The Kynix Blog

IntoductionAn operational amplifier, or op-amp for short is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op-amp produces an output potential that is typically hundreds of thousands of times larger than the potential difference between its input terminals, and is a voltage amplifying device designed to be used with external feedback components such as resistors and capacitors between its output and input terminals. They are used extensively in signal conditioning, filtering or to perform mathematical operations such as add, subtract, integration and differentiation.In this video, the basic introduction of the Operational Amplifier (Op-Amp) has been given and different characteristics of ideal and real Op-amp (General Purpose 741 Op-Amp) has been discussed. CatalogIntroductionⅠ Operational Amplifier Basics1.1 Amplification Principle1.2 Balance Resistor1.3 Feedback Resistor in Parallel with a Capacitor 1.4 Pulling Down Resistor and Pulling Up the Capacitor1.5 Parasitical Resistor as an Integrator1.6 Parasitical Resistors and Capacitors1.7 Balance Resistor Failure1.8 Magnification, Input Impedence, Voltage1.9 Open Loop Gain1.10 Virtual ShortⅡ Op Amp ApplicationⅢ Op Amp SamplingⅣ Op Amp Reference VoltageⅤ Importance of Op AmpⅠ Operational Amplifier BasicsWhen using op amp, there will be more problems confusing us, what are they? Listing all of them is impossible, but we can seek the core of these problems, which are the following lists.1.1 Amplification PrincipleThere are many types of op amps with many functions, and their circuits are inconsistent, but the internal block diagrams are basically the same. It consists of three parts: input stage, intermediate stage, and output stage. The input stage consists of a differential amplifier circuit that uses circuit symmetry to improve overall circuit, and the main function of the intermediate voltage amplifier stage is to increase the voltage gain. It can be composed of one or more stages of amplifying circuits; the output stage has a voltage gain of 1, but can provide a certain amount of power, and the circuit consists of two power supplies V+ and V-. The entire amplifier circuit is designed with two inputs P and N, and one output O. The voltages of the three terminals are represented by Vp, Vn, and Vo, respectively. The two ends of P and N are respectively called the non-inverting input terminal and the inverting input terminal, which means that when the P terminal is added with the voltage signal Vp (Vn = 0), it is obtained at the output end. The voltage Vo is in-phase with Vp, when the voltage signal Vn (Vp = 0) is applied to the N terminal, the output voltage Vo obtained at the output is inverted from Vp.The operational amplifier is actually a differential amplifier. Look at its structure, two transistors are connected back to back to share the crossing current source. One of the transistors is the positive input of the op amp and the other is the inverting input. The positive input is amplified and sent to a power amplifier circuit to amplify the output. Thus, if the voltage at the forward input rises, the output naturally becomes larger. If the voltage at the inverting input rises, the reverse current is large, and the forward current is small, because the inverting tertiary tube and the forward tube share a same current source.1.2 Balance ResistorGenerally, there is a balance resistor in the inverting / non-inverting amplifier circuit. What is the role of this balance resistor?(1) Provide a suitable static bias for the transistors inside the chip.The internal circuit of the chip is usually directly coupled, and it can automatically adjust the static operating point, but if an input pin is directly connected to the power supply or the ground, its automatic adjustment function can not work normally. Because the voltage of the ground cannot be raised by the inside transistors, and the voltage of the power supply cannot be reduced, which causes the chip to fail to meet the conditions of virtual short and virtual open.(2) Eliminate the influence of the static base current on the output voltage, and the value should be balanced with the equivalent resistance value of the external DC of the two input terminals.(3) In non-inverting op amp circuit, if it not connecting a balance resistor, the op amp will be burned, because the resistor acts as a voltage divider. 1.3 Feedback Resistor in Parallel with a Capacitor What is the role of the feedback resistor in parallel with a capacitor when using non-inverting op amp?(1) The feedback resistor and capacitor form a high-pass filter, so that local high-frequency amplification is particularly noticeable.(2) Prevent self-excitation. 1.4 Pulling Down Resistor and Pulling Up the CapacitorWhat role does the role of pulling down resistor and pulling up the capacitor at the input of the op amp play?To get positive feedback and negative feedback, depending on the specific circuit connection. For example, if the input voltage signal and the output voltage signal are taken to the input, the partial output signal passes through the balance resistor to obtain a new voltage value, that is, shunting the input voltage to make the input voltage smaller, and this is a negative feedback. Since the signal output from the signal source is always constant, the output signal can be corrected by negative feedback. 1.5 Parasitical Resistor as an IntegratorWhat is the function of the resistor RF connected to the op amp as an integrator at the two ends of the integrating capacitor?Adjust resistance to prevent the output voltage from running out of control. 1.6 Parasitical Resistors and CapacitorsWhy are resistors and capacitors connected in series at the input of the op amp?Regardless of the type of op amp, it consists of transistors or MOS transistors. In the absence of an external components, the op amp is a comparator actually. When the voltage of the non-inverting terminal is high, it will output a level similar to the positive voltage, and vice versa, but this op amp does not seem to have much use. Only when the external circuit is formed to generate the feedback will make the real op amp function. 1.7 Balance Resistor FailureWhat is the consequence of the balance resistor doesn't work well in non-inverting amplifier circuit?(1) The non-inverting end is unbalanced. For example, there will be an output although the input is 0. When the input signal is output, the output value is always larger (or smaller) than the theoretical output value by a fixed number.(2) The error caused by the input bias current cannot be eliminated. 1.8 Magnification, Input Impedence, VoltageWhat is the amplification factor and input impedence of an ideal integrated operational amplifier? What is the voltage between the non-inverting input and the inverting input?The magnification is infinite, the input impedance is infinitesimal, and the voltage is almost the same (the voltage is not 0V, for example, the non-inverting end is 10V and the inverting end is 9.99V). 1.9 Open Loop GainWhy is the open loop gain of an ideal op amp infinite?1) The actual open loop gain of the op amp is very large, so imagine it as infinity and derive the virtual ground from it.2) Deriving virtual ground is not only an inverting amplifier for the negative feedback connection, because there is no virtual ground for positive feedback.The open-loop gain of the op amp is infinite, when design the circuit, the closed-loop gain can be independent of the open-loop gain, and only depends on the external components. It is to use the large open loop gain in exchange for the stability of the closed loop gain.3) Assuming that the gain is small, the difference between the voltages applied across the op amp is relatively large for an output voltage. If it is connected to a negative feedback state, the voltage across the op amp will be different, causing amplification.We all know that the op amp’s output voltage Vo is equal to the difference Vid between the non-inverting input voltage and the inverting input voltage, multiplied by the op amp’s open-loop gain A, that is, Vo = Vid * A = (VI + - VI-) * A ( 1 ). Since the output voltage of the op amp does not exceed the supply voltage in practice, it is a finite value. In this case, if A is large, (VI+ - VI-) is necessarily small; if (VI+ - VI-) is small enough, then we can actually treat it as 0, at this time,  there will be VI+ = VI-, that is, the voltage at the non-inverting input of the op amp is equal to the voltage at the inverting input. This is what we call “virtual short”. Note that they are not really connected together, and there is resistance between them.In the above discussion, how did we get the result of “virtual short”? Our starting point is the formula (1), which is based on the characteristics of the op amp. Then, we made two important assumptions, one is that the output voltage of the op amp is limited, and it not exceed the power supply voltage; the second is that the open loop gain A of the op amp is large. The A of a normal op amp usually reaches 106 or 107 or even larger, but the actual open loop gain of the op amp is also related to its working state. For example, if the op amp is not working in the linear area, the value A may be small, so second assumption is conditional.Therefore, we know that when the open loop gain A of the op amp is large, the op amp can have a virtual short. But it is one of the possibilities, and it is not suitable for every op amp in any case to say their inputs are virtual short, in other words, virtual short can only be achieved in circuits under certain conditions.The conditions of virtual short:a. The open-loop gain of operational amplifier should be large enough.b. There should be a negative feedback circuit. From the above we know when we need to analyze the virtual short in the circuit. In reality, condition (1) is true for most op amps, and the important point is to look at the work area. If it is a circuit drawing, judge by calculation; if it is an actual circuit, it is reasonable to use the instrument to measure amplifier output voltage.There is also a situation related to virtual short called “virtual ground”, that is, there is a virtual short when the input is grounded. Some books say that virtual short will be exist under deep negative feedback conditions, but in reality, the op amp is more likely to work in the linear region under this situation. But this is not absolute, when the input signal is too large, the op amp with deep negative feedback will still be saturated. Therefore, it should be judged to be the most reliable with the output voltage value. 