitance stability, making it ideal for blocking, by-passing, decoupling, filtering, and timing applications. Tantalum capacitors, although being polarized, can withstand being linked to a reverse voltage considerably better than aluminum capacitors, but they are rated at much lower operating voltages. Solid tantalum capacitors are commonly employed in circuits with low AC voltages compared to DC voltages. Some tantalum capacitors, on the other hand, comprise two capacitors in one, connected negative-to-negative to make a “non-polarized” capacitor for use in low voltage AC circuits. The positive lead of a tantalum bead capacitor is usually identifiable by a polarity mark on the capacitor body, which has an oval geometrical shape. Capacitance values typically vary from 47nF to 470F. 2.9 Frequently Asked Questions About Different Types Of Capacitor1. Which type of capacitor is best?Class 1 ceramic capacitors offer the highest stability and lowest losses. They have high tolerance and accuracy and are more stable with changes in voltage and temperature. Class 1 capacitors are suitable for use as oscillators, filters, and demanding audio applications. 2. Does the type of capacitor matter?Yes, the type of capacitor can matter. Different types of capacitor have different properties. Some of the properties that vary between capacitor types: polarized vs unpolarized. 3. Are all capacitors the same?Not all capacitors are created equal. Each capacitor is built to have a specific amount of capacitance. The capacitance of a capacitor tells you how much charge it can store, more capacitance means more capacity to store charge. 4. Which type of capacitor is known as Polarised capacitor?Electrolytic Capacitors. The Electrolytic Capacitors are the capacitors which indicate by the name that some electrolyte is used in it. They are polarized capacitors which have anode + and cathode − with particular polarities. A metal on which insulating oxide layer forms by anodizing is called as an Anode. 5.Which capacitors are not polarized?Ceramic, mica and some electrolytic capacitors are non-polarized. You'll also sometimes hear people call them "bipolar" capacitors. A polarized ("polar") capacitor is a type of capacitor that have implicit polarity -- it can only be connected one way in a circuit. Ⅲ The Capacitance of a CapacitorThe Farad (abbreviated to F) is the unit of capacitance and is named after the British physicist Michael Faraday. Capacitance is the electrical property of a capacitor and is the measure of a capacitor's ability to store an electrical charge onto its two plates. When a charge of One Coulomb is stored on the plates by a voltage of One volt, a capacitor has a capacitance of One Farad. It's worth noting that capacitance, or C, is always positive and has no negative units. However, because the Farad is a relatively big unit of measurement on its own, sub-multiples such as micro-farads, nano-farads, and pico-farads are commonly used. 3.1 SI Unit of CapacitanceCapacitors are a common type of electrical component, and their values are usually stated in microfarads, F (or uF if a micro character is not available), nanofarads, nF, or picofarads, pF. Microfarad (μF)  1μF = 1/1,000,000 = 0.000001 = 10-6 FNanofarad (nF)  1nF = 1/1,000,000,000 = 0.000000001 = 10-9 FPicofarad (pF) 1pF=1/1,000,000,000,000 = 0.000000000001 = 10-12 F 3.2 μF vs. nF vs. pFAlthough most current circuits and component descriptions use the nomenclature F, nF, and pF to specify capacitor values, older circuit designs, circuit descriptions, and even the components themselves may employ a variety of non-standard acronyms that aren't always evident. The following are the main changes for the various capacitance sub-multiples: Micro-Farad, µF: Larger value capacitors, such as electrolytic capacitors, tantalum capacitors, and even some paper capacitors measured in micro-Farads, may have been labeled with uF, mfd, MFD, MF, or UF. All of these terms refer to the value in µF. Electrolytic and tantalum capacitors are commonly connected with this nomenclature. Nano-Farad, nF: Because nF or nano-Farads nomenclature was not frequently used prior to terminology standardization, this submultiple lacked a variety of abbreviations. The term nanofarad has gained in popularity in recent years, while it is still not widely used in some countries, with values given in huge numbers of picofarads, such as 1000pF for 1 nF, or fractions of a microfarad, such as 0.001 µF for a nanofarad. Ceramic capacitors, metalized film capacitors, including surface mount multilayer ceramic capacitors, and even some modern silver mica capacitors all use this terminology. Pico-Farad, pF: The value in picoFarads, pF, was again indicated using a variety of acronyms.  MicroromicroFarads, mmfd, MMFD, uff, µµFwere among the terms used. All of these numbers are in pF. Picofarad capacitor values are commonly employed in radio frequency, RF circuits, and equipment. As a result, this nomenclature is most commonly associated with ceramic capacitors, however, it is also applied to silver mica capacitors and some film capacitors. The conversion of values from one submultiple to the next has been aided by the standardization of terminology. It has resulted in a significant reduction in the potential for misunderstanding. Converting from µF to nF and pF is simpler. This is important when a capacitor value is listed in one way on a circuit diagram and another way on a list of electronic components distributors. Because different electrical component manufacturers label components differently, the capacitance conversion table is highly useful. For example, some manufacturers label their equivalent capacitors as a fraction of a microfarad, while others label them as a fraction of a nanofarad, and so on. Electrical component wholesalers and retailers will prefer to adopt the manufacturer's nomenclature. Similarly, circuit diagrams may use different symbols to represent components to maintain commonality, etc. As a result, being able to convert between picofarads, nanofarads, and microfarads, as well as vice versa, is beneficial. When the bill of materials or parts list for the circuit has values expressed in microfarads, µF, and picofarads, pF, this can aid identify components labeled in nanofarad values. It is generally useful to be able to utilize a capacitance conversion calculator like the one above, but it is also important to be familiar with the conversions and popular equivalents, such as 1000pF = nanofarad and 100nF = 0.1µF. These conversions become second nature while working with electrical components and designing electronic circuits, but the capacitance conversion tables and calculators can still be quite useful. Capacitors, as well as other electronic components like inductors, benefit from these conversions. 3.3 Frequently Asked Questions about the Capacitance of a Capacitor1. What is capacitance in simple terms?Capacitance is the ability of a system of electrical conductors and insulators to store electric charge when a potential difference exists between the conductors. Capacitance is expressed as a ratio of the electrical charge stored to the voltage across the conductors. 2.What is C in capacitance?The capacitance C is the ratio of the amount of charge q on either conductor to the potential difference V between the conductors, or simply C = q/V. 3.What is difference between capacitor and capacitance?Capacitance is nothing but the ability of a capacitor to store the energy in form of electric charge. In other words, the capacitance is the storing ability of a capacitor. It is measured in farads. 4.What is the formula of capacitor?The governing equation for capacitor design is: C = εA/d, In this equation, C is capacitance; ε is permittivity, a term for how well dielectric material stores an electric field; A is the parallel plate area; and d is the distance between the two conductive plates. 5.What four factors affect capacitance?The capacitance of a capacitor is affected by the area of the plates, the distance between the plates, and the ability of the dielectric to support electrostatic forces. Ⅳ Capacitor Conversion: µF-nF-pF  The use of the nanofarad (nF) is less common in some fields, with values stated in fractions of a µF and huge multiples of picofarads (pF). When components marked in nanofarad are available, it may be necessary to convert to nanofards, nF in these circumstances. When a circuit diagram or electronic components list mentions the value in picofarads, for example, and listings for an electronic component distributor or electronic components store state it in another way, it can be confusing. Capacitor values can be in the 109 range or even higher, thanks to the introduction of supercapacitors. The common prefixes pico (10-12), nano (10-9), and micro (10-6) are often used to avoid misunderstanding with high numbers of zeros connected to the values of different capacitors. When converting between them, a capacitor conversion chart or capacitor conversion table for the various capacitor values can be useful. Another requirement for capacitance conversion is that the actual capacitance value is reported in picofarads in some capacitor marking systems, therefore the value must be converted to the more common nanofarads or microfarads. 4.1 Capacitor Conversion ChartMicrofarads ( µF)Nanofarads(nF)Picofarads(pF)0.0000010.00110.000010.01100.00010.11000.001110000.0110100000.11001000001100010000001010000100000001001000001000000004.2 Popular Capacitor ConversionsCapacitor values can be written in a few different ways. A ceramic capacitor, for example, is frequently assigned a value of 100nF. It is often interesting to realize that this is 0.1µF when utilized in circuits with electrolytic capacitors. These handy conversions can aid in the design, construction, and maintenance of circuits. When building circuits or employing capacitors in any fashion, keeping these capacitor conversions in mind when values migrate from picofarads to nanofarads and then nanofarads to microfarads is typically beneficial. A more comprehensive table of conversion factors to convert between the different values, nF to pF, µF to nF etc is given below.Table of Conversion Factors to Convert between µF,nF and pF convertmultiply by:pF     to     nF1 x 10-3pF     to     µF1 x 10-6nF     to     pF1 x 103nF     to     µF1 x 10-3µF     to     pF1 x 106µF     to     nF1 x 103 4.3 Frequently Asked Questions about Capacitor Conversion1. Can I replace a capacitor with a higher uF?An electric motor start capacitors can be replaced with a micro-farad or UF equal to or up to 20% higher UF than the original capacitor serving the motor. 2.What happens if I use a higher uF capacitor?The higher the number of micro-farads, the more energy the capacitor can hold. In theory, if a device has a high uF, it will last longer in a power outage.3.What happens if you use the wrong size capacitor?If the wrong run capacitor is installed, the motor will not have an even magnetic field. This will cause the rotor to hesitate at those spots that are uneven. This hesitation will cause the motor to become noisy, increase energy consumption, cause performance to drop, and cause the motor to overheat. 4.Can I replace a capacitor with a lower capacitance?Yes, it's possible given the necessary skills and tools. Yes, it's safe. The only rating that matters for safety is the rated voltage: if you put a higher voltage than the maximum you might see your cap explode. 