The Kynix Blog

IntroductionCapacitors are components that store electricity and electrical energy (potential energy) and play an important role in circuits such as tuning, bypassing coupling, and filtering. Capacitors are connected in parallel to increase capacity, and capacitors are connected in series to decrease capacity. When the capacitor is connected in series in the circuit, it can prevent the sudden change of voltage and absorb the overvoltage in the peak state. The series resistance plays a damping role, and the resistance consumes the energy of the overvoltage, thereby suppressing the oscillation of the circuit. When the capacitor is connected in parallel, the parallel resistor can absorb the electric energy of the capacitor, prevent the discharge current of the capacitor from being too large, and avoid damaging the devices (such as thyristors) connected in parallel with it. This is a very comprehensive article including the calculation formulas, circuits, and related common problems of series capacitors and parallel capacitors.Capacitors in Series & Parallel - Electronics BasicsCatalogIntroductionCatalogI What are the Capacitors in Series and Parallel?II Calculation Methods of Capacitance of a Series/Parallel Network  2.1 The Series and Parallel Combination  2.2 Voltage Division  2.3 How to Divide the Voltage When Capacitors are Connected in Series?  2.4 What is the Voltage Division Formula When Connecting 2 Capacitors in Series?III The Equivalent Method of Series or Parallel Connection of Capacitors with Different Rated Voltages and CapacitiesIV Comparison Table of Capacitors in Series and Parallel  4.1 Calculation Comparison of Capacitors in Series and Parallel  4.2 Correspondence Between Magnetic Circuit and Electric Circuit  4.3 Basic Physical Quantities of Magnetic Field and Magnetic CircuitV Frequently Asked Questions about Capacitors in Series and ParallelVI Electrolytic Capacitors in Series  6.1 Function and Purpose of 2 Electrolytic Capacitors in Anti-phase Series  6.2 Is the Electrolytic Capacitor in Series a Non-polarised Capacitor?VII QuizVIII FAQI What are the Capacitors in Series and Parallel?1.1 Parallel Connection of CapacitorsWe can describe the capacitors in parallel as a "water tank", but the water tank stores water, and the capacitor stores electric charges. If multiple capacitors are connected in parallel, they can naturally store more charge.(1) The equivalent capacitance after parallel connection is equal to the sum of the capacitance of each capacitance;(2) The voltage at both ends of each capacitor after parallel connection is equal;The withstand voltage after parallel connection is equal to the smallest capacitor voltage, and the equivalent capacitance is C1+C2, as shown in the figure below.Figure1. Parallel Connection of Capacitors1.2 Series Connection of Capacitors(1) The equivalent capacitance capacity after series connection is equal to the sum of the reciprocal of each capacitance;(2) The capacitance of each capacitor after series connection is equal;(3) The withstand voltage after series connection is equal to the sum of each capacitor voltage.After the capacitor is connected in series, it is equivalent to increase the distance between the two poles. The more the number in series, the smaller the capacitance, but the higher the withstand voltage. In actual circuit design, we generally rarely use capacitors in series, but capacitors in parallel are often used. Sometimes the capacity of a single capacitor is not enough, and one more is added.Figure2. Series Connection of CapacitorsII Calculation Methods of Capacitance of a Series/Parallel Network2.1 The Series and Parallel Combination(1) How to calculate the series capacitance of a capacitor?Suppose there are n capacitors connected in series. The series combination of these n capacitors is connected across a voltage source of V volts. Let us consider that the voltages across capacitors 1, 2, 3...n are V 1, V 2, V 3... Vn, respectively. The capacitances of capacitors 1, 2, 3 ... n are C 1, V 2, V 3 ... C n farad. Since all capacitors are connected in series, each of them will get the same charge, ie it is Q Coulomb. Now we know that the charge at both ends of the capacitor is only the product of the potential difference between the two ends of the capacitor and its capacitance value.Since the series combination of these capacitors is connected across the source of the voltage V volts, replacing the series combination n of multiple capacitors.If we consider a single equivalent capacitor of C,Now we get from equations 1 and 2,Therefore, when multiple capacitors are connected in series, the reciprocal of the equivalent capacitance of the system is given by the arithmetic sum of the reciprocal of their respective capacitances. (2) How to calculate the capacitance in parallel circuits?Suppose there are n capacitors connected in parallel. The parallel combination of these n capacitors is connected across the V volt voltage