1.10 Virtual ShortAdd the input signal directly to the non-inverting input, and the inverting input is grounded through the resistor. Why is U-= U+ = Ui≠0? Is it not a virtual short? What are the conditions that the virtual ground exists?(1) In the non-inverting amplifier circuit, the output affects by the feedback, so that U(+) automatically tracks U(-), so they will be close to zero. It seems that the two ends are short circuit, so it is called virtual short.(2) Due to the virtual short phenomenon and the high input resistance of the op amp, the current flowing through the two input terminals is small, approaching 0. This phenomenon is called virtual open, which is derived from virtual short.(3) The virtual ground is in the inverting op amp circuit, the (+) terminal is grounded, and the (-) is connected to the input and feedback network. Due to the virtual short, U(-) and U(+) are very close, which is said to be virtual ground.(4) About the conditions: the virtual short is an important feature of the closed-loop (negative feedback) operating state of the non-inverting amplifier circuit; the virtual ground is an important feature of the inverting amplifier circuit in the closed-loop operating state. Ⅱ Op Amp ApplicationWhen a operational amplifier is connected as a non-inverting amplifier, the potentials of the two inputs are the same. If the waveform of the input is measured, it will be the same. This is like a common-mode signal. In fact, there are still small differential mode signal on the two inputs, but the differential mode signal can not be measured by the general instrument. As a result, the virtual short artificially increases the common-mode signal at the two inputs, which poses a challenge to the performance of the operational amplifier. Why is an op amp used like this?(1) The common mode signal of the non-inverting amplifier is much larger than the inverting amplifier, and strict to the common mode rejection ratio.(2) For single-ended input, the equivalent common-mode value is half of the input value, whether non-inverting or inverting input. However, since the input impedance of the non-inverting amplifier is usually larger than the inverting amplification, the anti-interference ability is a little poor.As mentioned above, when the inverting input is performed, the voltage at the inverting terminal is almost zero, so the differential influence on the tube collector voltage that has only one tube change. When the input is in phase, the voltage at the inverting terminal is equal to the non-inverting terminal voltage, so the common mode voltage and the input voltage are equivalent. That is to say, the collector voltage of the differential tube has variable quantity that changes in the same direction when the two tubes have portions that change in different directions at the same time, which is the common mode output voltage. It is added in phase with the voltage of one of the tubes. Therefore, it is easy to cause the tube to become saturated (or cut off), fortunately, the amplification of the common mode voltage is only tens of thousands of parts of the differential mode amplification.However, this does not mean that the common mode rejection suppression ratio of the differential mode input and the common mode input of the amplifier is different. It should be that the non-inverting input is added with a common mode signal equivalent to the input volume, so it should be careful to use non-inverting amplification mode when the input signal is large. Ⅲ Op Amp SamplingWhy is the amplifier circuit composed of operational amplifiers generally sampling the inverting input mode?(1) The significant difference between the inverting input and the non-inverting input mode is:When inverting input, because there is a balanced resistor connected to the ground at the same phase, and there is no current on this resistor (because the input resistance of the op amp is extremely large), this non-inverting terminal is approximately equal to the ground potential, and  the potential at the non-inverting terminal is extremely close to the inverting terminal, so there is a virtual ground at the inverting end. The advantage of having a virtual ground is that there is no common mode input signal, even if the common mode rejection ratio is not high, there is no common mode output. The non-inverting input mode has no virtual ground. When a single-ended input signal is used, a common-mode input signal is generated. Even if an operational amplifier with a high common-mode rejection ratio is used, there is still a common-mode output. Therefore, it is best to use the inverting input method.(2) The positive phase is the oscillator, and the inverting can stabilize the amplifier and access the negative feedback.(3) From the principle point of view, it is possible to connect to the same analog circuit. However, the signal (differential mode signal) that is amplified during the actual application tends to be small, thus it is necessary to pay attention to suppressing noise (usually expressed as a common mode signal). In the same way, the amplification circuit has a poor ability to suppress the common mode signal, and the signal that needs to be amplified is submerged in the noise, which is not conducive to post processing. Therefore, an inverting proportional amplification circuit with better suppression capability is good.Ⅳ Op Amp Reference VoltageSome op amps will have an output even if no voltage is input after power-on, and the output is not small, so VCC/2 is often used as the reference voltage.The output is output signal without any input, this is called the input offset voltage Vos, which is caused by the asymmetry of the design structure of the op amp. It is a very important performance indicator of the op amp. The op amp commonly used VCC/2 as the reference voltage is because the op amp is in a single power supply state. At this time, the real reference of the op amp is VCC/2, so a DC offset of VCC/2 is often provided at the positive terminal of the op amp. When having positive and negative dual power supply, it is often referenced to the ground.The selection of op amps requires attention to many things. Under less stringent conditions, it is often necessary to consider the operating voltage, output current, power consumption, gain bandwidth product, and price of the op amp. Of course, when using it under special conditions, different factors must be considered in practice. Ⅴ Importance of Op Amp(1) If the voltage on both inputs of the op amp is 0V, the output voltage should also be equal to 0V. But in fact, there is always some voltage at the output, that is, the offset voltage Vos. If the offset voltage at the output is divided by the noise gain of the circuit, the calculated result is called the input offset voltage or the input reference offset voltage. The Vos is considered to be a voltage source in series with the inverting input of the op amp. A differential voltage must be applied to both inputs of the amplifier to produce a 0V output.(2) The input impedance of an ideal op amp is infinite, so no current flows into the input. However, a real op amp using a bipolar junction transistor (BJT) in the input stage requires some operating current, which is called bias current (IB). There are usually two bias currents: IB+ and IB-, which flow into the two inputs, respectively. The range of IB values is large, with bias currents of lower at 60fA for special op amps and up to tens of mA for some high-speed op amps.(3) The power supply voltage range required for the first single-chip op amp to operate normally is ±15V. Today, op amps are moving toward low voltages due to increased circuit speeds and power supplies from low-power sources such as batteries. Although the op amp’s voltage specifications are usually specified as symmetrical two-pole voltages ±15V, these voltages do not necessarily require a symmetrical voltage or a two-pole voltage. For an op amp, as long as the input is biased in the active region (within the common-mode voltage range), the ±15V supply is equivalent to a +30V/0V supply, or a +20V/-10V supply. The op amp does not have a ground pin unless the negative voltage rail is grounded in a single-supply application.The input voltage swing of high speed circuits is smaller than that of low speed devices. The higher the speed of the device, the smaller its geometry, which means the lower the breakdown voltage. Due to the low breakdown voltage, the device must operate at a lower supply voltage. Today, op amps typically have a breakdown voltage of around ±7V, so high-speed op amps can work at a supply voltage of ±5V, and they can also operate at a single supply voltage of +5V.For general-purpose op amps, the supply voltage can be as low as +1~8V. These op amps are powered by a single power supply, but this does not mean that a low supply voltage must be used. Because the terms single supply voltage and low voltage are two related and independent concepts. Frequently Asked Questions about Operational Amplifiers Problems1. How can you tell if an op amp is blown?Re: how to tell whether an op amp is burned out? measure the DC voltage at the +input. then measure the DC voltage at the output. if the results are significantly different, the opamp is most likely shot. 2. How do I know if my op amp is broken?measure the DC voltage at the +input. then measure the DC voltage at the output. if the results are significantly different, the opamp is most likely shot. if they are the same, the opamp is most likely ok and the problem is something else. 3. What errors you have to consider with real operation amplifiers?These errors include input bias current, input offset current, input offset voltage, CMRR, PSRR, and finite input impedance. In reality, all these errors will occur at the same time. 4. How do op amps fail?The common failures I have seen including with comparators involve either the output being shorted or open to one supply or the input differential pair or input protection circuits being damaged causing excessive input bias current and/or input offset voltage which usually ends up pinning the undamaged output. 5. Why do op amps fail?The common failures I have seen including with comparators involve either the output being shorted or open to one supply or the input differential pair or input protection circuits being damaged causing excessive input bias current and/or input offset voltage which usually ends up pinning the undamaged output.