5.Can I use a run capacitor in place of a start capacitor?The capacitance and voltage ratings would have to match the original start capacitor specification. A start capacitor can never be used as a run capacitor, because it cannot not handle current continuously. Ⅴ Capacitor Color Code5.1 Capacitor Colour Code TablesWhen the capacitance value is a decimal value, problems with the marking of the "Decimal Point" arise since it is easily overlooked, leading to a misunderstanding of the real capacitance value. Instead of the decimal point, letters like p (pico) or n (nano) are used to indicate the position and weight of the number. A capacitor might be labeled as n47 = 0.47nF, 4n7 = 4.7nF, or 47n = 47nF, for example. Also, capacitors are occasionally labeled with the capital letter K to indicate a value of one thousand pico-Farads, thus a capacitor marked 100K would be 100 x 1000pF or 100nF. An International color-coding scheme was devised many years ago as a simple manner of identifying capacitor values and tolerances to reduce the confusion regarding letters, numbers, and decimal points. The Capacitor Colour Code system, which consists of colored bands (in spectral order) and whose meanings are given below, is a system that consists of colored bands (in spectral order). Band ColourDigit ADigit BMultiplier DTolerance (T) > 10pfTolerance (T) < 10pfTemperature Coefficient (TC)Black00x1± 20%± 2.0pF Brown11x10± 1%± 0.1pF-33×10-6Red22x100± 2%± 0.25pF-75×10-6Orange33x1,000± 3% -150×10-6Yellow44x10,000± 4% -220×10-6Green55x100,000± 5%± 0.5pF-330×10-6Blue66x1,000,000  -470×10-6Violet77   -750×10-6Grey88x0.01+80%,-20%  White99x0.1± 10%± 1.0pF Gold  x0.1± 5%  Silver  x0.01± 10%  Capacitor Colour Code Table Band ColourVoltage Rating (V) Type JType KType LType MType NBlack4100 1010Brown62001001.6 Red10300250435Orange15400 40 Yellow205004006.36Green25600 1615Blue35700630 20Violet50800   Grey 900 2525White31000 2.53Gold 2000   Silver     Capacitor Voltage Colour Code Table Capacitor Voltage ReferenceType J–  Dipped Tantalum Capacitors.Type K–  Mica Capacitors.Type L–  Polyester/Polystyrene Capacitors.Type M–  Electrolytic 4 Band Capacitors.Type N–  Electrolytic 3 Band Capacitors. 5.2 Color Codes of Different Capacitors 1.Metalised Polyester Capacitor  2. Disc & Ceramic Capacitor  For many years, unpolarized polyester and mica molded capacitors were coded using the Capacitor Colour Code system. Although this color coding method is no longer in use, many “old” capacitors can still be found. Small capacitors, such as film or disk kinds, now comply with the BS1852 Standard and its new replacement, BS EN 60062, which replaces the colors with a letter or number coding system. 5.3 Frequently Asked Questions about Capacitor Color Code1. What do capacitor colors mean?All the color bands painted on the capacitors body are used to indicate the capacitance value and capacitance tolerance. The color codes used to represent the capacitance values and capacitance tolerance is similar to that used to represent resistance values and resistance tolerance. 2.How do you read a capacitor code?If you have a capacitor that has nothing other than a three-digit number printed on it, the third digit represents the number of zeros to add to the end of the first two digits. The resulting number is the capacitance in pF. For example, 101 represents 100 pF: the digits 10 followed by one additional zero. 3.Which type of capacitor is available in color code?A color code was used on polyester capacitors for many years. It is now obsolete, but of course there are many still around. The colors should be read like the resistor code, the top three color bands giving the value in pF. Ignore the 4th band (tolerance) and 5th band (voltage rating). 4.Are capacitors color coded?The capacitors use a capacitor color code similar to the resistors color code (3, 4 or 5 bands). The first two colors indicate significant digits of the value of the capacity (in pF), the next colour is the corresponding power of 10, the other two colors are optional and indicate tolerance and maximum voltage. Ⅵ Capacitor Code6.1 Types of Capacitor CodeFor example, a capacitor labeled 474J should be read as 47 times the value listed in Table 1 corresponding to the third number, in this case, 10000: 47 * 10000 = 470000 pF = 470 nF = 0.47µF, with the J indicating a 5% tolerance. If a temperature coefficient is present, the second letter will be it. You'll rapidly learn to tell whether a capacitor's value is expressed in pF, nF, or µF based on its size and kind. The capacitance of a capacitor designated 2A474J is encoded as mentioned above; the two initial signs are the voltage rating, which can be decoded from table 2 below. According to the EIA standard, 2A is a 100V DC rating. Some capacitors are only marked 0.1 or 0.01, mostly in these cases the values are given in µF. Some small capacitance capacitors contain an R between the numbers, such as 3R9, which indicates that the value is less than 10pF and has nothing to do with resistance. 3R9 has a 3.9pF value. Table 1 – Capacitor codes with letters and tolerances3rd numberMultiply withLetterTolerance01D0.5pF110F1%2100G2%31,000H3%410,000J5%5100,000K10%61,000,000M20%7Not usedM20%80.01P+100%/-0%90.1Z+80%/-20% Table 2A – Electronic Industries Alliance (EIA) – DC voltage code table0E = 2.5 VDC2A = 100 VDC3A = 1 kVDC0G = 4.0 VDC2Q = 110 VDC3L = 1.2 kVDC0L = 5.5 VDC2B = 125 VDC3B = 1.25 kVDC0J = 6.3 VDC2C = 160 VDC3N = 1.5 kVDC1A = 10 VDC2Z = 180 VDC3C = 1.6 kVDC1C = 16 VDC2D = 200 VDC3D = 2 kVDC1D = 20 VDC2P = 220 VDC3E = 2.5 kVDC1E = 25 VDC2E = 250 VDC3F = 3 kVDC1V = 35 VDC2F = 315 VDC3G = 4 kVDC1G = 40 VDC2V = 350 VDC3H = 5 kVDC1H = 50 VDC2G = 400 VDC3I = 6 kVDC1J = 63 VDC2W = 450 VDC3J = 6.3 kVDC1M = 70 VDC2J = 630 VDC3U = 7.5 kVDC1U = 75 VDC2I = 650 VDC3K = 8 kVDC1K = 80 VDC2K = 800 VDC  Table 2B – Electronic Industries Alliance (EIA) – AC voltage code table2Q = 125 VAC2T = 250 VAC2S = 275 VAC2X = 280 VAC2F = 300 VACI0 = 305 VACL0 = 350 VAC2Y = 400 VACP0 = 440 VACQ0 = 450 VACV0 = 630 VAC  Table 3 – Capacitor code tablepico-farad (pF)nano-farad (nF)micro-farad (µF) Capacitor Code1 pF capacitor code0.001 nF capacitor code0.000001 µF capacitor code101.5 pF capacitor code0.0015 nF capacitor code0.0000015 µF capacitor code1R52.2 pF capacitor code0.0022 nF capacitor code0.0000022 µF capacitor code2R23.3 pF capacitor code0.0033 nF capacitor code0.0000033 µF capacitor code3R33.4 pF capacitor code0.0039 nF capacitor code0.0000039 µF capacitor code3R93.5 pF capacitor code0.0047 nF capacitor code0.0000047 µF capacitor code4R75.6 pF capacitor code0.0056 nF capacitor code0.0000056 µF capacitor code5R66.8 pF capacitor code0.0068 nF capacitor code0.0000068 µF capacitor code6R88.2 pF capacitor code0.0082 nF capacitor code0.0000082 µF capacitor code8R210 pF capacitor code0.01 nF capacitor code0.00001 µF capacitor code10015 pF capacitor code0.015 nF capacitor code0.000015 µF capacitor code15022 pF capacitor code0.022 nF capacitor code0.000022 µF capacitor code22033 pF capacitor code0.033 nF capacitor code0.000033 µF capacitor code33047 pF capacitor code0.047 nF capacitor code0.000047µF capacitor code47056 pF capacitor code0.056 nF capacitor code0.000056 µF capacitor code56068 pF capacitor code0.068 nF capacitor code0.000068 µF capacitor code68082 pF capacitor code0.082 nF capacitor code0.000082 µF capacitor code820100 pF capacitor code0.1 nF capacitor code0.0001 µF capacitor code101120 pF capacitor code0.12 nF capacitor code0.00012 µF capacitor code121130 pF capacitor code0.13 nF capacitor code0.00013µF capacitor code131150 pF capacitor code0.15 nF capacitor code0.00015 µF capacitor code151180 pF capacitor code0.18 nF capacitor code0.00018 µF capacitor code181220 pF capacitor code0.22 nF capacitor code0.00022 µF capacitor code221330 pF capacitor code0.33 nF capacitor code0.00033 µF capacitor code331470 pF capacitor code0.47 nF capacitor code0.00047 µF capacitor code471560 pF capacitor code0.56 nF capacitor code0.00056 µF capacitor code561680 pF capacitor code0.68 nF capacitor code0.00068 µF capacitor code681750 pF capacitor code0.75 nF capacitor code0.00075 µF capacitor code751820 pF capacitor code0.82 nF capacitor code0.00082 µF capacitor code8211000 pF capacitor code1 / 1n / 1 nF capacitor code0.001 µF capacitor code1021500 pF capacitor code1.5 / 1n5 / 1.5 nF capacitor code0.0015 µF capacitor code1522000 pF capacitor code2 / 2n / 2 nF capacitor code0.002 µF capacitor code2022200 pF capacitor code2.2 / 2n2 / 2.2 nF capacitor code0.0022 µF capacitor code2223300 pF capacitor code3.3 / 3n3 / 3.3 nF capacitor code0.0033 µF capacitor code3324700 pF capacitor code4.7 / 4n7 / 4.7 nF capacitor code0.0047 µF capacitor code4725000 pF capacitor code5 / 5n / 5 nF capacitor code0.005 µF capacitor code5025600 pF capacitor code5.6 / 5n6 / 5.6 nF capacitor code0.0056 µF capacitor code5626800 pF capacitor code6.8 / 6n8 / 6.8 nF capacitor code0.0068 µF capacitor code68210000 pF capacitor code10 / 10n / 10 nF capacitor code0.01 µF capacitor code10315000 pF capacitor code15 / 15n / 15 nF capacitor code0.015 µF capacitor code15322000 pF capacitor code22 / 22n / 22 nF capacitor code0.022 µF capacitor code22333000 pF capacitor code33 / 33n / 33 nF capacitor code0.033 µF capacitor code33347000 pF capacitor code47 / 47n / 47 nF capacitor code0.047 µF capacitor code47368000 pF capacitor code68 / 68n / 68 nF capacitor code0.068 µF capacitor code683100000 pF capacitor code100 / 100n / 100 nF capacitor code0.1 µF capacitor code104150000 pF capacitor code150 / 150n / 150 nF capacitor code0.15 µF capacitor code154200000 pF capacitor code200 / 200n / 200 nF capacitor code0.20 µF capacitor code204220000 pF capacitor code220 / 220n / 220 nF capacitor code0.22 µF capacitor code224330000 pF capacitor code330 / 330n / 330nF capacitor code0.33 µF capacitor code334470000 pF capacitor code470 / 470n / 470nF capacitor code0.47 µF capacitor code474680000 pF capacitor code680 nF capacitor code0.68 µF capacitor code6841000000 pF capacitor code1000 nF capacitor code1.0 µF capacitor code1051500000 pF capacitor code1500 nF capacitor code1.5 µF capacitor code1552000000 pF capacitor code2000 nF capacitor code2.0 µF capacitor code2052200000 pF capacitor code2200 nF capacitor code2.2 µF capacitor code2253300000 pF capacitor code3300 nF capacitor code3.3 µF capacitor code3354700000 pF capacitor code4700 nF capacitor code4.7 µF capacitor code4756800000 pF capacitor code6800 nF capacitor code6.8 µF capacitor code68510000000 pF capacitor code10000 nF capacitor code10 µF capacitor code10615000000 pF capacitor code15000 nF capacitor code15 µF capacitor code15620000000 pF capacitor code20000 nF capacitor code20 µF capacitor code20622000000 pF capacitor code22000 nF capacitor code22 µF capacitor code22633000000 pF capacitor code33000 nF capacitor code33 µF capacitor code33647000000 pF capacitor code47000 nF capacitor code47 µF capacitor code47668000000 pF capacitor code68000 nF capacitor code68 µF capacitor code686100000000 pF capacitor code100000 nF capacitor code100 µF capacitor code107330000000 pF capacitor code330000 nF capacitor code330 µF capacitor code337470000000 pF capacitor code470000 nF capacitor code470 µF capacitor code477680000000 pF capacitor code680000 nF capacitor code680 µF capacitor code6871000000000 pF capacitor code1000000 nF capacitor code1000 µF capacitor code1086.2 Frequently Asked Questions about Capacitor Code1. What is the code of a capacitor?Generally, the actual values of Capacitance, Voltage or Tolerance are marked onto the body of the capacitors in the form of alphanumeric characters. For example, a capacitor can be labeled as, n47 = 0.47nF, 4n7 = 4.7nF or 47n = 47nF and so on. 2.What does the numbers on a capacitor mean?The first two numbers represent the value in picofarads, while the third number is the number of zeroes to be added to the first two. For example, a 4.7 μF capacitor with a voltage rating of 25 volts would bear the marking E476. 3.What is the value of a capacitor?Capacitor values can be of over 109 range, and even more as super capacitors are now being used. To prevent confusion with large numbers of zeros attached to the values of the different capacitors the common prefixes pico (10 -12 ), nano (10 -9) and micro (10 -6) are widely used. 4.How can you determine the value of a capacitor?The value of capacitors can be determined by several ways depending up on the type of capacitor like electrolytic, disc, film capacitors, etc. These methods include value or number printed on the body of the capacitor or color coding of the capacitor. 5.How can I determine the capacitance of an unknown capacitor?To determine an unknown capacitance using an oscilloscope , a dc power source such as a 9-V battery, a known resistance, a switch and the capacitor are all connected in series. An oscilloscope probe tip and ground lead are connected across the capacitor. Additionally, you need a short wire jumper to shunt across the capacitor. Ⅶ Capacitor Code Calculator7.1 Capacitor Safety Discharge Calculator ToolThis Capacitor Safety Discharge Calculator helps to determine the discharge rate of a capacitor at known capacitance and charge through a fixed-value resistor. Enter the initial voltage, time, resistance, and capacitance into the calculator. The calculator will display the total voltage discharged and remaining. Many factors need to be considered when choosing a discharge resistor. Safety standards require the voltage across a capacitor to reach a safe voltage before a person is able to touch it. In the USA, standards such as UL, OSHA, NTA, ETL, MET, etc. will have the requirements available for the needs of your product.Capacitor Safety Discharge Calculator Tool 7.2 Series and Parallel Capacitance CalculatorThis tool calculates the overall capacitance value for multiple capacitors connected either in series or in parallel.Series and Parallel Capacitance Calculator 