source. Since the capacitors are connected in parallel to the same voltage source, the charge of each capacitor is different and depends on their respective capacitance values. Let us consider that the charges of capacitors 1, 2, 3...n are Q 1, Q 2, Q 3,..., Q n coulombs, respectively. The capacitances of capacitors 1, 2, 3,..., n are C_1, C_2, C_3,... C_n coulombs respectively. It is now known that a charging capacitor is just the product of the voltage across the capacitor and its capacitance value. therefore,Now instead of connecting multiple capacitors in parallel, if we connect a single equivalent capacitor with capacitance C across the voltage source, then the total charge at both ends of the equivalent capacitor,Since all capacitors are connected in parallelWe can get from equations 1 and 2,Therefore, when multiple capacitors are connected in parallel, the capacitance of the system is given by the arithmetic sum of their respective capacitances.Figure3. (a) Three capacitors are connected in parallel. Each capacitor is connected directly to the battery.              (b) The charge on the equivalent capacitor is the sum of the charges on the individual capacitors. (3) Other related calculation formulasWhen the capacitor is connected in parallel, the area of the electrode is increased, and the capacitance is increased. The total capacity when connected in parallel is the sum of each capacity. When the capacitors are connected in series, the resistance value of the capacitor should be smaller than the insulation resistance of the capacitor in parallel to make the voltage distribution on each capacitor even, so as not to damage the capacitor due to uneven voltage distribution. The series and parallel calculations of capacitors are just the opposite of the series and parallel calculations of resistors.Voltage is the voltage during charging. The relationship between capacity and current, voltage is similar to power and is related to load.When voltage and capacity are quantitative, the smaller the load resistance, the larger the current and the shorter the time.When the voltage and load are quantitative, the larger the capacity, the longer the current and the longer the time.But in the actual discharge circuit, the general load is unchanged, the voltage of the capacitor is gradually reduced, and the current is gradually reduced. (1) Electric capacity (uf) = current (mA)/15Current limiting resistance (Ω)=310/maximum allowable surge currentDischarge resistance (KΩ)=500/capacitance (uf) (2) Calculation method C=15×IC is the capacitance of the capacitor, the unit is microfarad; the i device is the working current, the unit is ampere.For example, if the resistance of a bulb is 0.6 amps, the capacitance should be 15×0.6=9 microfarads, and a 9 microfarad capacitor in series is sufficient. (3) Empirical formula, 1uF output 50mA (if it is linear, a 10000F super capacitor can reach a surge current of 500 megaamps) (4) The calculation of the half-wave rectification method should provide about 30mA current per uF capacitance, which is a reference on the 50Hz220V line in China.The current is doubled in full-wave rectification, that is, 60mA current can be provided per uF.Formula: R*C≥(3～5)*T/2, you need to know the frequency of the lowest signal in the ripple component (that is, the maximum T), and then determine the value of C. ● Capacitor capacityCapacitor capacity indicates the size of electric energy that can be stored. The obstructive effect of capacitors on AC signals is called capacitive reactance. The capacitive reactance is related to the frequency and capacitance of the AC signal. The capacitive reactance XC=1/2πf c (f represents the frequency of the AC signal, and C represents the capacitance of the capacitor). ● The capacity unit and withstand voltage of the capacitor.The basic unit of capacitance is F (farad), and other units include: millifarad (mF), microfarad (uF), nanofarad (nF), picofarad (pF). Since the capacity of the unit F is too large, we generally see units of μF, nF, and pF. Conversion relationship: 1F=1000000μF, 1μF=1000nF=1000000pF. Each capacitor has its withstand voltage value, denoted by V. Generally, the nominal withstand voltage of the electrodeless capacitor is relatively high: 63V, 100V, 160V, 250V, 400V, 600V, 1000V, etc. The withstand voltage of polar capacitors is relatively low. Generally, the nominal withstand voltage values ​​are: 4V, 6.3V, 10V, 16V, 25V, 35V, 50V, 63V, 80V, 100V, 220V, 400V, etc. Power capacitor calculation: such as a three-phase capacitor bank with a nominal voltage of 690v and a capacity of 15kvar. Used in 600v circuit, delta connection, the actual effective capacity is: s=15kvar*600*600/(690*690)=11.34kvar. That is: the capacity and voltage are proportional to the square.2.2 Voltage DivisionDue to the large capacity of large capacitors, the volume is generally large, and they are usually made by multi-layer winding, which leads to a relatively large