Ⅰ What is a Crankshaft Position SensorⅡ Function and Location of Crankshaft Position SensorsⅢ How does a Crankshaft Position Sensor WorkⅣ Symptoms of a Bad Crankshaft Position Sensor4.1 Engine Vibrations4.2 Check Engine Light4.3 Weak Engine Performance4.4 Trouble Starting Car4.5 Engine Stalling4.6 Cylinder MisfiringⅤ How to Replace a Crankshaft Position SensorⅥ Frequently Asked Questions about Crankshaft Position Sensor Ⅰ What is a Crankshaft Position SensorThe engine, together with its components such as the crankshaft position sensor, is one of the most critical aspects of your car. Internal combustion engines are found in almost all modern cars. The crankshaft position sensor is responsible for keeping track of the engine's many moving parts, such as the crankshaft, valves, and pistons. It keeps track of the crankshaft's position and rotational speed, sending the data to the engine management unit so it can make modifications based on operating conditions. Engine management systems employ this information to govern fuel injection, ignition system timing, and other engine characteristics. On petrol engines, the distributor had to be manually set to a timing mark before electronic crank sensors were available. Video. Crankshaft Position Sensor Testing and Replacement Ⅱ Function and Location of Crankshaft Position SensorsThe crankshaft position sensor's primary function is to determine the crank's position or rotational speed (RPM). The information sent by the sensor is used by Engine Control Units to control factors like ignition and fuel injection timing. The sensor will control the fuel injection in a diesel engine. The sensor output may also be linked to other sensor data, such as the cam position, to determine the current combustion cycle, which is critical for a four-stroke engine's beginning. Figure1. Location of Crankshaft Position Sensor The crankshaft position sensor can be found in different places depending on the vehicle. It needs to be close to the crankshaft, therefore it's usually found on the engine's front underbelly. The timing cover is often where you'll find it mounted. It may be positioned on the engine's back or side. The clutch flywheel speed is sometimes used to determine the crankshaft speed using the crankshaft position sensor. The sensor is attached to the transmission's bell housing in these circumstances. Ⅲ How does a Crankshaft Position Sensor WorkThe teeth on the reduction ring attached to the crankshaft pass near to the sensor tip on the crankshaft position sensor. One or more teeth are missing from the reduction ring, which serves as a reference point for the engine computer (PCM). The sensor generates a pulsed voltage signal when the crankshaft spins, with each pulse corresponding to a tooth on the reduction ring. With the engine idling, the photo below displays the actual signal from the crankshaft position sensor. As you can see from the graph, the reduction ring in this vehicle has two missing teeth. Figure2. How a Crankshaft Position Sensor Works The PCM uses the signal from the crankshaft position sensor to determine when and in which cylinder to fire the spark. The signal from the crankshaft position is also utilized to check for misfires in any of the cylinders. There will be no spark and the fuel injectors will not operate if the sensor signal is missing. Magnetic sensors with a pick-up coil that produce A/C voltage and Hall-effect sensors that produce a digital square wave signal, as shown in the photo above, are the two most prevalent varieties. Hall-effect sensors are used in modern automobiles. A two-pin connector is found on a pick-up coil sensor. A three-pin connector is used to connect the Hall-effect sensor (reference voltage, ground, and signal). Figure3. Crankshaft position sensor signal Ⅳ Symptoms of a Bad Crankshaft Position SensorCrankshaft speed and position are critical elements in engine management calculations, and many engines will not start if the crankshaft position sensor does not provide an accurate signal. A malfunctioning crankshaft position sensor usually causes a few symptoms that alert the driver to a potential problem that needs to be addressed. 4.1 Engine Vibrations Figure4. Engine Vibrations Vibrations originating from the engine are another indicator of a malfunctioning crankshaft position sensor. Some people believe that when the engine is running, there is always some vibration emanating from under the hood. If you observe a significant increase in vibration, it could be due to an issue with the crankshaft position sensor. This vibration is frequently accompanied by a significant reduction in fuel economy and power. To get where you need to go, you'll need a lot more power and gas. 4.2 Check Engine Light Figure5. Check Engine Light The crankshaft position sensor is constantly communicated with by the engine control unit. If there is ever a problem with the sensor, the computer will receive incorrect information about the crankshaft's speed and location. This will cause engine malfunctions, resulting in the Check Engine warning light on the dashboard turning on. One of the first signs of a malfunctioning crankshaft position sensor should be this. P0335 is a typical error code that may appear. 4.3 Weak Engine Performance Figure6. Weak Engine Performance Your engine control unit will not know the right position of the crankshaft or cylinders if the crankshaft position sensor is damaged. This will cause the control unit's ability to maintain the engine's functioning and performance to be delayed. During this time, there will be moments of hesitancy every time you press harder on the gas pedal. It may or may not respond at all. On a road where you must move quicker without hesitating, this can be quite risky. 4.4 Trouble Starting Car Figure7. Trouble Starting Car Another major warning flag is that you are having trouble starting your vehicle. When you try to start your car, the crankshaft position sensor immediately starts measuring the crankshaft's position and speed. It receives a specific malfunction code from the sensor, indicating that there is an issue with its operation. When you try to start your vehicle while this problem is present, the engine will be more difficult to start. You may not be able to start your engine at all if the problem persists. 4.5 Engine Stalling Figure8. Engine Stalling One day, you may be cruising along when your engine suddenly stops running. When you have a defective crankshaft position sensor, this is known as engine stalling, and it can happen very frequently. If this sensor is not replaced soon, your engine will eventually stop working. You'll have no choice but to have your car towed to a repair to have the sensor changed. 4.6 Cylinder Misfiring Figure9. Cylinder Misfiring If the crankshaft position sensor fails, the engine control unit will not be able to reliably communicate data about the piston position. A misfire in one or more of the chamber cylinders is common as a result of this. A faulty spark plug can also cause this, but if you're experiencing any of these additional symptoms, don't discount out a bad crankshaft position sensor. Ⅴ How to Replace a Crankshaft Position SensorStart by looking for the sensor, which you can do by inspecting the engine and looking for any sensor that matches the new sensor you just bought at the lower level. Materials:shop lightcarburetor cleanerplastic clipcleaner Tools:small wrench or socketsmall pick or standard screwdriver Step1 Disconnect the BatteryIt's a good idea to disconnect the battery whenever you're working on the engine's inner workings to avoid a short circuit in the car's electrical system. Remove the disarm plug for the main battery pack on hybrid vehicles as well. The location can be found in your owner's manual. Figure10. Disconnect the Battery Step2 Clear Access to the SensorThis crank sensor is located behind the starter motor, which must be removed to access the sensor. When working beneath the car, use a shop light to see what you're doing. Figure11. Clear Access to the Sensor Step3 Inspect the Sensor LocationBecause of the transmission cooling lines, this sensor is difficult to notice, although it is located on the side of the block with the electrical connector attached. If the crankshaft angle sensor is oily, this is a good opportunity to clean it out with a small bit of carburetor cleaner to get a fresh start on the work. Figure12. Inspect the Sensor Location Step4 Release the Electrical ConnectorA plastic clip will hold an electrical hookup to the sensor, which you must push down or pull outward to disengage. Wiggle the connector away from the sensor gently once this is done. This connector can become stuck due to the weather pack seal, which helps keep water out of the sensor terminals, causing corrosion. After removing the connector, inspect it for rust and clean or replace the pigtail if necessary. The engine will stall due to this issue alone. Figure13. Release the Electrical Connector Step5 Remove the Sensor Mount BoltThe majority of crankshaft sensors only have one mounting bolt, which is usually a 10mm bolt. Remove the bolt with a tiny wrench or socket by rotating it counterclockwise and storing it to the side. Figure14. Remove the Sensor Mount Bolt Step6 Remove the SensorBecause the crank sensor has a long stem that can get jammed in the block, removing it can be difficult. To push the sensor mounting tab away, insert a small pick or a regular screwdriver beneath it. Applying too much pressure on these sensors can lead them to break, leaving a piece of the sensor inside the block. When this happens, you can either press the broken piece inward so it falls into the oil pan and stays there, or you can remove the oil pan and remove the broken piece. Figure15. Remove the SensorOnce the sensor is free, take a firm grip on it and twist it away from the engine block. On the sensor, there will be a sealing O ring that will need to be replaced with the new sensor. A new O ring is included with most new sensors. Figure16. Old Crankshaft Position Sensor Step7 Match the New Crankshaft SensorWipe away any grease from the old sensor so you can notice any design differences in the new sensor. When installing new sensors, such as mounting tabs, minor design adjustments are common. The length of the sensor stem can be variable because if it is too long, it will contact the crankshaft, and if it is too short, it will not read accurately. Figure17 .Match the New Crankshaft Sensor Step8 Installing the New Crank Position SensorClean the position sensor porthole with a shop towel before inserting the new sensor to ensure a proper seal to the new sensor O ring. Because there will be motor oil in this port, do not spray carburetor cleaning within it. To help with the cleaning, spray cleaner on the shop towel. Figure18. Sensor Port Place the new crank sensor in the sensor port hole squarely and firmly while matching the mounting plate hole with the threaded bolt hole in the block. Then, by hand, thread in the mounting bolt by turning it clockwise to avoid cross-threading. To avoid damaging the O ring seal and causing an oil leak, lube it with a tiny amount of clean engine oil or WD40. Thread the mounting bolt into place once the sensor has been placed and tighten to around 2-3 foot-pounds. Figure19. Install New Cranks Angle Sensor Push the electrical connector into position while listening for a click to indicate that it has been properly placed and is ready to use.Figure .Install Crankshaft Angle Sensor Connector Step9 Reconnect the BatteryWhen you're done, take the car off the jack stands and rejoin the negative battery cable, and you're ready to go. Figure20. Reconnect the Battery Ⅵ Frequently Asked Questions about Crankshaft Position SensorHow much does it cost to replace a crankshaft position sensor?The average cost for crankshaft position sensor replacement is between $178 and $226. Labor costs are estimated between $98 and $123 while parts are priced between $81 and $103. How long does it take to replace crankshaft sensor?The engine still may run poorly, either way find a good mechanic, one who specializes in engine performance, and set an appointment – the sooner the better. In most instances, this repair should take no longer than one day. Does a crankshaft sensor have to be programmed?No, they do not have to be programmed. After the replacement you should cancel the code and see if it comes back. What happens if you don't relearn crankshaft position sensor?Failure to do such will result in over revving of the engine, causing possible engine damage. 8. Once the engine has returned to idle, check the status of Diagnostic trouble code P1336. If the scanner indicates that the CASE has been learned, the relearn procedure is now complete. 