IntroductionRLC circuit is a circuit structure composed of resistance (R), inductance (L), and capacitance (C). The LC circuit is a simple example. RLC circuits are also called second-order circuits. The voltage or current in the circuit is the solution of a second-order differential equation, and its coefficients are determined by the circuit structure.If the circuit components are regarded as linear components, an RLC circuit can be regarded as an electronic harmonic oscillator.The natural frequency of this circuit is generally expressed as: (unit: Hz)RLC circuits are often used as band-pass filters or band-stop filters, and the Q factor can be obtained by the following formula:There are generally two types of RLC circuit composition: series and parallel.The animation above demonstrates the operation of the LC circuit (RLC circuit without resistors). The charge is transferred back and forth between the capacitor plate and the inductor. The energy oscillates back and forth between the electric field (E) of the capacitor and the magnetic field (B) of the inductor. The RLC circuit works similarly. The difference is that the oscillating current decays to zero over time due to the resistance in the circuit.CatalogIntroductionCatalogI RLC Series Circuit 1.1 What is Series RLC Circuit? 1.2 What is Transient Response of RLC Circuit? 1.3 Laplacian Domain 1.4 RLC Series Resonance Formula   1.5 Phasor Diagram of RLC Series CircuitII RLC Parallel CircuitIII The Difference Between Series Resonant Circuit and Parallel Resonant Circuit 3.1 Series Resonance 3.2 Parallel ResonanceIV Application of RLC Circuit Resonance 4.1 Application of Series Resonance Circuit 4.2 Application of Parallel Resonance CircuitV Frequently Asked Questions about RLC CircuitI RLC Series Circuit1.1 What is Series RLC Circuit?Figure1. RLC Series CircuitV-supply voltageI-circuit currentR-resistanceL-InductanceC-capacitanceIn this circuit, all three elements are connected in series with the voltage. The main differential equations can be obtained by substituting the constitutive equations of the three elements into Kirchhoff's voltage law (KVL). From Kirchhoff's voltage law:are the voltages across R, L, and C respectively, and V(t) is the voltage of the power supply that changes with time. Substituting the constitutive equation to get:In the case of a constant supply voltage, take the derivative of the above formula and divide by L to obtain the following second-order differential equation:This equation can be written in a more common form:α is called "attenuation", which is used to measure the attenuation rate of the transient response of this circuit when the external input is removed. ω0 is the angular resonance frequency. These two coefficients are given by:The damping coefficient ζ is another commonly used parameter, defined as the ratio of α to ω0:1.2 What is Transient Response of RLC Circuit?Figure2. Transient ResponseThe figure shows the underdamped and overdamped responses of the series RLC circuit. The critical damping is drawn with a thick red curve. These drawings are unified when L = 1, C = 1 and ω0=1. According to the value of different damping coefficient ζ, the solution of the differential equation has three different situations, namely: under-damping (ζ<1), over-damping (ζ>1), and critical damping (ζ=1).The characteristic equation of the differential equation is:The roots of this equation are:The general solution of this differential equation is the linear superposition of two exponential functions:The coefficients A1 and A2 are given by the boundary conditions of the specific problem.The following video introduces how to analyze RLC circuits by way of second order differential equations. Both parallel and series RLC configurations are discussed in it, looking primarily at Natural Response, but also touching on Step Response.RLC Circuit Response Explanation1.2.1 Over-damped responseThe over-damped response (ζ>1) is:Overdamping response is a transient current without oscillation attenuation.1.2.2 Underdamped responseThe underdamped response (ζ<1) is:Through the trigonometric identities, these two trigonometric functions can be expressed by a phased sine function:The underdamped response is an attenuated oscillation with a frequency of ωd. The rate of oscillation decay is α. The α in the index describes the envelope function of the oscillation. B1 and B2 (or B3 and phase difference φ in the second form) are arbitrary constants and are determined by boundary conditions. The frequency ωd is given by:This is the so-called damped resonance frequency or damped natural frequency. It is the frequency at which the circuit naturally vibrates when driven by no external source. The resonant frequency ω0 is the resonant frequency of the circuit when it is driven by an external source, and is often called the undamped resonant frequency in order to facilitate the distinction.1.2.3 Critical damping responseThe critical damping response (ζ=1) is:1.3 Laplacian DomainThe Laplace transform can be used to analyze the AC transient and steady-state behavior of the RLC series circuit. If the waveform generated by the above voltage source is V(s) after Laplace transform (where s is the complex frequency s=σ+iω), then Kirchhoff’s voltage law is applied in the Laplace domain:Among them, I(s) is the current after Laplace transform. Solve for I(s):After rearranging, the following formula can be obtained:1.3.1 Laplace admittanceSolve for Laplace admittance Y(s):The above formula can be simplified by using the parameters α and ωo defined in the above content, and we can get:1.3.2 Pole and zeroThe zero point of Y(s) is s such that Y(s)=0: s=0 and |s|⟶ ∞; the pole of Y(s) is s such that Y(s)⟶ ∞. Solve the quadratic equation. Get:The poles of Y(s) are the roots s1 and s2 of the characteristic equation of the differential equation mentioned above.1.3.3 Sine steady stateThe sine steady state can be represented by letting s=jω, where j is the imaginary unit. Substitute this into the amplitude of the above equation:The function of the current with ω as the variable isThere is a peak.In this special case, ω in this peak is equal to the undamped natural resonance frequency:1.4 RLC Series Resonance FormulaThe so-called series resonance formula refers to the study of the energy value of the voltage and current of the series circuit to reach the same phase, and the inductance of the inductance in the circuit and the capacitive reactance in the capacitor are equal in value. Therefore, in the study of the resistance characteristics of the circuit, In the case of a given terminal voltage, the maximum current is released, and the active power consumed will also be the maximum.Figure3. RLC series resonance formulaResonance definition: The energy of the L and C_ elements in the circuit are equal. When a reactance element in the circuit releases energy, the other reactance element must absorb the same energy, that is, energy pulsation occurs between the two reactance elements.  When series resonance occurs:Inductive reactance XL = capacitive reactance XCSource voltage U = resistance voltage URInductor voltage UL = Capacitor voltage UCInductor's reactive power QL = Capacitor's reactive power QCTotal circuit impedance Z=resistance value RApparent power S = resistance power PExplanation: When the circuit resonates, it must have two components: inductor L and capacitor C, and the frequency corresponding to resonance is called "resonant frequency" or resonant frequency, generally we use fr to indicate.1.5 Phasor Diagram of RLC Series Circuit(1) Phasor diagram of voltage and currentU&=U&R+U&L+U&CFigure4. Phasor diagram of voltage and currentFigure5. Phasor diagram of voltage and current(2) Voltage triangleThe relationship between the voltage triangle and the impedance triangle: divide the effective value of the voltage triangle by I to get the impedance triangle.Figure6. Voltage triangle● The relationship between the total voltage and the effective value of each part of the voltage:● The effective value relationship between total voltage and total current: U=I|Z|● The phase difference relationship between total voltage and total current:II RLC Parallel CircuitFigure7. RLC Parallel CircuitV-supply voltageI-circuit currentR-resistanceL-InductanceC-capacitanceThe characteristics of the RLC parallel circuit can be handled by the duality (electrical circuits) of the circuit. The RLC parallel circuit is treated as the dual impedance of the RLC series circuit, so it can be analyzed in a similar way to the RLC series circuit.The attenuation α of the RLC parallel circuit can be obtained by the following formula:If the factor of 1/2 is not considered, the damping coefficient of the RLC parallel circuit is exactly the reciprocal of the damping coefficient of the RLC series circuit.Frequency domainAdd the admittance of each element in parallel to obtain the admittance of this circuit:After capacitors, resistors, and inductors are connected in parallel, the impedance at the resonance frequency is the maximum, which is the opposite of the case where capacitors, resistors, and inductors are connected in series. The RLC parallel circuit is an antiresonator.In the figure below, it can be seen that if a constant voltage is used for driving, the frequency response of the current has a minimum value at the resonance frequency ω0=1/√LC. If it is driven by a constant current, the frequency response of the voltage has a maximum value at the resonance frequency, which is similar to the frequency response graph of the current in an RLC series circuit.Figure8. Sinusoidal steady state analysisNormalize with R = 1 ohm, C = 1 Farad, L = 1 Henry, and V = 1.0 VoltIII The Difference Between Series Resonant Circuit and Parallel Resonant CircuitIn an AC circuit containing resistance, inductance and capacitance, the voltage at both ends of the circuit and its current are generally out of phase. If the circuit parameters or the power supply frequency are adjusted to make the current and the power supply voltage in phase, the circuit is resistive, which is called resonance for the working state of the circuit at this time.Resonance is a specific phenomenon of sinusoidal AC circuits. It is widely used in electronics and communication engineering. However, in power systems, resonance may damage the normal operation of the system.Resonance is generally divided into series resonance and parallel resonance. As the name implies, series resonance is the resonance that occurs in a series circuit. Parallel resonance is the resonance that occurs in a parallel circuit.3.1 Series Resonance3.1.1 IntroductionIn a series circuit composed of resistance, inductance and capacitance, when the capacitive reactance XC and the inductive reactance XL are equal, that is, XC=XL, the voltage U and the current I in the circuit have the same phase, and the circuit presents pure resistivity. This phenomenon is called series resonance. When the circuit is in series resonance, the total impedance in the circuit is the smallest, and the current will reach the maximum. 