CatalogⅠ What is a Zener Diode?Ⅱ What is the Zener diode symbolⅢ Zener Diode Circuit DiagramⅣ How Does a Zener Diode Work?Ⅴ How to Test a Zener Diode?Ⅵ Differences in Avalanche Breakdown & Zener BreakdownⅦ V-I Characteristics of Zener Diode7.1 Forward Characteristics7.2 Reverse CharacteristicsⅧ Zener Diode AdvantagesⅨ Zener Diode DisadvantagesⅩ Avalanche Breakdown vs Zener Breakdown Ⅺ Applications of Zener DiodeⅫ Zener diode as voltage regulatorFrequently Asked Questions – FAQsIntroductionThe Zener diode symbol is extremely similar to that of a standard p-n junction diode, with the sole variation being bent edges on the vertical bar. The Zener diode sign is made up of anode and cathode terminals. The anode terminal is the +ve terminal, whereas the cathode terminal is the -ve terminal. It works in both directions, forward bias and reverses bias. It is mostly used in reverse bias mode.When reverse biased, ordinary silicon diodes stop all current and are destroyed when the reverse voltage is too high. As a result, these diodes are never deliberately driven in the failure area.Zener diodes, on the other hand, are unique. They are precisely built to perform without fail in the breakdown zone. As a result, Zener diodes are sometimes known as breakdown diodes.Ⅰ What is a Zener Diode?A Zener diode is a form of PN junction diode that can conduct both forward and reverse current. It contains strongly doped areas and is mostly utilized to conduct current in reverse. When the reverse voltage crosses a particular limit known as the reverse breakdown or Zener breakdown voltage, it begins to conduct in the other way.A Zener diode, unlike a regular diode, can and is particularly engineered to function in the reverse breakdown zone. During the breakdown area, the voltage across the device remains constant while the current changes.Specifications of Zener DiodeBreakdown Voltage: The breakdown voltage varies between 2.4 and 200 volts.Current (max) Iz: This is the maximum current at the rated Zener Voltage, with Vz ranging from 200 micro-Ampere to 200 Ampere.Current Iz (min): The smallest current amount is necessary for diode failure.Power Rating: This is the maximum power that the diode can consume. It is the voltage and current flowing through the diode.Temperature Stability: 5V is necessary for the optimum temperature stability of diodes.Ⅱ What is the Zener Diode SymbolElectric current passes from anode to cathode and cathode to anode in a Zener diode. The Zener diode symbol is identical to the standard p-n junction diode symbol, but with bend edges on the vertical bar.Symbol of Zener diode in the circuit diagramZener diode symbolⅢ Zener Diode Circuit DiagramThe Zener diode circuit diagram is given in the image below. In reverse biased, a Zener diode is used. Reverse biasing implies connecting the diode's n-type material to the positive terminal of the supply and the P-type material to the negative terminal of the supply. Because the diode is comprised of strongly doped semiconductor material, the depletion area is quite narrow.Ⅳ How Does a Zener Diode Work?When used in a circuit with forwarding bias, the Zener diode behaves like any other diode. When the circuit is reverse biased, the current is halted until the Zener voltage is reached. This property is significant because it allows for reliable voltage management while carrying large currents. The Zener voltage may be fine-tuned by doping the device as required.Although the current-voltage (I-V) curve of a Zener diode resembles that of an ordinary p-n junction diode, there are three distinct zones in the I-V characteristic curve of a Zener diode.Fig. 2. Zener diode I-V characteristic curve and the circuit diagram for a voltage regulator using a Zener diode The forward bias area is defined as the region where the applied voltage is forward biased and the device permits forward bias current to flow. The applied voltage is reverse biased in the reverse bias zone, as is current flow, which considerably rises in the breakdown region after the applied voltage surpasses the Zener voltage.There are three distinct phenomena involved in the workings of a Zener diode.In the reverse bias voltage, Zener breakdown happens before avalanche breakdown. A Zener breakdown happens when electrons quantum tunnel over the depletion region of a diode, whereas an avalanche breakdown occurs when minority carriers in the depletion zone strike other atoms to form new carriers.The breakdown voltage in the diode where the reverse bias current occurs is referred to as the Zener voltage. The threshold voltage is the point at which the applied electric field becomes high enough to give the energy required for electrons to quantum tunnel through an otherwise prohibited location.In general, Zener diodes are beneficial in circuits with reverse bias. A Zener diode acts like any other diode in the forward bias condition.Ⅴ How to Test a Zener Diode?Figure 2 also depicts a basic design for a Zener diode in a voltage regulator. This circuit arrangement may be used to test and determine the Zener voltage characteristic of the device. An input voltage is placed across the Zener diode, and the load resistor is probed using a voltmeter or a similar device to measure the output Zener voltage. The resistor linked in series with the voltage input controls the input current. The voltage measured across the load is the Zener voltage. Assuming that the reverse bias current does not exceed the device's thermal limitations, the diode can carry a significant current while maintaining a steady voltage across a load.Ⅵ Differences in Avalanche Breakdown & Zener BreakdownAvalanche breakdown is caused by collisions between electrons in the depletion area, whereas Zener breakdown is caused by a high electric field.In weakly doped P-N junction diodes, avalanche breakdown occurs, whereas in substantially doped P-N junction diodes, Zener diode occurs.The diode cannot resume its initial position following the avalanche breakdown, but it can regain it following the Zener breakdown.In the case of Zener breakdown, the electric field in the depletion zone is greater than in the case of avalanche breakdown.Avalanche breakdown produces both pairs of holes and electrons, whereas Zener breakdown produces solely electrons owing to a strong electric field.Avalanche breakdown is caused by a high reverse voltage, whereas Zener breakdown is caused by a low reverse voltage.Avalanche breakdown has a positive temperature coefficient, which means it grows as the temperature rises, whereas Zener breakdown has a negative temperature coefficient, which means it drops as the temperature rises.When contrasted to the avalanche breakdown, theZener breakdown has a strong curve in its V-I properties.Ⅶ V-I Characteristics of Zener DiodeThe V-I characteristic, also known as the Volt-Ampere characteristic, is a graph that depicts the change in current as a function of the voltage applied across the junction. The Zener diode's V-I characteristics are classified into two types: forward characteristics and reverse characteristics. Let us go through them in depth.7.1 Forward CharacteristicsThe Zener diode's forward-biased properties are seen in the first quadrant of the graph above. The graph clearly shows that the forward-biased properties of the Zener diode are the same as those of a typical P-N junction diode, i.e., increasing the voltage surrounding the terminal increases the current flowing through the circuit. However, due to the increased doping concentration in the Zener diode, the amount of current flowing through it is more than that of a typical P-N diode.7.2 Reverse CharacteristicsWhen the Zener diode is reverse-biased, only a small amount of leakage current flows through the circuit at first due to minority charge carriers generated thermally, but when the applied reverse voltage is increased further to a certain value of reverse voltage, the breakdown occurs, and a sharp increase in reverse current is observed. The Zener voltage (Vz) is the value of the reverse voltage where the breakdown has occurred, and the Zener Effect is the breakdown effect. The current traveling through the Zener diode may be limited using external resistance. The voltage (V) flowing through the diode may be estimated quantitatively using the formula,V=Vz+IzRzWhere Vz is the Zenere breakdown voltage, Iz is the Current flowing through the Zener diode, and Rz is the Zener resistance.Ⅷ Zener Diode AdvantagesThe Zener diodeis inexpensive.It keeps the input voltage stable and adjusts it.It features a straightforward circuit and is very compatible.It is commonly used to safeguard electronics against overvoltages in electrical circuits.At the output terminal, it delivers a constant voltage.It is capable of controlling the excess current flow in the circuit.It functions as a waveform clipper.Ⅸ Zener Diode DisadvantagesThe Zener diodeapplies even more reverse voltage to balance out the excess input voltage, which wastes a lot of power in the process.Because their efficiency decreases at large load currents, Zener diodes are not suited if the load current is too high.The output voltage varies somewhat due to Zener resistance.The circuit has a high internal impedance.For regulating voltages, transistors are preferable over Zener diodes because they have a higher regulation ratio.We cannot alter the output voltage since the Zener voltage equals the output voltage (Vo=Vz).Ⅹ Avalanche Breakdown vs Zener Breakdown The key differences between Avalanche Breakdown and Zener Breakdown are tabulated below:ParametersZener BreakdownAvalanche BreakdownDefinitionIt occurs in the Zener diodes having Vz between 5 to 8 volts or less than 5V.Avalanche breakdown occurs in the p-n junction when the Vz is greater than 8 volts.Depletion regionThe depletion region is thin.The depletion region is thick.Electric connectionThe connection is not destroyed.Connection is destroyed.Electric fieldThe electric field is strong.The electric field is weak.Temperature coefficientNegativePositiveVoltage proportion to the temperatureInversely proportionalDirectly proportionalStructurePN junction diodeHighly developed p and n regionⅪ Applications of Zener DiodeThe major applications of Zener diodes are the following:Clipper circuitsVoltage shiftingVoltage regulationOver-voltage protectionⅫ Zener Diode as Voltage RegulatorA voltage regulator aims to maintain a constant load voltage despite variable load current and supply voltages. In the case of Zener diodes, the Zener voltage provides voltage control. In reverse conducting mode, the Zener diode maintains a constant voltage across its terminal while altering the current flow through it. As a result, the voltage across the parallel load remains constant.CONCLUSIONWhen forward-biased, a Zener diode functions as a simple diode (on).When reverse-biased up to Zener Voltage, a Zener diode can serve as a switch (off) (VZ).From Zener Voltage (VZ) until Avalanche Breakdown, the output of a Zener diode is nearly constant and equals Zener Voltage (VZ).A minor change in input voltage induces a quick increase in Zener Current (IZ) while operating in Zener mode, which can be reduced by employing a series resistor (RS).Power supply, voltage regulators, protective circuits, and waveshapers are the most typical applications for Zener diodes.It is usually suggested to study a Zener diode's datasheet before using it to determine its rated characteristics as per design requirements.Frequently Asked Questions – FAQs1. How do you define Zener diode?A Zener diode is a semiconductor device that permits current to flow in either the forward or backward direction.2. Why is Zener Diode used as a regulator?A Zener diode is used as a shunt voltage regulator. The Zener diode is connected in parallel to the load to reverse bias it, and after the Zener diode exceeds the knee voltage, the voltage across the load becomes constant.3. Does Zener Diode exhibit a controlled breakdown?Yes, a controlled breakdown occurs in a Zener diode.4. What is the difference between a Zener diode and a normal diode?The flow of current is what distinguishes a Zener diode from a regular diode. A typical diode enables current to flow in just one direction, but a Zener diode allows current to flow in both directions.5. What is Zener Breakdown?The Zener breakdown is caused mostly by a strong electric field. When a strong electric field is placed across a PN junction diode, electrons begin to flow across the PN junction. As a result, the little current in the reverse bias grows.6. What is differenece between Zener Diode and normal P-N junction diode?The primary distinction between a typical P-N junction diode and a Zener diode is that the former allows current to flow only in one direction, whilst the latter permits current to flow in both directions.7. Does a Zener Diode symbol have a circle?The circle is an optional style that was popular in the past, but diodes are now typically drawn without it.

CatalogIntroductionⅠ The Types of Disc relayⅡ Principle of Induction Disc RelayⅢ Induction-Disc RelayⅣ Advantages of Induction Disc RelayⅤ Applications of Induction Disc RelayⅥ How you Should Test an Induction Disc Relay’s PickupⅦ REDI – TM64 – Electronic Disc RelayⅧ The Difference Between a Reverse Power Relay and a Watt Hour Induction Disc RelayFAQIntroductionA disc relay is a form of electromagnetic relay that operates on the concept of electromagnetic induction and looks similar to a split-phase induction motor. The interaction of fluxes shifted in time and space in the rotor will produce the operating force (movable element). This article goes over disc Relay in further detail.Electromagnetic Induction Disc Relay Ⅰ The Types of Disc relayThe majority of relays are used to protect wires and equipment. There are two types of induction relays: induction disc relay and induction cup relay.Ⅱ Principle of Induction Disc Relay Induction disc relays, like induction motors, work on the principle of electromagnetic induction. The interaction of alternating flux with one of the magnets and eddy currents induced in the rotor (disc) with the other alternating flux produces torque in these relays. Both fluxes have the same frequency, but there will be a phase delay between them. As a result, these relays can only be used on alternating current circuits. The moving element of this relay is a disc to which the relay's moving contact is fixed.Induction disc relays are of two types. They are,Induction relay with shaded poles,Induction relay of the Watt-hour meter variety.Ⅲ Induction-Disc RelayThis was originally employed in the design of electro-mechanical energy meters and was used in the basic implementation of an overcurrent relay. An aluminum disc revolves between the poles of an electromagnet, producing two alternating magnetic fields that are phase and space-separated. The eddy currents generated by one flux and the remaining flux interact to generate a torque on the disc. The flux displacement in early relays was produced by a copper band wrapped around a portion of the magnet pole (shading ring), which displaced the flux contained by it. As seen in Figure 11.14, later designs of these electromechanical relays used a watt metric principle with two electromagnets.Figure 11.14 Induction-disc relayThe lower electromagnet's current is induced by transformer action from the higher winding, resulting in sufficient displacement between the two fluxes. This, however, can be modified by connecting a reactor to the secondary winding.The phasor diagram in Figure 11.15 depicts the basic method of action of the induction disc. The torques produced are proportional to F2ij sin a and Fj i2 sin a, hence the total torque is proportional to Fj F2sin an or q i2sin a because F: is proportional to q and F2 is proportional to i2.Figure 11.15 Operation of disc-type electromagnetic relay, (a) Fluxes, (b) Phasor diagram. i1 and i2 are induced currents in discThis relay is powered by a current transformer (CT), and the sensitivity can be adjusted using the connector arrangement shown in Figure 11.14. The time it takes for the contacts to close is changed by altering the angle at which the disk must rotate.Figure 11.16 depicts the operational characteristics. To employ a single characteristic curve for all relay sensitivities (plug settings), a parameter known as the current (or plug) setting multiplier is used as the abscissa rather than the current magnitude, as shown in Figure 11.16. The time multiplier changes the angle at which the disk rotates, translating the curve vertically.Figure 11.16 Time-current characteristics of a typical induction disc as a function of plug-setting multiplier. TMS stands for time multiplier setting.Inverse Definite Minimum Time is the name given to this relay characteristic (IDMT). The operating characteristic of a conventional IDMT relay is defined as:TMS: Time Multiplier Setting PSM: Plug Setting MultiplierThe following example shows how to use this curve (which is often displayed on the relay casing).Example 11.1Calculate the operating period of a 1 A, 3 s overcurrent relay with a Plug Setting of 125 percent and a Time Multiplier of 0.6. The supplying CT has a 400:1 A rating, and the fault current is 4000 A.SolutionThe fault relay coil current = (4000/400) x 1 = 10 A. The nominal relay coil current is 1.25 A (1 x (125/100). As a result, the relay fault current multiplied by the Plug Setting = (10/1.25) = 8 (Plug Setting Multiplier). The time of operation is 3.3 seconds for a time setting of one, according to the relay curve (Figure 11.16). The time multiplier (TM) regulates the operating time by adjusting the angle at which the disc rotates to seal the connections. 3.3 x 0.6 = 2.0 s is the actual operation time. This can be calculated simply from the equation (11.1)as: Induction-disc relays can be made sensitive to real power flow by feeding the upper magnet winding in Figure 11.14 from a voltage and the lower winding from the equivalent current via a potential transformer. Because the top coil has a large number of turns, the current lags the applied voltage by 90°, whereas they are practically in phase with the bottom (small number of turns) coil. As a result, Fj is proportional to V, F2 is proportional to I, and torque is proportional to FjF2 sin a, or VI sin (90 — a) or VI cos a. (where a is the angle between V and I).The torque direction is determined by the power direction, hence the relay is directional. A power relay combined with a current-driven relay can give directional overcurrent protection.Ⅳ Advantages of Induction Disc Relay Induction disc relaysare well-built devices.Under abnormal situations, the operation of the induction disc relay can be easily controlled by simply opening the secondary coil.The current and time settings can be easily obtained by employing induction disc relays.Induction disc relays are dependable and precise.They can be used to defend against overcurrent.Ⅴ Applications of Induction Disc Relay Inductiondisc relays are utilized where dependability and robustness are required.These relays have a wide range of applications where slow-speed relays are required.When an adjustable operating time and time-delay feature is required, induction disc type relays are used.This relay is utilized when a high reset to pick-up ratio is required.Ⅵ How you Should Test an Induction Disc Relay’s PickupTechnically, you should set the relay to the particular specifications provided in the instruction manual, but doing so has the following drawbacks:They are contradictory, which indicates that various processes are required for different models.They are impracticable for maintenance testing since they require changing the settings and do not demonstrate that the relay is operational at the in-service settings.They do not permit automatic control for more trustworthy results in the absence of external equipment.Two distinct testers will almost certainly produce two different test results.Use the standard test procedure most testers, and automated test software, perform so that:On all relays, everyone follows identical processes.You will be responsible for ensuring that the relay is operated under normal operating conditions.The test findings can be automated.Different relay tests are more likely to produce consistent results across maintenance periods.After all, that's what all the cool relay testers are already doing.Ⅶ REDI – TM64 – Electronic Disc RelayThe REDI-TM64 is an electronic disk relay designed to replace old electromechanical relays and the most recent electronic disk relays. The REDI-TM64 is built on a 2o2 microcontroller architecture in diversity, which ensures SIL4 safety. The function of disk relays is to certify the track circuit occupancy status (BTC), that is, to signal whether a train is traveling over a specific rail section. This is accomplished by comparing the amplitude, phase, and frequency of two electrical impulses (local voltage and national voltage).The existence of real-time microcontrollers enables measurements with a high sample frequency and high accuracy, as well as evaluating the status of the track circuit correctly and safely, even in the presence of large traction current disturbances. A powerful software technique reduces distortion, noise, and disturbance components, resulting in REDI intervention in under 100mS.The REDI-TM64 has a user interface that allows the device to be customized in the field (power factor correction using a user-configurable offset, self-reflection adjustment) and displays the device's most important parameters (presence of PSK modulation, track circuit status, etc.).External devices (capacitors) are not required to correct for any phase shift in the field by the REDI-TM64.The RFI specification DTCDNSSSTB SR IS 21 028 C is met by the REDI-TM64.The REDI-TM64 provides SIL4 safety according to CENELEC standards 50126, 50129, and 50128.Ⅷ The Difference Between a Reverse Power Relay and a Watt Hour Induction Disc RelayWhat is the difference between a reverse power relay and a watt hour induction disc relay?Both are disk-type meter relays that are used in large-scale ring feeds to isolate one city from the rest in the case of a catastrophic fault. They operate at staggered intervals and monitor overcurrent and reverse power.FAQ1. What is directional relay?Overcurrent relays in the power system respond to excessive current flow in a certain direction. The relay is typically made up of two components. A directional element, for example, determines the direction of current flow in relation to a voltage reference.2. Why directional relay is used?On buses with two or more sources, directional overcurrent relays are typically utilized on incoming line circuit breakers. They are wired to trip an incoming line breaker to let fault current flow back into the source, ensuring that a failure on one source does not feed the other sources.3. What is the difference between SSR and relay?The distinction between Solid State Relays (SSRs) and Mechanical Relays Solid state relays, or SSRs are a form of relay that may be found all over the world. The fundamental distinction between solid-state relays and ordinary relays is that solid-state relays do not have moveable contacts (SSR).