3.1.2 Conditions for the occurrence of series resonanceIn order to resonate in a series circuit, certain conditions must be met.When UL=UC, that is, XL=XC,. Voltage and current are in phase, and series resonance occurs in the circuit. From ωL=1/ωC, ω0=1/√LC can be obtained, and the resonance frequency is f=f0=1/2π√LC. 3.1.3 Characteristics of series resonance circuit● Minimum total impedance● When the power supply voltage is constant, the current is the largest● The circuit is resistive, and the voltage on the capacitor or inductor may be higher than the power supply voltage 3.1.4 Energy changes in the circuit at resonanceThe circuit absorbs Q=0 from the power supply, and the circuit energy exchanges between the electric field and the magnetic field inside the circuit during resonance. The power supply only provides energy to R.High voltage may damage the device. Series resonance should be avoided in the power system. And series resonance is widely used in radio engineering.3.2 Parallel Resonance3.2.1 IntroductionIn a circuit where an inductance and a capacitor are connected in parallel, when the size of the capacitor just makes the voltage and current in the circuit have the same phase, that is, when the power supply is consumed by resistance and becomes a resistance circuit, it is called parallel resonance.Parallel resonance is a complete compensation. The power supply does not need to provide reactive power, only the active power required by the resistance. At resonance, the total current of the circuit is the smallest, and the current of the branch is often greater than the total current of the circuit. Therefore, parallel resonance is also called current resonance.When parallel resonance occurs, a large current flows in the inductance and capacitance components, which will cause the fuse of the circuit to blow or burn the electrical equipment; however, it is often used in radio engineering to select signals and eliminate interference. 3.2.2 Parallel resonance conditionsIn the following two types of circuitsFigure9. Two types of circuitsThe resonant frequency formula of (a) has been discussed above, and (b) is determined by,We can get.Under normal circumstances, the coil resistance R is much smaller than XL, therefore, ignoring R we can getthat is f=f0=1/2π√LC. 3.2.3 Features of parallel resonant circuit● When the voltage is constant, the current is the smallest at resonance● Maximum total impedance● The circuit is resistive, and the branch current may be greater than the total currentIV Application of RLC Circuit Resonance4.1 Application of Series Resonance CircuitThe use of series resonance to generate power frequency high voltage, which is used in high voltage technology to do withstand voltage test for power equipment such as transformers, can effectively find dangerous concentrated defects in the equipment, and is the most effective and direct way to test the insulation strength of electrical equipment Methods. Used in radio engineering, series resonance is often used to obtain a higher voltage.In the radio, the series resonance circuit is often used to select the radio signal. This process is called tuning. The following figure shows a typical circuit.Figure10. A typical circuit for tuningWhen the electric waves of various signals of different frequencies generate electric signals of different frequencies on the antenna, they are induced to the coil 2L through the coil 1L. If the oscillation circuit resonates to a certain signal frequency, the current of the signal in the loop is the largest, and a voltage CU higher than the signal voltage Q times is generated across the capacitor. For other signals of various frequencies, because no resonance occurs, the current in the loop is very small, which is suppressed by the circuit. Therefore, the capacitor C can be changed to change the resonant frequency of the loop to select the desired radio signal.4.2 Application of Parallel Resonance CircuitThe application of LC parallel resonant circuit in communication electronic circuit is determined by its characteristics. Specifically, it mainly includes three categories. One is working in resonance, as a frequency-selective network application. At this time, it appears as a large resistance and outputs a larger voltage under the excitation of current; the second is working in detuning The state, present as inductive or capacitive at this time, together with other inductances and capacitors in the circuit, satisfies the oscillation conditions of the three-point oscillation circuit to form a sine wave oscillator; the third is to work in a detuned state, that is, to work on the amplitude-frequency characteristic curve Or one side of the phase-frequency characteristic curve to realize amplitude-frequency conversion, frequency-amplitude conversion, frequency-phase conversion, and phase-frequency conversion to form an angle modulation and demodulation circuit. (1) LC parallel resonant circuit used as frequency selective matching networkFrequency selection is to select useful frequency components from the input signal and suppress useless frequency components or noise. In communication electronic circuits, the LC parallel resonant circuit is the most commonly used as a frequency selection network. It is widely used in high-frequency small-signal amplifiers, Class C high-frequency power amplifiers, mixers and other circuits. The common feature of these circuits is that the LC resonant circuit is not only a frequency-selective network. Through the connection of the transformer, it also plays the role of impedance transformation, reducing the impact of the amplifier tube or the load on the resonant circuit, and obtaining better selectivity. . (2) The LC parallel resonant circuit of the overtone crystal oscillator as a capacitorUnder the action of the applied alternating voltage, in the mechanical vibration generated by the quartz crystal, in addition to the fundamental frequency mechanical vibration, there are many odd frequency overtones. When a crystal oscillator with a very high operating frequency is required, overtone crystal oscillators are often used. The figure below shows the overtone crystal oscillator.Figure11. Circuit composition and reactance curve of L1C1 circuitIn the above figure, the quartz crystal and the CL branch are inductive. The quartz crystal, C2, and L1C1 loop together form a three-point oscillator. According to the composition principle of the three-point oscillator (shooting the same), the L1C1 resonant circuit should be capacitive. Assuming that the quartz crystal in the figure is working at the 5th overtone frequency, the nominal frequency is 5 MHz. In order to suppress the parasitic oscillation of the fundamental frequency and 3rd overtone, the L1C1 loop should be tuned between the 3rd and 5th overtone frequency, that is, 3~ Between 5 MHz.  From the reactance characteristic curve of the L1C1 resonant circuit shown in Figure (b), it can be seen that for the 5th overtone frequency of 5 MHz, the L1C1 circuit is capacitive, and the circuit meets the three-point oscillation condition and can oscillate. For the fundamental and third harmonics that are less than the resonance frequency of the L1C1 loop, the loop has an inductive characteristic, which does not conform to the principle of different components and cannot produce oscillation. For overtones of 7 times and above, although the L1C1 circuit is also capacitive, the equivalent capacitance at this time is too large, the amplitude starting conditions cannot be met, and the oscillation cannot be generated. (3) LC parallel resonant circuit that realizes the functions of amplitude-frequency conversion and frequency-phase conversionThe phase-frequency characteristic of the impedance of the LC parallel resonant circuit is a monotonous curve with a negative slope. The linear part of the curve can be used to perform a linear conversion between frequency and phase. This is mainly used in the phase frequency discrimination circuit; the same, the LC parallel resonant circuit The linear part of the impedance's amplitude-frequency characteristic curve can also perform the linear conversion between frequency and amplitude, so it has also been applied in the slope frequency discrimination circuit.V Frequently Asked Questions about RLC Circuit1. Is LCR and RLC circuit the same?Yes. An RLC circuit (also known as a resonant circuit, tuned circuit, or LCR circuit) is an electrical circuit consisting of a resistor (R), an inductor (L), and a capacitor (C), connected in series or in parallel. This configuration forms a harmonic oscillator. 2. What is the resonant frequency of the RLC circuit?What is Resonance in the RLC circuit? Resonance is the phenomenon in the electrical circuit, where the output of the circuit is maximum at one particular frequency. And that frequency is known as the resonant frequency. At the resonant frequency, The capacitive reactance and inductive reactance are equal. 3. Is the RLC circuit linear?In an RLC circuit, the most fundamental elements of a resistor, inductor and capacitor are connected across a voltage supply. All of these elements are linear and passive in nature. 4. What is the bandwidth of the RLC circuit?The bandwidth of any system is the range of frequencies for which the current or output voltage is equal to 70.7% of its value at the resonant frequency, and it is denoted by BW. 5. What is the second-order circuit?A second-order circuit is characterized by a second-order differential equation. It consists of resistors and the equivalent of two energy storage elements. 6. What is the first-order circuit?A first-order circuit can only contain one. energy storage element (a capacitor or an. inductor). The circuit will also contain. 7. What is the half-power frequency?The frequencies for which current in a series RLC (or a series tuned) circuit is equal to 1/√2 (i.e. 70.71%) of the maximum current (current at resonance)are known as Half Power Frequencies. 8. What is the natural response of the RC circuit?The natural response tells us what the circuit does as its internal stored energy (the initial voltage on the capacitor) is allowed to dissipate. It does this by ignoring the forcing input (the voltage step caused by the switch closing). The "destination" of the natural response is always zero voltage and zero current. 9. What is the difference between first-order and second-order filters?The main difference between a 1st and 2nd order low pass filter is that the stopband roll-off will be twice the 1st order filters at 40dB/decade (12dB/octave) as the operating frequency increases above the cut-off frequency ƒc, point as shown. 10. What is the use of a resonant circuit?One use for resonance is to establish a condition of stable frequency in circuits designed to produce AC signals. Usually, a parallel (tank) circuit is used for this purpose, with the capacitor and inductor directly connected together, exchanging energy between each other. 