body { font-family: Arial, sans-serif; line-height: 1.6; color: #333; } h2 { border-bottom: 2px solid #3598db; padding-bottom: 10px; margin-top: 30px; } h3 { color: #2c3e50; margin-top: 25px; } img { max-width: 100%; height: auto; } .note { background-color: #f9f9f9; border-left: 5px solid #3598db; padding: 15px; margin: 20px 0; } .faq-item { margin-bottom: 20px; } .question { font-weight: bold; font-size: 16px; color: #236fa1; }IntroductionThe Q factor (quality factor) serves as a critical metric telling us how close a real-world inductor is to an ideal inductor. Inductors are ubiquitous components in power electronics converters, filter networks, and communication systems, where they are frequently used in resonant networks. While theoretical studies often treat inductors as having pure inductance, in reality, they possess inherent resistance and parasitic elements. The Q factor is defined as the ratio of the inductive reactance of the coil to its effective resistance.While the most obvious constituent of this resistance is the standard DC resistance (DCR) of the wire, high-frequency AC losses often play a more significant role. So, what is the true relationship between resistance and quality factor? Why is the Q factor so vital?Video: What is Q-Factor?Ⅰ Why is Q Factor Important for an Inductor?When selecting components, engineers must rely on the manufacturer's datasheet and product line cards after calculating the required inductance for the specific application. However, the Inductance value alone is not enough. It is crucial to consider the Quality Factor (Q) of the inductor, particularly for RF (Radio Frequency) circuits and precision analog applications.A high Q factor indicates that the inductor has low energy losses relative to the energy it stores. In resonant circuits, a high Q leads to a sharper resonance peak and narrower bandwidth, which is essential for selectivity in radio tuners. In power applications, a higher Q generally implies lower power dissipation (heat), leading to higher overall system efficiency.Ⅱ Inductor Q Factor Analysis2.1 There Are No Ideal InductorsIn practice, a "perfect" component does not exist. Inductors are constructed by winding conductive coils around cores made of various magnetic materials (ferrite, iron powder, air, etc.). The actual inductance value depends on physical parameters: the number of turns, the permeability of the core material, flux density, and the core's cross-sectional area.Furthermore, in real-world operation, the effective inductance and performance can fluctuate based on the applied current (saturation), signal frequency, aging, and operating temperature. To ensure consistent output accuracy across a wide range of frequencies and environmental conditions, specific parameters must be quantified. The Q-Factor is the primary parameter used to measure the "purity" and consistency of the coil's performance.2.2 What is Q-Factor?Figure 1. Q Factor in InductorsIdeally, an inductor would only exhibit inductance. However, a functional inductor includes fixed DC resistance, variable AC resistance, and parasitic capacitance. These parasitic elements reduce the inductor's efficiency. The Quality Factor (Q) is a dimensionless figure of merit that quantifies the inductor's performance regarding its losses. It is essentially the ratio of Energy Stored to Energy Dissipated per cycle.Let's explore the parasitic resistances that lower the Q Factor in depth:(DCR or RDC) DC ResistanceThe wire used to wind the coil has internal resistance, known as "DC resistance." This value is usually found in the "DCR" or "RDC" column of a datasheet. DCR depends on the total length of the wire and its cross-sectional area (gauge). To achieve a higher inductance, more turns are required, which increases wire length and, consequently, DCR. Designers often have to balance wire thickness and physical size. Larger diameter wires (lower gauge number) yield lower DC resistance but increase the component's size.Note: How to calculate the resistance of copper wire?Engineers often use the standard resistivity formula:Where:R is the resistance in Ohms (Ω)l is the length of the conductor in metersρ is the electrical resistivity of the material (e.g., Copper)A is the cross-sectional area in square millimeters (derived from wire diameter)Skin Effect Due to AC Resistance (Rac)When the frequency increases (roughly above 50 kHz for standard copper wire, though the effect starts earlier), AC resistance (Rac) becomes dominant over DCR. This is due to the "Skin Effect."At higher frequencies, alternating current tends to flow only near the surface (or "skin") of the conductor rather than through the entire cross-section. This effectively reduces the usable cross-sectional area of the wire, significantly increasing resistance. To mitigate this in high-Q applications, engineers often use Litz wire (multistrand insulated wire) to increase surface area.Core Hysteresis Losses (Modeled as Resistance)In magnetic cores, the magnetic domains must align and realign with the changing magnetic field (H). This realignment is not frictionless; energy is lost as heat during each cycle. This is known as Hysteresis Loss. Ideally, the B-H curve (Magnetic Flux Density vs. Magnetic Field Intensity) would be linear. In reality, it forms a loop. The area inside this loop represents energy lost per cycle.As frequency increases, these losses occur more often per second, increasing the effective resistance. This loss appears in the equivalent circuit as a resistor in series (or parallel, depending on the model) with the inductor, lowering the Q factor.Figure 2. BH Curve and Hysteresis LoopDielectric Losses (Rd)Inductors use insulation on the wire (enamel) and sometimes between layers. The core material itself is also a dielectric. These materials have finite resistance and dielectric constants. While often modeled as a parallel resistance (leakage), dielectric absorption causes losses that add to the total system energy loss, further reducing the Q factor at very high frequencies.Calculating Total Resistance and QThe total effective series resistance (ESR) in a functional inductor is the sum of these components:The Quality Factor (Q) is calculated as the ratio of Inductive Reactance ($X_L$) to this Total Resistance ($R_{total}$):Where $ \omega = 2\pi f $ (frequency).The Q factor can also be expressed in terms of power:Conclusion: If DCR, Skin Effect, or Core Losses increase, the denominator ($R$) increases, causing the Q-Factor to drop. A lower Q means higher power loss and broader bandwidth. Conversely, a high Q value implies that the inductor behaves more like an ideal reactance with minimal energy loss.Ⅲ What is the Role of Q Factor in a Circuit?The Q factor plays a dominant role in the **Filter Bandwidth** of practical circuits.Narrow Bandwidth (High Q): For Radio Frequency (RF) applications—such as police wireless communication or distinct radio channels—filters must be highly selective. They need to accept a specific frequency while rejecting everything else. An inductor with a High Q factor (Red line in theoretical plots) produces a sharp resonant peak, allowing for a narrow bandwidth.Wide Bandwidth (Low Q): Other applications may require a wider frequency range to pass through. An inductor with a lower Q factor (Orange line) produces a flatter, broader curve with less voltage gain at the peak but a wider passband.Additionally, designers must remember the Self-Resonant Frequency (SRF). Every inductor has parasitic capacitance between its windings. At a certain high frequency (SRF), the inductor resonates with its own capacitance and acts as a resistor. Beyond this frequency, it behaves like a capacitor, and the Q factor concept as an inductance metric becomes invalid.Frequently Asked Questions about Q Factor in Inductors1. How do you find the Q factor of an inductor?The quality factor Q of the inductor is defined by the formula $Q = \frac{\omega L}{R}$, where $\omega$ is the angular frequency ($2\pi f$), $L$ is the inductance, and $R$ is the effective series resistance (ESR). Since $R$ changes with frequency (due to skin effect and core losses), Q is frequency-dependent. It is usually measured using an LCR meter or an Impedance Analyzer at the specific operating frequency of the circuit.2. How is Q factor calculated from a bandwidth perspective?In a resonant circuit, the Q factor can be determined by the frequency spectrum. It is defined as $Q = \frac{f_r}{\Delta f}$, where $f_r$ is the resonant frequency (where impedance is maximum or minimum depending on circuit topology) and $\Delta f$ is the -3dB bandwidth (the width of the peak at half-power). A narrower peak indicates a higher Q.3. How do I lower the Q factor of a circuit?Sometimes a high Q is undesirable because it causes ringing or oscillation. To lower the Q factor (dampen the circuit), you can add resistance to the circuit. Adding a resistor in series with the inductor increases the denominator in the $Q = \frac{\omega L}{R}$ equation, thereby reducing Q. Alternatively, placing a resistor in parallel with the inductor can also widen the bandwidth and lower the Q.4. Does a higher Q factor always matter?It depends on the application. Yes: In RF tuning, oscillators, and filter circuits, a high Q is essential for sharp selectivity and frequency stability. No (or less so): In some power supply chokes or wideband filtering, a moderate Q is acceptable. In fact, if the Q is too high in a switching power supply filter, it might cause transient ringing spikes that damage components. In these cases, designers might intentionally choose a lower Q or add damping.5. What is the physical meaning of Q factor?In physics and engineering, the quality factor is a dimensionless parameter that describes how underdamped an oscillator or resonator is. A higher Q indicates a lower rate of energy loss relative to the stored energy of the resonator. In simple terms, a high-Q pendulum would swing for a long time (low friction), while a low-Q pendulum would stop quickly (high friction).