CatalogⅠ What is Coolant Temperature SensorⅡ Function and Structure of Coolant Temperature SensorⅢ The Working Principle of Coolant Temperature SensorⅣ Application of Coolant Temperature Sensor in Vehicles  4.1 Location on Automobiles  4.2 Ways of Testing Coolant Temperature SensorⅤ How to Replace the Faulty Coolant Temperature  SensorⅥ Frequently Asked Questions about Coolant Temperature Sensor Analysis Ⅰ What is Coolant Temperature SensorEvery driver is aware that coolant/antifreeze is applied to keep an engine operating at peak efficiency. However, how do cooling systems recognize when the engine is at the proper operating temperature? We take a closer inspection at coolant temperature sensors in this guide, providing information on what they do and how they work, as well as step-by-step instructions for diagnosing and replacing a faulty sensor. A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor)) measures the temperature of the coolant/antifreeze mix in the cooling system, indicating how much heat the engine is producing. The sensor communicates with the vehicle's ECU and continuously monitors coolant temperature to ensure that the engine is operating at the proper temperature. Ⅱ Function and Structure of Coolant Temperature Sensor The coolant temperature sensor is installed on the water jacket of the engine block or cylinder head, contracting with the coolant directly. The CTS is applied to detect the temperature of the engine coolant. The internal part is equipped with a negative thermistor with negative temperature characteristics. The feature of a negative thermistor is that the higher the temperature, the smaller the resistance, the lower the temperature, the greater the resistance.Figure1: the circuit image of coolant temperature sensor The signal of the coolant temperature sensor is a correction signal, and its function is to inspect the temperature of the engine coolant. The temperature of the engine coolant transmit the signal to the ECU, and the ECU  measured temperature and correct the fuel injection volume according to the signal indication. When the cold car starts or the engine warms up, the ECU will correct the fuel injection.When the car is hot, the ECU will correct to inject the leaner mixture; the same way, when the engine coolant temperature signal is detected, the ECU controls the cooling and the fan is turned on and off. Ⅲ The Working Principle of Coolant Temperature Sensor Generally, the structure of the coolant temperature sensor seems to be a negative thermistor. Therefore, its temperature is inversely proportional to resistance, and its voltage is also inversely proportional to resistance. The range of temperature changes: -40 to 195°C. When the engine cools down from the start of the cold car to the hot car, the parameters of the fluid temperature sensor gradually increase, and the vehicle is idling when the engine is completely warmed up. The coolant temperature should be 85～105℃ when operating, if the parameter of CTS is  -40℃, it indicates that there is a short-circuit in CTS. If the parameter is higher than 185℃, it means that there was the same failure as-40℃. The voltage change range is 0 ~ 5V. When the temperature parameter is -40℃, the corresponding voltage is 4.98V，while the temperature parameter is 185℃, the corresponding voltage is 0.02V. The cooling system in a car with an internal combustion engine keeps the engine at the proper temperature and prevents it from overheating.  The temperature of the liquid coolant is measured by an engine coolant temperature sensor or ECT. A Negative Temperature Coefficient (NTC) thermistor is a type of engine cooling temperature sensor in which the electrical resistance decreases as the temperature rises. The ECT sensor's tip protrudes into a cooling system passage and is submerged in coolant.This vedio show that how coolant temperature sensor works Ⅳ Application of Coolant Temperature Sensor in Vehicles4.1 Location on Automobiles Many automobiles have multiple coolant temperature sensors. The primary ECT sensor (ECT sensor 1) is usually located near the thermostat in the cylinder head or block, or on the thermostat housing. Sensor for electrocardiography (ECT) the engine computer, or PCM, is connected to the ECT sensor. A second coolant temperature sensor could be installed in the radiator or in another part of the engine. Instead of or in addition to the ECT sensor, some cars use a cylinder head temperature or CHT sensor. The CHT sensor (shown in the photo) works in the same way, but it measures the temperature of the cylinder head metal rather than the coolant temperature. This enables the CHT sensor to accurately measure the temperature of the engine even when coolant is lost. This may help prevent overheating in some cases. The main computer is connected to an ECT sensor (powertrain control module or PCM). The PCM provides a constant reference voltage (typically 5 volts) and monitors the ECT sensor signal. When the temperature reaches a pre-determined level, the PCM adjusts the engine performance and operates the electric radiator fans based on this signal. If the sensor signal is missing or outside of the expected range, the PCM illuminates the Check Engine light and records the associated trouble code. 4.2 Ways of Testing Coolant Temperature SensorTesting the ECT/CHT Sensor Resistance: One method is to measure the sensor's resistance at various engine temperatures and compare the results to the service manual's specifications.We tested the resistance of the ECT sensor in this car, for example. Only when the sensor is disconnected from the circuit can the resistance be measured. The reason for this is that measuring the resistance of any electrical component that is still connected to the circuit will result in inaccurate results. When the engine was cold, the resistance was 2,953 Ohm. After the engine was fully warmed up, it dropped to 248.5 Ohm; see photo. This sensor complies with the manufacturer's specifications. Of course, the resistance specifications differ from car to car. Figure2:one way to test the resistance of senser  Checking the ECT/CHT Sensor Voltage:With the ignition on, another way to test the sensor is to measure the voltage across the sensor terminals. The voltage of the engine coolant temperature (ECT) sensor is measured. The voltage of the ECT sensor is being checked. The engine computer is linked to the sensor (PCM). The reference voltage (typically 5 volts) is supplied by the PCM, and the sensor ground is provided by another wire. The ground as well as the reference voltage must be checked first. The voltage drops as the sensor's resistance decreases as the engine warms up. We probed the ECT sensor inversely in this photo to keep it connected to the circuit. We measured 3.96 Volt when the car was cold. The voltage dropped to 0.988 Volt on a fully warmed-up engine. The multimeter will read 5 volts when the sensor is disconnected. If you don't see any voltage, the circuit is either open or shorted to the ground. One of the wires in the sensor harness, for example, could break or rub against a metal part, causing a short. Figure3: another way to test sensor Voltage  4.3  Symptoms of a bad or failing coolant temperature Poor fuel economy Poor fuel economy is one of the first signs of failure with the coolant temperature sensor. If the coolant temperature sensor fails, it can send a false signal to the computer, causing fuel and timing calculations to be thrown off. It's not uncommon for the coolant temperature sensor to fail and send a signal to the computer that's always cold. This will trick the computer into thinking the engine is cold when it isn't, causing it to consume more fuel than is necessary. The poor fuel economy will suffer as a result, and engine performance may suffer as a result. Black smoke from engine Black smoke from the vehicle's exhaust is another sign of a possible problem with the coolant temperature sensor. If the coolant temperature sensor fails and sends a cold signal to the computer, the computer may become confused and enrich the fuel mixture unnecessarily. If the fuel mixture becomes too rich, it will burn up in the exhaust pipes, resulting in black smoke. In severe cases, the black smoke may be so awful that the vehicle can not be started. Overheating engine An overheating engine is another sign of a problem with the coolant temperature sensor. The coolant temperature sensor can also fail in such a way that it sends an always-hot signal. This can cause the computer to compensate for a lean signal incorrectly, resulting in overheating, misfires, and even engine ping. Check Engine Light comes on Another sign of a problem with the coolant temperature sensor is an illuminated Check Engine Light. If the computer detects a problem with the sensor's signal or circuit in some vehicles, the Check Engine Light will illuminate. The Check Engine Light will stay illuminated until the trouble is resolved. Ⅴ How to Replace the Faulty Coolant Temperature SensorBegin with a cold engine. Drain the cooling system by jacking the car up and using jack stands. Wear safety glasses and glovesMterials:1. coolant collection pan2. flat head screwdriver3. new coolantTools:1. eyewear and golves 2. pliers3. funmel4. jack standsTip: Only do this job when the engine is completely cold and hasn't been running for at least an hour. Because you'll be underneath the car and the risk of coolant splashing in your face is high, it's a good idea to protect your face with a safety shield. If the engine is not cold, wear safety glasses and gloves to protect your hands from the hot coolant.  Step1: Locate the SensorThe CTS is usually found near the radiator or thermostat housing in the front of the engine. You may need to use a light or torch to locate it because it's a small component that's often found lower down inside the engine bay. If it's near the thermostat housing, removing the engine cover can also help you find it.Figure4: firstly, locate the coolant sensor   Step2: Remove the Connector Cable from the Terminal A connector connects the CTS to the ECU, which you must unfasten and remove. Do this with caution, as the plastic connector and wiring can be brittle and require replacement if they break. Remove the connector and place the cable somewhere out of the way.Figure5: release the connector   Step3: Loosen and Remove the Old Sensor Coolant sensors are installed similarly to spark plugs, so they must be unscrewed to be removed. Carefully loosen the sensor in an anticlockwise direction with a deep socket and ratchet, without applying too much pressure. A squirt of release spray can aid in the unsticking of stuck sensors. Remove the sensor from the socket by unscrewing it by hand once it is loose. Because coolant is likely to leak at this point, have a new one on hand or consider draining the coolant if necessary.Figure6: Remove the clip and old sensor   Step4: Install the New Sensor Clean the area with a rag or cloth to remove any dust or debris that could influence the new CTS' performance. Set the new sensor in the threads and hand-twist clockwise to ensure it is securely seated in the socket. Tighten the sensor with a torque wrench to the amount specified in the manufacturer's instructions.Figure6: install the new coolant sensor  Step5 : Reinstate the Connector Cable The only thing left to do now is reconnect the cable after the new sensor has been installed. Make sure the connector is clean and free of debris before carefully plugging it into the new sensor and tightening any clips to ensure a good connection. Start the engine to ensure the new sensor is working, and as it warms up, keep an eye on the temperature gauge on the dash to ensure the correct temperature is maintained.Figure7: reconnect the cableⅥ Frequently Asked Questions about Coolant Temperature Sensor Analysis1. Can you drive with a bad coolant sensor?It is possible to drive a vehicle with a faulty coolant temperature sensor as the management system defaults to a static reading. A vehicles coolant sensor is a critical component used by the engine management system. It directly effects, cooling and fueling of the engine and therefore effects how the engine performs. 2. What does the coolant temperature sensor do?A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor) is used to measure the temperature of the coolant/antifreeze mix in the cooling system, giving an indication of how much heat the engine is giving off. 3. What causes a coolant temperature sensor to fail?The engine may run in fail-safe mode:Many Check Engine light codes related to the (ECT) sensor; could also be caused by other reasons. Such as a bad thermostat or issues with the cooling system; including even a leaking head gasket. Therefore, The problem must be properly diagnosed. 4. How long do coolant temp sensors last?About 100,000 miles. Often, the engine coolant temperature sensor must be replaced at about 100,000 miles. If you don't properly maintain the engine cooling system, the sensor could fail much earlier. 5. Do you need to drain coolant to change coolant temperature sensor?Open the radiator valve and drain about two to three quarts of coolant. You only need to remove enough to drop the level below the sensor. Then close the drain valve. This will minimize coolant waste when you remove the sensor. 6. Can you run a car without a temperature sensor?Generally it should be ok to drive without the thermostat fitted, as it will only cause the engine to take longer to reach operating temperature. The thermostat is designed to allow the engine to reach ideal operating temperature as quickly as possible, so it would not be recommended to drive without it. 7. Can a bad coolant temp sensor cause rough idle?A faulty coolant sensor that always reads cold may cause the fuel control system to run rich, pollute and waste fuel. A coolant sensor that always reads hot may cause cold drive ability problems such as stalling, hesitation and rough idle. ... This also affects engine performance and fuel economy. 8. Does coolant temp sensor affect AC?In a properly operation system the engine coolant temperature should not affect the cooling of the air conditioner. The A/C condenser is located in front of the radiator and is first to receive the incoming airflow.    

IntroductionⅠ AG13 Battery Basics    1.1 What is a AG13 Battery?    1.2 AG13 Battery Specifications and UsageⅡ AG13 Battery ReplacementⅢ AG13 Battery vs AG10 BatteryⅣ AG13 vs.LR44 vs. A76    4.1 The Similarities: Between LR44, AG13 and A76    4.2 The Differences: Between LR44, AG13 and A76Ⅴ Popular Manufacturers and Their FeaturesⅥ Important Considerations while PurchasingⅦ FAQ    1. Which is Better Alkaline or Silver Oxide?    2. What is the Replacement for an AG13 Battery?    3. What Duracell Battery Replaces LR44?    4. What are the Long-term Effects of Swallowing Button Batteries?    5. What will Happen if you Mixed up Batteries?    6. What Batteries are Compatible with LR44?    7. Can I Charge the AG13 Battery？     8. Can you Replace an AG13 Battery with an LR6 Battery?    9. What Battery is Equivalent to AG13?   10. What is a LR44 Battery Used for? IntroductionIf you want to learn more about the AG13 battery series or if you already know about them and want to buy some, you've come to the correct place.Ⅰ AG13 Battery Basics1.1 What is a AG13 Battery?The AG13 battery is intended for devices that require a steady low power supply. They are most commonly utilized in hearing aids and electronic wristwatches. Because the power source resembles a tablet, the AG13 battery is sometimes known as a tablet.AG13 batteries, also known as Alkaline Zinc Manganese button batteries, are mostly used in timepieces. They are equivalent in size and voltage to the SR44 batteries, commonly known as 357. They are also known as LR44, 157, A74, or LR 1154. The latter, on the other hand, are Silver Oxide batteries, which have a capacity of around three times as long a charge but a price that is three times as costly.The standard voltage of an AG13 or LR44 battery is 1.5 volts, and the termination voltage is 0.9 volts. They have a capacity of 130mAh. The cell measures 11.6 x 5.4mm.Alkaline Zinc Manganese has the chemical formula (-) / MnO2 (C) (+) Zn MnO2. Other industrial names for AG13 batteries include LR44, 157, A76, and LR1154.1.2 AG13 Battery Specifications and UsageThe manganese-zinc battery AG13 is a type of manganese-zinc battery. Manganese-zinc is a well-known chemical element that functions as an energy generator. This kind has a low nominal capacity but can work for several years due to its low coefficient of self-discharge.The following are the primary technological aspects of the tiny battery:11.6 mm in diameter5.4 mm in height;2-gram weight (can vary by several tenths of a gram from different manufacturers).The battery has a nominal capacity of 110 mAh. However, some manufacturers provide products with capacities of up to 190 mAh. 1.55 volts is the rated voltage.This battery is unique in that it can work in a wide temperature range. They work at temperatures ranging from -2 to +70 degrees.Because they are installed in a variety of equipment, this is a useful quality. Temperamental readings can be high as a result of overheating inside the gadget, however, the AG13 battery is unaffected.(表格)Parameter     ValueBasic designation  AG13The form      Tablet (coin)View    Manganese-alkalineCapacity      110-190 mA / h Voltage 1.55 VDiameter       11.6 mm Height 5,4 mmWeight  ~ 2 grⅡ AG13 Battery ReplacementThe AG13 battery is a non-rechargeable main cell battery. The AG13 battery has a nominal voltage of 1.5V and is a small and inexpensive Alkaline battery. This alkaline button cell battery gives your gadget a long battery life and good continuous power sources. It works well in both cold and hot temperatures. An alkaline battery is a type of battery that combines manganese dioxide and zinc to initiate a reaction. It is a less expensive alternative to silver oxide batteries, but it still has a high capacity and a long lifespan.Specifications of the battery: Model #: AG13 Battery1.5 volts nominal voltageAlkaline chemistry180 mAh capacity5.4mm in height11.6mm in diameter039800049223 UPCThis alkaline button cell battery is used in:WatchesClocksCalculatorsCamerasRemote ControlsCamcordersElectronic GamesDigital CamerasPDAsChildren ToysDigital Voice RecordersElectronic InstrumentsMP3 PlayersBlood Glucose, Cholesterol Testing MetersMany other electronic productsCross Reference to the following battery:Energizer A76Vinnic L1154MaxellLR44/AG13Panasonic LR44GP LR44Phillips A76EXELL A76Tenergy AG13IEC: LR44Varta V13GARayovac A76-1Duracell PX76A/76ARenata LR44Sony A76/LR44Kodak KA76Ultralast UL76AUCAR A76Mallory LR44Berec BLR44Chateau AG13CNB G13AEveready A76NEDA 1166AThe AG13 battery is designed for the following models:The AG13 is also compatible with the following battery models.AG13, LR44 Watch, LR44 1.5V, GPA76 Alkaline, L1154, L1154H, AG13 Button Cell, GPA76 Button, BLR44, 1154, GPA76, LR44 Soda Button Cell, AG13 Button, 357A Button Cell, GPA76 Alkaline Cell, L1154F Energy, CX44, LR44 Alkaline, L1154F Energy, CXAWI S05 / S15Gold Peak GP57 / / GPA76Panasonic SP76 / SR44Beric BLR44JIS G13F / G13R / GS13Pentax ME Super / LR44/ SR44Bright Star S15Kodak KS76Renata 228 / R357Bulova 228Lumiscope 2018RadioShack 357 / 23-009CNB G13-AMallory LR44Rayovac RS76 / RS76-2 / RW22 / RW82/ RW42Chateau AG13MGA MGA-2200Sony 76-SCitizen 280-08 / 280-904Maxell 313 / LR44 / SR44P / SR07 / SR44SWSeiko SB-F9Duracell 10L14 / D357 / D76/ 10SL17 / MS76 / 303-357 / SR44 / MS76H / 76ANexxtech 357ATimex KA / T535BEnergizer 357 / 303/ A76/ BS07 / BSR44H / EPX76Phillips A76Toshiba SR44W / SR44SWGP76 Hyundai AG13Pentax LX S-76Varta V13GA/ V76PX / V76HSⅢ AG13 Battery vs AG10 BatteryIs an AG10 button battery the same as an AG13 button battery? No, their diameters are the same, but AG10 is thinner (about 3.1 mm vs. about 5.4 mm for the AG13). As a result, the AG13 has somewhat more than double the capacity of the AG10.If you're wondering which one you have, and AG10 is roughly the thickness of two US/Canadian pennies or Euro cents; an AG13 is roughly the thickness of three US quarters or Canadian toonies, slightly thicker than three Euro cents, or little less than the diameter of a pencil.An AG10 battery may fit in a device meant for an AG13, but it will most likely not establish good contact. If it fits, it will work, but only for a short while. An AG13 will very certainly not fit in a device built for an AG10.The IEC designation for the AG10 is SR1131 and for the AG13 is SR1154; the first two digits are the diameter in millimeters and the second two digits are the height in tenths of millimeters. Confusion ensues when the AG10/SR1131 is referred to as SR54 and the AG13/SR1154 is referred to as SR44. This could be the reason for your confusion: SR54 is not the same as SR1154.These are silver oxide batteries (thus the "AG" suffix); alkaline batteries are also available. The alkaline equivalent of the AG10 is LR54 or LR1131; for the AG13, it is LR44 or LR1154. The "L" models are less expensive, but they don't last as long—you probably won't notice the difference.If you live in the United States, you can usually get Duracell and Energizer versions of these batteries at your local drugstore. The Duracell 389/390 is the Duracell counterpart of the AG10 battery, and the Energizer equivalent is likewise 389; both are silver oxide batteries. Duracell's counterpart is 303/357 or 303/357/76 (silver oxide), while Energizer's equivalent is A76 (alkaline).Ⅳ AG13 vs.LR44 vs. A76As previously stated, mercury-oxide batteries are no longer commercially available or have been phased out due to their dangerous mercury content.When compared to alkaline batteries, zinc-air batteries have a lower voltage output (1.4 V vs. 1.5V). However, some battery types may store 600 or 700 mAh, making them excellent for devices with high power consumption, such as digital cameras and MP3 players.Silver-oxide batteries are like a superior form of alkaline batteries because they have 1.55 volts instead of the standard 1.5, and their voltage remains consistent at roughly 12 when in operation. Smaller gadgets should be powered by silver-oxide batteries. Alkaline batteries are less expensive and more adaptable, but they lack the voltage required to power such gadgets. You're aware that silver-oxide batteries are more expensive than alkaline batteries, but the price difference is justified when you consider their features and performance. The cost difference between them is negligible in larger shipments.Alkaline batteries are a great choice for everyday use and small electronic gadgets. They're inexpensive, dependable, and offer a reasonable capacity of 110-130 mAh, depending on your device's cut-off voltage.AG13 (Eurobatt): Alkaline battery with 1.5V, 0.9V nominal, and cut-off voltages, with a capacity of 130 mAh.LR44 (Murata): Alkaline battery having 1.5V, 0.9/1.2V nominal, and cut-off voltages, with a capacity of 130 mAh.SR44 (Murata): Silver oxide battery with 1.55V nominal, 1.2V nominal, and cut-off voltages, with a capacity of 155 mAh.357 (Energizer): Silver oxide battery having 1.55V, 1.2V nominal and cut-off voltages, and a capacity of 150 mAh.4.1 The Similarities: Between LR44, AG13 and A76The LR44, AG13, and A76 have significant similarities that allow them to be used interchangeably.Battery size, chemistry, and voltage are all shared by the LR44, AG13, and A76 battery. Furthermore, none of these batteries is rechargeable.Size: 11.6mm x 5.4mm (Diameter x Height)The physical size is the most evident comparison. Any battery meant to be used in place of an LR44 should have a diameter of 11.6mm and a thickness of 5.4mm to meet international standards. The size is crucial, as even a minor difference means that the battery will not fit in many of the compact devices for which it is designed.Chemistry: AlkalineAlkaline is the most common chemistry for these three battery categories. The AG13 battery and A76 battery designations, on the other hand, can deviate from the standard because they are manufacturer's component numbers.Energizer's AG13 type battery, for example, employs silver oxide chemistry. A silver oxide battery can live up to three times longer than an alkaline cell.The disadvantage of silver oxide batteries is their high cost. They are more expensive than alkaline equivalents, however, depending on how the batteries are utilized, a balance can be reached.Voltage: 1.5 – 1.55 VoltsWhen new, all kinds of this battery produce 1.5 or 1.55 volts. The important element here is how the voltage will decline when in use. Throughout its useful life, the voltage of a common alkaline battery will drop to roughly 1 volt. Silver oxide variants are more expensive and have more stable voltages over time, often maintaining at least 1.2 volts.Non-RechargeableNone of these batteries is rechargeable, and attempting to recharge them is risky.4.2 The Differences: Between LR44, AG13 and A76As previously demonstrated, the three battery types, LR44, AG13, and A76, are interchangeable. But are there any distinctions that might lead you to prefer one over the other?LR44 vs. AG13 vs. A76: Similarities & DifferenceBattery CapacityThe voltage will always be 1.55 volts, however, the capacity of the battery can fluctuate. The usual capacity of an LR44 battery is between 110 and 130 mAh.This is determined by the chemistry employed and the quality of the components. Silver oxide batteries can yield between 150 and 200 mAh, allowing them to last longer. Purchasing a branded product over a generic item will usually result in a more powerful battery, but it will be more expensive.Ⅴ Popular Manufacturers and Their Features You may have a preferred brand. Perhaps you've tried every brand and discovered one that lasts longer or performs better. Part numbers are assigned to objects by different manufacturers.There are numerous AG13 battery producers in both Russia and abroad. Replace with an analog battery from any firm that has the same size and weight as the original but is made by a different manufacturer.Duracell, Camelion, and Varta batteries are very efficient in terms of performance and durability. They can now be purchased in product marketplaces for 10 rubles.According to customer reports, they last around 20% longer than others, or roughly four years. Miniature power supplies and additional companies should be considered:EnergizerRenataMinamotoRobitonHearing Aid Battery 675 Batteries are installed in small items, and it is sometimes inconvenient to do so on their own, or power supplies are inadequately adjusted after installation. Special holders aid in the resolution of this issue. They can be added, although this raises the price slightlyⅥ Important Considerations while PurchasingThe AG13 battery must be of the appropriate size. Even a one-millimeter oscillation will not allow it to be repaired. Size information can be discovered in the device's instruction manual or on an old battery.In addition, consideration should be given to:power and voltage;voltage and capacitancethe holder's existence in the kit;a set of temperature settings for operationImportant! The concern of employing small food sources is that they can be swallowed by children. The materials induce toxicity if they enter the esophagus. Children should not be given devices containing such batteries.Ⅶ FAQ1. Which is Better Alkaline or Silver Oxide?The CR2 battery, which is used in cameras, weapon-mounted lights, golf rangefinders, EDC flashlights, and security gadgets, is highly regarded worldwide. A CR2 battery is a typical cylindrical lithium battery. This is the sort of battery that is found in cameras (such as the CR2).2. What is the Replacement for an AG13 Battery?Medic Batteries stocks high-quality lithium and silver oxide button cell batteries from Energizer. The Energizer 357 AG13 battery is a substitute for the LR44 and AG13 button cell batteries. The Energizer watch battery 377/376 replaces the SR626SW watch battery.3. Are AG13 and A76 Batteries the Same?The Energizer A76 battery replaces the LR44, AG13, and SR44 batteries. How to avoid issues with batteries in electronic devices. The Zero Mercury Energizer A76 is a 1.5 Volt alkaline button cell battery with several drains.4. What are the Long-term Effects of Swallowing Button Batteries?If a person swallows button batteries, they will feel a burning feeling in their throat and neck. If this occurs, get medical attention immediately because swallowing these types of cells can be dangerous.5. What will Happen if you Mix up Batteries?When two different battery types are used together, the one with the lower voltage will deplete faster than it would ordinarily. When charged and discharged at the same rate, the mixed cells are expected to have a similar life span.6. What Batteries are Compatible with LR44?The LR44 battery is a 1.5 V alkaline battery. AG13.L1154 is the most common comparable battery.7. Can I Charge the AG13 Battery？ Because of the design features and chemical ingredients utilized in the composition, the AG13 battery does not charge. This, however, is not a necessary quality. The power source has a low cost and can be used for several years without losing functionality. As a result, the question of whether AG13 can be ignited is not particularly important. It is only possible to charge batteries.8. Can you Replace an AG13 Battery with an LR6 Battery?LR6 is an Alkaline call in the AA size.AG13 Button Batteries are also known as 303, 357, LR44, L1154, A76...An LR6 would have the necessary voltage and current capacity. and are far more durable.However, because of significant physical size and shape variations, it would be difficult to engage the LR6 with contacts in a device using the button cell.If you connect it successfully, it will work for a much longer period of time. The majority of items that use an AG13 size button cell do so to attain a modest size and profile. That, too, will be defeated.9. What Battery is Equivalent to AG13?AG13Button Energizer 357 - AG13 Equivalent Cell BatteriesMedic Batteries carries the Energizer 357/303 battery, which is an AG13 equivalent. The Energizer357/303 replaces all AG13 button cell batteries, which are found in watches, medical equipment, laser pointers, and other electronic devices.10. What is an LR44 Battery Used for? The LR44 1.5V Battery is a 1.5-volt alkaline button cell battery that is intended for general use. The LR44 1.5V Battery is commonly found in watches, calculators, and medical devices. A button cell battery is a tiny, round battery with a diameter of 11.6mm (0.457 inches) and a thickness of 5.4mm (0.211 inches).           