CatalogⅠ IntroductionⅡ What is an infrared sensor?Ⅲ How does the infrared sensor work?Ⅳ The basic law of infrared radiationⅤ The working principle of the infrared sensorⅥ Types of infrared sensors  6.1 Thermal sensor  6.2 Photon sensorⅦ Application and Prospect of the infrared sensorⅧ SummaryⅨ FAQⅠ IntroductionAny object in the universe can produce infrared radiation as long as its temperature exceeds zero. In fact, like visible light, its radiation can be refracted and reflected, which leads to infrared technology. Infrared detector is widely used in military and civil fields because of its unique advantages. In the military, infrared detection is used for guidance, fire control tracking, alert, target detection, weapon thermal sight, ship navigation, etc.; in the civil field, it is widely used in industrial equipment monitoring, safety monitoring, disaster relief, remote sensing, traffic management, medical diagnosis technology, etc.With the development of science and technology, the proportion of automatic control and automatic detection in people's daily life and industrial control is more and more heavy, which makes people's life more and more comfortable and the efficiency of industrial production higher and higher. The sensor is an important component of the automatic control, and an important component of the information acquisition system.  Through the sensor, the feeling or response is measured and converted into a signal suitable for transmission or detection (generally electrical signal), and then the computer or circuit equipment is used to process the signal from the sensor to achieve the function of automatic control. Because the response time of the sensor is generally short, the real-time control of industrial production can be carried out through the computer system. The infrared sensor is a common type of sensor.  Because an infrared sensor is a kind of sensor to detect infrared radiation, and any object in nature will radiate infrared energy as long as its stability is higher than absolute zero, so infrared sensor is called a very practical type of sensor. Many practical sensor modules can be designed by using infrared sensors, such as infrared temperature measurement Instruments, infrared imagers, infrared human detection alarms, automatic door control systems, etc.Ⅱ What is an infrared sensor?Infrared sensor is a sensor that uses the physical properties of infrared to measure. Infrared light, also known as infrared light, has the properties of reflection, refraction, scattering, interference, absorption, etc. It is a kind of invisible light, its spectrum is located outside red in visible light, so it is called infrared. In engineering, the position (band) of infrared rays in the electromagnetic spectrum is divided into four bands: near infrared band, mid infrared band, far infrared  band and extremely far infrared band. Any substance can radiate infrared ray, as long as it has a certain temperature (higher than absolute zero).Ⅲ How does the infrared sensor work?First of all, let's learn about infrared light. Infrared light is a part of the solar spectrum. The biggest characteristic of infrared light is its photothermal effect and radiant heat. It is the largest photothermal effect area in the spectrum. An invisible light, like all electromagnetic waves, having the properties of reflection, refraction, scattering, interference, absorption, etc. The propagation speed of infrared light in a vacuum is 300000 km / s. The transmission of infrared light in the medium will produce attenuation, and the transmission attenuation in the metal is very large, but the infrared radiation can pass through most semiconductors and some plastics, and most liquids absorb the infrared radiation very much.Different gases have different absorption levels, and the atmosphere has different absorption bands for different wavelengths of infrared light. The results show that the infrared light with the wavelength of 1-5 μ m and 8-14 μ m has a relatively large "transparency". That is to say, these wavelengths of infrared light can penetrate the atmosphere well. Any object in nature, as long as its temperature is above absolute zero, can produce infrared radiation. The photothermal effect of infrared light is different for different objects, and the intensity of heat energy is also different.  For example, blackbody (an object that can fully absorb the infrared radiation projected on its surface), mirror body(an object that can fully reflect the infrared radiation), transparent body(an object that can fully penetrate the infrared radiation) and gray body (an object that can partially reflect or absorb the infrared radiation) will produce different photothermal effects. Strictly speaking, there are no blackbody, mirror body and transparent body in nature, and most of the objects belong to gray body. These characteristics are the important theoretical basis for the application of infrared radiation technology in military and scientific research projects such as satellite remote sensing and infrared tracking. The physical essence of infrared radiation is thermal radiation. The higher the temperature of an object, the more infrared it radiates, the stronger the energy of the infrared radiation. It is found that the thermal effect of various monochromatic light in the solar spectrum increases gradually from violet light to red light, and the largest thermal effect occurs in the frequency range of infrared radiation, so people call infrared radiation as thermal radiation or thermal ray.Ⅳ The basic law of infrared radiation① Kirchhoff's Law: at a certain temperature, the ratio of the radiation flux W per unit area of the ground object to the absorption rate is a constant for any object, and is equal to the radiation flux w of a blackbody of the same area at that temperature. At a given temperature, the emissivity of the object = the absorptivity (the same band); the higher the absorptivity, the higher the emissivity. The thermal radiation intensity of the ground object is directly proportional to the fourth power of the temperature, so the small temperature difference of the ground object will cause the obvious change of the infrared radiation energy. This feature constitutes the theoretical basis of infrared remote sensing.② Boltzmann's Law: that is, the total radiation flux of blackbody increases rapidly with the increase of temperature, which is proportional to the fourth power of temperature. Therefore, a small change in temperature will cause a great change in radiation flux density. It is the theoretical basis of measuring temperature with an infrared device. ③ Wien displacement law: with the increase of temperature, the peak wavelength corresponding to the maximum radiation value moves to the short wave direction.Ⅴ The working principle of the infrared sensorThe working principle of the infrared sensor is not complicated. The entities of each part of a typical sensor system are as follows:• Target to be tested: the infrared system can be set according to the infrared radiation characteristics of the target to be tested.• Atmospheric attenuation: when the infrared radiation of the target to be measured passes through the earth's atmosphere, the infrared radiation from the infrared source will be attenuated due to the scattering and absorption of gas molecules, various gases and various colloidal particles.• Optical receiver: it receives part of the infrared radiation of the target and transmits it to the infrared sensor. Equivalent to radar antenna, usually objective lens.• Radiation modulator: it can modulate the changed radiation light from the target to be tested, provide the target orientation information, and filter out large-area interference signals. Also known as modulation disk and chopper, it has a variety of structures.• Infrared detector: This is the core of the infrared system. It is a sensor that uses the physical effect of the interaction between infrared radiation and matter to detect infrared radiation. In most cases, it uses the electrical effect of the interaction. These detectors can be divided into two types: photon detector and heat-sensitive detector.• Detector Cooler: because some detectors must work at low temperatures, the corresponding system must have refrigeration equipment. After refrigeration, the equipment can shorten the response time and improve the detection sensitivity.• Signal processing system: amplify and filter the detected signals, and extract information from these signals. Then, this kind of information is transformed into the required format, and finally transmitted to the control equipment or display.• Display device: This is the terminal device of infrared device. Commonly used displays include oscilloscopes, picture tubes, infrared sensitive materials, indicating instruments and recorders.According to the above process, the infrared system can complete the corresponding physical quantity measurement. The core of infrared system is infrared detector. According to the different detection mechanism, it can be divided into two categories: thermal detector and photon detector. The thermal detector absorbs all the radiant energy of all kinds of incident wavelengths. It is an infrared sensor with no choice for infrared light wave. The common photon effects of photon detectors are external photoelectric effect, internal photoelectric effect (photovoltaic effect, photoconductive effect) and photoelectromagnetic effect. The thermal detector uses the radiation heat effect to make the temperature rise after the detector receives the radiation energy, and then the temperature-dependent performance of the detector changes.  Radiation can be detected by detecting a change in one of the properties. In most cases, radiation is detected by thermoelectric changes. When the element receives radiation and causes the physical change of non electric quantity, the corresponding electric quantity change can be measured after appropriate transformation. The response time of thermal detector to infrared radiation is much longer than that of photodetector. The response time of the former is generally more than MS, while that of the latter is only ns. Thermal detectors do not need to be cooled, most photon detectors need to be cooled.Ⅵ Types of infrared sensorsCommon infrared sensors can be divided into thermal sensors and photon sensors.6.1 Thermal sensorThe thermal sensor uses the incident infrared radiation to change the temperature of the sensor, and then make the relevant physical parameters change accordingly. The infrared radiation absorbed by the infrared sensor is determined by measuring the changes of the relevant physical parameters. The main advantage of the thermal detector is that it has a wide band, can work at room temperature and is easy to use. However, the thermal sensor has a long response time and low sensitivity, which is generally used in low frequency modulation.The main types of thermal sensors are thermal sensor type, thermocouple type, gaolai pneumatic type and heat release electric type. ① Thermistor sensorThe thermistor is made of manganese, nickel and cobalt oxides. The thermistor is usually made into thin sheet. When the infrared radiation irradiates the thermistor, its temperature increases and the resistance decreases. By measuring the change of the thermistor value, we can know the intensity of the incident infrared radiation, thus we can judge the temperature of the object generating the infrared radiation.② Thermocouple sensorThermocouples are made of two materials with a great difference in thermal power. When infrared radiation reaches the contact of the closed circuit composed of these two metal materials, the contact temperature increases. The other contact which is not irradiated by infrared radiation is at a lower temperature, at this time, the temperature difference current will be generated in the closed circuit. At the same time, thermoelectric potential is generated in the loop, and the magnitude of thermoelectric potential reflects the strength of infrared radiation absorbed by the contact. The infrared sensor made of thermoelectric potential is called thermocouple infrared sensor. Because of its large time constant, long corresponding time and poor dynamic characteristics, the modulation frequency should be limited below 10Hz.③ Lai pneumatic sensorAfter absorbing the infrared radiation, the temperature and volume of the gas are increased to reflect the intensity of the infrared radiation. It has an air chamber connected to a flexible sheet by a small pipe.  One side of the back pipe of the sheet is a reflector. The front of the gas chamber is attached with an absorption mode, which is a thin film with low heat capacity. The infrared radiation is incident on the absorption mode through the window, and the absorption mode transmits the absorbed heat energy to the gas, which makes the gas temperature and pressure increase, so that the flexible mirror moves.  On the other side of the chamber, a beam of visible light is focused on the flexible mirror through the grating light bar, and the grating image reflected by the flexible mirror is projected onto the photoelectric cell through the grating light bar. When the flexible mirror moves due to the change of pressure, the relative displacement between the grating image and the grating light bar will change the amount of light falling on the photocell, and the output signal of the photocell will also change, which reflects the intensity of the in-out infrared radiation.  This sensor is characterized by high sensitivity and stable performance. But the response time is long, the structure is complex and the intensity is poor, so it is only suitable for laboratory use. ④ Pyroelectric sensorPyroelectric sensor is a kind of thermal crystal or ferroelectric with polarization phenomenon. The polarization intensity (charge per unit area) of ferroelectrics is related to temperature. When infrared radiation irradiates the surface of the polarized ferroelectric sheet, the temperature of the sheet increases, the polarization intensity decreases, and the surface charge decreases, which is equivalent to releasing part of the charge, so it is called pyroelectric sensor.  If the load resistor is connected to a ferroelectric sheet, an electrical signal output is generated on the load resistor. The size of the output signal depends on the speed of the temperature change of the chip, which reflects the intensity of the incident infrared radiation. It can be seen that the voltage response rate of the pyroelectric infrared sensor is directly proportional to the change rate of incident radiation. When the constant infrared radiation irradiates on the pyroelectric sensor, the sensor has no electrical signal output.  Only when the temperature of ferroelectrics is in the process of change can the electrical signal be output. Therefore, it is necessary to modulate the infrared radiation (or chopping light) so that the constant radiation becomes the alternating radiation, which constantly causes the temperature change of the sensor, so as to generate pyroelectric and output the alternating signal.6.2 Photon sensorThe photon sensor uses some semiconductor materials to produce photon effect under the illumination of incident light, which changes the electrical properties of materials. By measuring the change of electrical properties, we can know the intensity of infrared radiation. The infrared sensors made by photon effect are called photon sensors. The main characteristics of photon sensor are high sensitivity, fast response speed and high response frequency, but generally it must work at low temperature and the detection band is narrow. According to the working principle of photon sensor, it can be divided into internal photoelectric sensor and external photoelectric sensor. The latter is divided into photoconductive sensor, photovoltaic sensor and magnetoelectric sensor. ① External photoelectric sensorWhen the light radiates on the surface of some materials, if the photon energy of the incident light is large enough, the electrons of the materials can escape from the surface. This phenomenon is called external photoelectric effect or photoelectron emission effect. Photodiode, photomultiplier tube and so on belong to this type of electronic sensor. Its response speed is relatively fast, generally only a few nanoseconds. However, electron escape requires a large amount of photon energy, which is only suitable for near-infrared radiation or visible light. ② Photoconductive sensorWhen infrared radiation irradiates on the surface of some semiconductor materials, some electrons and holes in the semiconductor materials can change from the original non-conductive bound state to the conductive free state, which increases the conductivity of the semiconductor. This phenomenon is called the photoconductivity phenomenon. The sensors made of photoconductive phenomena are called photoconductive sensors.  For example, lead sulfide, lead selenide, indium antimonide, mercury telluride and other materials can be used to make photoconductive sensors. When using photoconductive sensor, we need to cool and add a certain bias voltage, otherwise, the response rate will be reduced, the noise will be large, the response band will be narrow, and the infrared sensor will be damaged.③ Photovoltaic sensorWhen the infrared radiation irradiates on the PN junction of some semiconductor materials, the free electrons move to the N-region under the action of the electric field in the junction. If the PN junction is open, an additional potential will be generated at both ends of the PN junction, which is called the photogenerated electromotive force.  The sensors or PN junction sensors based on this effect are usually made of materials such as indium arsenide, indium antimonide, mercury telluride, lead-tin telluride, etc. ④ Magnetoelectric sensorWhen the infrared radiation irradiates on the surface of some semiconductor materials, some electrons and holes in the semiconductor materials will diffuse to the interior. If the diffusion is affected by a strong magnetic field, the electrons and holes will each deviate to one side, resulting in an open circuit voltage. This phenomenon is called the optical magnetoelectric effect. The infrared sensor made of this effect is called magnetoelectric sensor. The response band is about 7 μ m, the time constant is small, the response speed is fast, there is no bias, the internal resistance is very low, the noise is small, and it has good stability and reliability. However, its sensitivity is low and it is difficult to make low noise preamplifier, which affects its use.Ⅶ Application and Prospect of the infrared sensor (1) The application of infrared sensor is mainly reflected in the following aspects:    1. Infrared radiometer: used for radiation and spectral radiation measurement.    2. Search and tracking system: used to search and track the infrared target, determine its spatial position and track its motion.    3. Thermal imaging system: it can form the infrared radiation distribution image of the whole target.    4. Infrared ranging system: to measure the distance between objects. (it uses the non-proliferation principle of infrared propagation, because the refractive index of infrared is very small when it passes through other substances, so infrared will be considered in long-distance distance distance rangefinders.)    5. Communication system: infrared communication as a way of wireless communication.    6. Hybrid system: refers to two or more combinations of the above systems.Infrared sensor applications can be used for non-contact temperature measurement, gas composition analysis, nondestructive testing, thermal image detection, infrared remote sensing and military target reconnaissance, search, tracking and communication. With the development of modern science and technology, the application prospect of infrared sensor will be more broad. In the future, the performance and sensitivity of infrared sensor will be improved greatly.  (2) Development trend    1. Intellectualization: at present, the infrared sensor is mainly used in combination with peripheral equipment. The built-in microprocessor of the intelligent sensor can realize the two-way communication between the sensor and the control unit. It has the advantages of miniaturization, digital communication, simple maintenance, etc., and it can work independently as a module.     2. Miniaturization: an inevitable trend of sensor miniaturization. Now in application, because of the volume problem of infrared sensor, its use degree is far worse than that of thermoelectric corner. Therefore, whether the infrared sensor is miniaturized and portable or not can't be ignored.     3. High sensitivity and high performance: in medicine, the infrared sensor has been widely used for the measurement of human body temperature, but it can not replace the existing temperature measurement method due to its low accuracy. Therefore, the high sensitivity and high performance of infrared sensor is the inevitable trend of its future development.Ⅷ SummaryAlthough there are many deficiencies in the current infrared sensor, the infrared sensor has played a huge role in modern production practice. With the improvement of detection equipment and other parts of the technology, the infrared sensor can have more performance and better sensitivity and will have a broader application range. Ⅸ FAQ1. What is the working principle of the IR sensor?Active infrared sensors both emit and detect infrared radiation. Active IR sensors have two parts: a light-emitting diode (LED) and a receiver. When an object comes close to the sensor, the infrared light from the LED reflects off of the object and is detected by the receiver. 2. Why is an infrared sensor important?An infrared sensor is an electronic instrument that is used to sense certain characteristics of its surroundings. It does this by either emitting or detecting infrared radiation. Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion. 3. What is an IR sensor for kids?Light waves longer than red light waves are called infrared light (IR). We cannot see either UV and IR light without special equipment or photography. In the case of infrared sensors, an infrared light source, which is typically an IR LED, is used to transmit light to a receiving infrared sensor. 4. Can IR sensors detect humans?The Passive Infrared (PIR) sensor is used to detect the presence of humans. But this detects the human only if they are in motion. Every human radiates the infrared energy of a specific wavelength range. The absorbed incident radiation changes the temperature of a material. 5. Where are IR sensors used?A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors. PIR sensors are commonly used in security alarms and automatic lighting applications. 6. How do you bypass an infrared sensor?Most motion detectors, even newer ones, use infrared to detect significant changes in the surrounding room's temperature, Porter said. Normally, walking around in a room would set off these sensors, but using something as simple as a piece of styrofoam to shield your body can trick them, he said. 7. What is the difference between an IR sensor and an ultrasonic sensor?The biggest difference between IR sensors vs. ultrasonic sensors is the way in which the sensor works. Ultrasonic sensors use sound waves (echolocation) to measure how far away you are from an object. On the other hand, IR sensors use Infrared light to determine whether or not an object is present. 8. What is the range of the IR sensor?An infrared sensor (IR sensor) is a radiation-sensitive optoelectronic component with spectral sensitivity in the infrared wavelength range 780 nm ...50 µm. IR sensors are now widely used in motion detectors, which are used in building services to switch on lamps or in alarm systems to detect unwelcome guests. 9. Can an IR sensor detect temperature?Infrared temperature sensors sense electromagnetic waves in the 700 nm to 14,000 nm range. ... Because the emitted infrared energy of any object is proportional to its temperature, the electrical signal provides an accurate reading of the temperature of the object that it is pointed at. 10. How do IR sensors detect obstacles?An infrared sensor emits and/or detects infrared radiation to sense its surroundings. ... The basic concept of an Infrared Sensor which is used as an Obstacle detector is to transmit an infrared signal, this infrared signal bounces from the surface of an object and the signal are received at the infrared receiver.