IntroductionLED lights cannot directly use the conventional mains grid voltage, because of the characteristics of LED lighting. In order to meet the special voltage and current requirements of LEDs, a specially designed voltage conversion device must be used to make LEDs work normally. This device is an LED driver. LED drivers are usually switching mode devices that convert the input voltage (Typically 120-220 VAC or 12 VDC) into a voltage at which the current drawn by the LED's is equal to its drive current. The drive current is regulated for optimum brightness, led service life, and battery life. A drive current lower than the maximum drive current of an LED can greatly prolong service life. As a key part of LED lighting, the quality of LED drivers directly affects the performance of LED lighting.Choose the Correct LED Drivers For LED LightsNo matter how good the quality of the LED driver is, failure and maintenance are inevitable. This article will analyze the 10 failures in LED lighting design and its application based on the relevant technology and practical experience of the LED driver.CatalogIntroductionⅠ LED Driver Failure Analysis1.1 Forward Voltage Drop (Vf) Range1.2 Power Margin and Derating Requirements1.3 LED Working Characteristics1.4 Test Session1.5 Different Load with Different Test Results1.6 LED Driver Circuit Problem1.7 Wrong Phase Wring1.8 Grid Fluctuation1.9 Frequent Line Trips1.10 Drive CoolingⅡ LED Driver Maintenance2.1 Multimeter to Detect LED Driver2.2 Identify LED Power SupplyⅢ LED Driver Circuit Modulation3.1 Pulse Width Modulation (PWM)3.2 Pulse Frequency Modulation (PFM)3.3 Sliding-Mode ModulationⅣ One Question Related to LED DriverⅠ LED Driver Failure AnalysisThe LED driver is measuring current passing through LEDs using sense resistor and then increase or decrease the voltage to maintain constant current continuously. LEDs are kind of diode so they need DC voltage to operate so most of the LED drivers are boost and can vary output supply in wide range (example, 16V to 38V). They also have dimming control by PWM signal from microcontroller OR by having a manual potentiometer to change sense resistor. According to them, LED driver failures are complex, but we can follow the steps below to analyse.1.1 Forward Voltage Drop (Vf) RangeLED lamp load end is generally composed of a number of LEDs connected in series, and its working voltage Vo=Vf×Ns, where Ns represents the number of LEDs. And the Vf of an LED varies with temperature. Generally, at a constant current, Vf becomes lower at high temperatures and becomes higher at low temperatures. The LED lamp load working voltage is VoL at high temperature, and VoH represents a value at low temperature. When selecting an LED driver, consider that the driver output voltage range is greater than VoL～VoH.If the maximum output voltage of the LED driver is lower than VoH, the maximum power of the lamp may not reach the actual power required at low temperature. If the minimum voltage of the selected LED driver is higher than VoL, the output of the driver may exceed the working range at high temperature. And LED driver will work unstable, making the lights flicker.Considering the overall cost and lamp efficiency, don’t blindly pursue the ultra-wide output voltage range of the LED driver. Because the driver voltage is only in a certain range, its efficiency is the highest. When the range is exceeded, the efficiency and power factor (PF) will deteriorate. In addition, if the design of the driver output voltage range is too wide, high costs and unoptimized efficiency will be made. 1.2 Power Margin and Derating RequirementsIn general, the nominal power of the LED driver refers to the data measured under the rated environment and rated voltage. Taking into account different applications, most LED driver suppliers will provide power derating curves in their product specifications (common load vs. ambient temperature derating curves and load vs. input voltage derating curves).As shown in Figure 1, the red curve represents the power derating curve when the input is 120Vac, and its load varies with the ambient temperature. When the ambient temperature is lower than 50℃, the LED driver is allowed to be 100% full load. When the ambient temperature is as high as 70℃, the LED driver can only be derated to 60% of the load. When the ambient temperature changes between 50℃~70℃, the driver load varies with the temperature linearly.Figure 1. Power Derating Curve (Load vs Ambient Temperature)The blue curve represents the power derating curve when the input is 230Vac or 277Vac, and its load varies with the ambient temperature. The principle is similar to the above mentioning.As shown in Figure 2, the blue curve represents the derating curve of the LED driver when the ambient temperature is 55°C, its output power varies with the input voltage. When the input voltage is 140Vac, the load of the driver is allowed to be 100%, and the input voltage will be adjusted downward. If the output power remains the same, the input current will rise, resulting in input terminal loss and lower efficiency. When the device temperature rises, exceeding the rated temperature, which may cause the device to fail.Figure 2. Power Derating Curve (Load vs Input Voltage)Therefore, when the input voltage is less than 140Vac, the output load of the LED driver is required to linearly decrease as the input voltage decreases. According to the above derating curve and corresponding requirements, when choosing a LED driver, actual applying needs are important, as well as the derating margin. 1.3 LED Working CharacteristicsWhen the required input power is a fixed value, such as a fixed error of 5%, the output current can only be adjusted to the specified power for each lamp. Due to different working ambient temperature and different lighting time, the power of each lamp will vary greatly.Although there are considerations for marketing and business factors. However, the volt-ampere characteristic of the LED lamp determines that the LED driver is a constant current source, and its output voltage varies with the series voltage Vo of the LED load. When the efficiency of the driver is basically unchanged, its input power changes with Vo. And meanwhile, the overall efficiency of the LED driver will increase after thermal equilibrium. Under the same output power, the input power will decrease compared to the boot time.Therefore, when formulating requirements, LED driver users should first understand the operating characteristics of LEDs. Avoid suggesting indicators that do not meet the principles of operating characteristics, and indicators that far exceed actual requirements, resulting in excess quality and cost waste. 1.4 Test SessionSample test problems, for example, multi-brand LED driver samples all failed during the test. The reason is that a self-dual voltage regulator is used to directly power the LED driver for testing. After power on, the voltage regulator is gradually adjusted from 0Vac to the rated operating voltage of the LED driver. This kind of test operation can easily make the LED driver start and work with the load when the input voltage is very small, but this situation will cause the input current to be far greater than the rated value. And the internal input terminal related components, such as fuses, rectifier bridges, thermistors, etc. will fail due to excessive current or overheating, damaging the LED driver.The correct test method is to adjust the voltage regulator to the rated operating voltage range of the LED driver, and then connect the driver to power-on test. Of course, technically improving the design can also avoid the failure caused by this kind of test misoperation. That is, a starting voltage limit circuit and an input undervoltage protection circuit are set at the input of the driver. When the input does not reach the start-up voltage set by the driver, the driver does not work. When the input voltage drops to the input undervoltage protection point, the driver enters the protection state. Although the driver has a self-protection function and will not fail, you must carefully understand whether the purchased LED driver product has this protection before testing (considering the actual application environment of the LED driver, most LED drivers currently do not have this set). 1.5 Different Load with Different Test ResultsOn the one hand, when the LED driver is tested with LED lights, the result is normal; on the other hand, when driver tested with an electronic load, the result may be abnormal. Usually this phenomenon has the following reasons:1) The output instantaneous voltage or power of the driver exceeds the working range of the electronic load instrument. (Especially in CV mode, the maximum test power should not exceed 70% of the maximum power of the load. Otherwise, the load may instantaneously have overpower protection when loading, causing the driver to fail to work.)2) The characteristics of the electronic load instrument used are not suitable for measuring constant-current device. And the load voltage gear jumping, result in the drive to fail to work.3) Because there is a large capacitor inside the input of the electronic load meter. The test is equivalent to connecting a large capacitor in parallel with the driver output, which may cause the driver's current sampling work to be unstable. As we all known, the LED driver is designed to meet the working characteristics of LED lamps. The most practical test method is to use the LED lamp as a load, and connects an ammeter and a voltmeter in series to test. 1.6 LED Driver Circuit ProblemThe following conditions often cause damage to the LED driver:Connect AC to the DC output terminal of the driver, causing the driver to fail.Connect AC to the DC/DC output or input of the driver, causing the driver to fail.Connect the output terminal of the constant current to the dimming light, causing the driver to fail.Connect the phase wire to the ground wire causing the driver has no output and the housing is charged. 1.7 Wrong Phase WringTake an international example: the rated working voltage between each phase line and the neutral line is 220V, and the voltage between the phase line and the phase line is 380V. If the driver is connected to two phase wires, after power on, the LED driver input voltage exceeds the rated range, which cause the product to fail.As shown in Figure 3, V1 represents the first phase voltage, V2 represents the second phase voltage, and R1 and R2 respectively represent the drivers normally installed on the line. When the neutral line (N) on the circuit is disconnected, the drivers R1 and R2 on the two branches are connected to the 380V voltage after being connected in series. Because of the difference in input internal resistance, when one of the drivers is charged to start, the internal resistance becomes smaller. Most of the voltage may be applied to another driver, causing the overvoltage damage. Therefore, it is recommended that switches or short-circuiters on the same distribution branch should be disconnected together, not just cut off the neutral line. What’s more, do not put the power distribution fuse on the neutral line to avoid bad effect of the neutral line on the circuit.Figure 3. Neutral Line Open Circuit Diagram 1.8 Grid FluctuationWhen wires of a transformer grid branch is too long and there is large power equipment on the branch, the grid voltage will fluctuate sharply when the large equipment starts and stops. It even causes the grid to be unstable. When the grid voltage exceeds 310V, the drive may be damaged (even if there is an LED lightning protection device, it is useless. Because the lightning protection device is to deal with pulse spikes of tens of uS level, and the fluctuation of the grid may reach tens of mS, or even hundreds of mS) . Therefore, special attention should be paid when there is large electric machinery on the street lighting branch power grid. It is best to monitor the fluctuation range of the power grid or to supply power to the grid transformer separately. 1.9 Frequent Line TripsToo many lights are connected on the same branch, which leads to overload on a certain phase and uneven power distribution among the phases, resulting in frequent line trips. 1.10 Drive CoolingAlthough the LED has high luminous efficiency, only a small part of the energy flowing through the LED is radiated in the form of visible light. And most of the remaining energy is consumed in the LED in the form of heat, so the LED generates more serious heat. When the driver is installed in a non-ventilated environment, the driver housing should be in contact with the lamp housing as much as possible. If possible, apply thermal glue or a thermal pad on the contact surface between the housing and the lamp housing to improve the heat dissipation of the LED driver and ensure the reliability of the driver.Ⅱ LED Driver Maintenance2.1 Multimeter to Detect LED DriverMeasuring the output voltage of the no-load LED driver with a multimeter, if the output voltage is not detected, does it mean that the driver is broken? Look at the following steps:1) The voltage of the non-isolated LED power supply in the no-load state is about 300V tested with a multimeter, and it is about 220V with a PFC.2) Isolating the LED power supply, the voltage in the no-load state, tested with a multimeter, is about 3-5V more than the total voltage of the rated LED series. However, although the output voltage can be tested under no load, it does not mean that it can be normal under load. At this time, it is necessary to connect the corresponding LED light board to see the performance of the LED lighting. If there is no flicker, the output voltage is also equal to the total voltage of LED lights in series connection. This situation can be considered normal, otherwise it fails. If there is no output voltage at no load, the power supply must be broken. 2.2 Identify LED Power SupplyThe LED power supply is widely used in many applications. So how to distinguish the quality of LED power supply is particularly important. A few methods are briefly introduced below. LED Driver ICThe power of IC drive, the quality of IC directly affects the whole power supply. The lighting manufacturer should understand the IC design solution and calculate the cost of the driver, so as to purchase power products at a reasonable price. TransformersThe control chip can be regarded as the brain center of the power supply, while the transformers determine the power and temperature resistance. The transformer is responsible for the transfer of "AC to DC". However, the energy overload will damage the device. The core of the transformer is the magnetic core and the wire package. Electrolytic Capacitors and Ceramic CapacitorsThe quality and life requirements of input electrolytic capacitors are important. However, people tend to ignore the quality requirements of the output capacitor. In fact, the life of the output capacitor also has a great impact on the life of the power supply. The output end has a switching frequency of up to 60,000 times per second, which causes the parasitic resistance of the capacitor to heat up and produce substances similar to scale. Finally, the electrolyte heats up and bursts. Ceramic capacitors: The materials are divided into X7R, X5R and Y5V, and the actual capacitance value of Y5V can only reach 1/10 of the actual value. In addition, the nominal capacitance value only refers to when a capacitor works at 0V. Therefore, this tiny chip with poor options will also lead to a price difference in cost and greatly shorten the life of the power supply. Circuit Design and Welding ProcessJudgment of the pros and cons of the design: Aside from the professional point of view, it can be distinguished by some intuitive methods, such as the neat layout of the components, and soldering points. As for flying leads and manually adding components, it is a serious lack of techniques and efficiency. As we all know, the quality of mechanized production of wave soldering process is definitely better than manual welding. Because the machining process is more neat and uniform. Identification method: whether there is red glue on the back board.The flashing phenomenon of the lamp after a period of use is basically caused by the power supply or the weak welding of the lamp beads. However, it is extremely difficult to detect the virtual welding of products through aging, so AOI must be used to detect the quality of the power supply. Batch Inspection of Aging Racks and High Temperature Aging RoomsNo matter how good the power products are controlled by materials and production processes, they still need to be tested for aging. Because the incoming inspection of electronic components and transformers is difficult to control. Only through the aging of the entire batch of power supplies and the high temperature sampling inspection of the high temperature room. This is a wide-ranging screening to determine whether the materials have safety hazards. Ⅲ LED Driver Circuit ModulationThe LED driver circuit is divided into constant-voltage type and constant-current type according to the power supply to the LED. Constant-current switch type LED driver circuit samples the current flowing through the LED lamp, and gives the output control signal to control the on and off of the switching power tube, which aims to adjust the output current as the set value. The dimming control circuit mainly includes SCR dimming circuit, pulse width modulation (PWM), pulse frequency modulation (PFM), sliding mode control, PWM_PFM, PSM, etc. Let's take pulse width modulation (PWM), pulse frequency modulation (PFM), and sliding mode modulation to introduce in detail below. 3.1 Pulse Width Modulation (PWM)Pulse width modulation, shown in the figure below, refers to the stability of the output voltage by changing the on-time of the switching power tube in each cycle at a specific frequency. That is adjusting the duty cycle to obtain stable output voltage. When the output voltage changes due to the working environment, noise and other factors, the error amplifier samples the voltage change and sends the signal to the control circuit. The control circuit adjusts the duty cycle of the switching power tube signal to maintain the stability of the output voltage.Figure 4. PWM Modulation Based on BUCK StructureFigure 4 (a). Voltage ModeFigure 4 (b). Peak Current ModeFigure 4 (c). Average Current Mode3.1.1 Advantages of PWM(1) The PWM modulation method has high efficiency under heavy load, and has a good dynamic response to load changes.(2) The output ripple voltage is small and the linearity is high.(3) The frequency is stable, the duty cycle adjustment is not restricted, the control is simple, and both the current control mode and the voltage control mode are applicable.3.1.2 Disadvantages of PWM(1) The efficiency of PWM modulation method decreases at light load.(2) The transient response is slow during constant-voltage driving, and a more complicated compensation circuit is required.(3) Accurate current detection circuit is required for constant-current driving. 3.2 Pulse Frequency Modulation (PFM)The pulse frequency modulation is shown in the figure below. Under the condition of a certain on-time of the switching power tube, the output voltage can be controlled by adjusting the off time. When the output voltage changes, the error amplifier samples the feedback signal and sends the output signal compared with the reference signal to the control circuit. The control circuit analyzes the error signal and generates a square wave signal with constant pulse width and varying frequency to control the switch power tube to maintain the stability of the output voltage.Figure 5. Pulse Frequency Modulation Based on BUCK Structure3.2.1 Advantages of PFM(1) The PFM modulation has very high efficiency, better frequency characteristics and higher voltage regulation rate at light load.(2) The PFM modulation has a relatively high transmission signal-to-noise ratio and a good anti-interference ability.(3) The output voltage has a large adjustable range and low power consumption.3.2.2 Disadvantages of PFM(1) The efficiency of the PFM modulation will decrease under heavy load.(2) The frequency spectrum of the output ripple is scattered and irregular.(3) The load adjustment range is very small, resulting in high filtering costs. 3.3 Sliding-Mode ModulationSliding-mode modulation mode, the full name is sliding mode variable structure control,  is a discontinuous control. As shown in Figure 6, the sliding mode makes the system structure change purposefully according to its current state, which force the system to make small amplitude and high frequency up and down movements along the designed trajectory under response conditions. That is, sliding mode movement. Reduce the system's sensitivity to disturbances and load jumps.Figure 6. Sliding Mode Control Based on BUCK Structure3.3.1 Advantages and Disadvantage of Sliding ModeIt has the advantages of fast dynamic response, strong robustness and wide stability range, but it also has a problem that the operating frequency is not fixed. Ⅳ One Question Related to LED Driver4.1 QuestionHow long do LED drivers last?4.2 AnswerWhile the light function of an LED may last for years, drivers can give out much sooner. This is why we recommend name brand LED bulbs for the home, especially those with 25,000 hour rated lives. In general, high power white LEDs use much more current, and need of more complicated drivers. Frequently Asked Questions about LED Drivers Failure Analysis and Maintenance1. What is a LED driver IC?They are configured as either inductorless (charge pump) or switching regulator-based LED drivers that support driving white LEDs in series, parallel or combination. ... Topologies include boost regulator, buck regulator, buck/boost, SEPIC topology LED drivers, and more. 2. What is a LED driver used for?LED drivers are electrical devices that prevent damage to LEDs by regulating the forward voltage (VF) of the LED that changes with temperature, avoiding thermal runaway while delivering a constant current to the LED. LED drivers also aid efforts to meet new energy requirements (e.g., Energy Star). 3. How do I choose an LED driver?Use an LED driver with at least the same value as your LED(s). The driver must have a higher output power than your LEDs require for extra safety. If the output is equivalent to the LED power requirements, it is running at full power. Running at full power may cause the driver to have a shorter life span. 4. Why do LED drivers fail?LED FailureThe LEDs usually fail, because they have been connected to a constant LED driver in parallel. If the LEDs have failed you may want to also replace the LED driver. We usually recommend using a model with an adjustable output, and trimming down the output voltage slightly, to avoid over powering the LEDs. 5. How long do LED drivers last?Namely, the life of the driving circuit expires prior to when the LED stops emitting light or has its brightness dropped. The typical nominal lifetime of these elements is often times less than 25,000 hours, while the lifetime of LED itself could be as long as 50,000-100,000 hours. 6. Why do my LED drivers get hot?If the LED driver is trying to draw DC (not a balanced load circuit) then that can also cause the transformer to overheat.7. What is the difference between a transformer and an LED driver?LED drivers and electronic transformers for retrofit LED lighting are not interchangeable. They differ in output and load compatibility i.e. which LED lights they will work with. The fundamental difference between the two is that LED drivers output DC while electronic halogen transformers output 12VAC.