distributed inductance of large capacitors (also called equivalent series inductance, or ESL for short). The impedance of the inductor to the high frequency signal is very large, so the high frequency performance of the large capacitor is not good. Some small-capacity capacitors are just the opposite. Because of their small capacity, the volume can be made small (shortening the lead wire reduces the ESL, because a piece of wire can also be regarded as an inductance), and flat capacitors are often used Structure, such a small capacity capacitor has a small ESL so that it has a good high frequency performance, but due to the small capacity, the impedance to low frequency signals is large. So, if we want to pass the low frequency and high frequency signals well, we use a large capacitor and then a small capacitor.The commonly used small capacitor is 0.1uF CBB capacitor is better (ceramic capacitor is also OK), when the frequency is higher, you can also connect smaller capacitors in parallel, such as a few pF, hundreds of pF. In digital circuits, a 0.1uF capacitor is generally connected to the ground in parallel to the power pin of each chip (this capacitor is called a decoupling capacitor, of course, it can also be understood as a power filter capacitor, the closer the chip is, the better), because The signal in these places is mainly high-frequency signal, and it is enough to use a smaller capacitor to filter. The impedance of an ideal capacitor decreases as the frequency increases (R = 1/jwc), but an ideal capacitor does not exist. Due to the distributed inductance effect of the capacitor pins, the capacitor is no longer a simple capacitor in the high frequency range. , It should be regarded as a series high-frequency equivalent circuit of capacitance and inductance. When the frequency is higher than its resonance frequency, the impedance shows the characteristic of increasing with the increase of frequency, which is the inductance characteristic. At this time, the capacitance is like An inductance. On the contrary, inductors have the same characteristics. Large capacitors in parallel with small capacitors are widely used in power supply filtering. The fundamental reason is the self-resonance characteristics of the capacitor. The combination of large and small capacitors can well suppress low-frequency to high-frequency power interference signals. Small capacitors filter high frequencies (high self-resonant frequency), and large capacitors filter low frequencies (low self-resonant frequency). The two complement each other. ● Series voltage divider ratio: V1 = C2/(C1 + C2)*V...the larger the capacitance, the smaller the voltage divided, which is the same under AC and DC conditions● Parallel shunt ratio: I1 = C1/(C1 + C2)*I...The larger the capacitance, the larger the current that passes. Of course, this is under AC conditions.Explanation: When two or more capacitors are connected in series, it is equivalent to lengthening the insulation distance, because only the two polar plates on the two sides work, and because the capacitance is inversely proportional to the distance, the distance increases and the capacitance decreases; two or two When the above capacitors are connected in parallel, the area equivalent to the plate increases, and because the capacitance is proportional to the area, the area increases and the capacitance increases. ● Capacitors in series: After the capacitors are connected in series, the capacity decreases and the withstand voltage increases. Formula: 1\C1+1\C2=1\C If two 50uf are connected in series, it becomes 25uf.● Withstand voltage = add the withstand voltage values ​​of two capacitors. If two 100V withstand voltages are connected in series, it becomes 200V.● The formula for calculating the capacity of the series circuit of the capacitor C: 1/C=1/C+1/C2+1/C3+.+1/CnC is the total capacitance value of the capacitor series circuit, C1, C2, C3, Cn are the capacitance values of each capacitor in the capacitor parallel circuit, that is, the reciprocal of the total capacitance of the series circuit is equal to the sum of the reciprocal of the capacitance of each capacitor in the series circuit.Figure4. Capacitors in Series and Parallel2.3 How to Divide the Voltage When Capacitors are Connected in Series?For example 4V voltage source, two capacitors of 0.5F and 1F in series. If it is a DC voltage source, according to the characteristics of capacitor series voltage division introduced in middle school physics:(1) The total voltage across the capacitor series circuit is equal to the sum of the divided voltages across the capacitors. That is, U= U1+ U2+ U3+…+Un.(2) When capacitors are connected in series, the voltage distributed on each capacitor is inversely proportional to its capacitance. That is, Un = Q / Cn (because in the capacitor series circuit, the amount of charge carried on each capacitor is equal, so the larger the capacitor, the lower the voltage, and the smaller the capacitor, the higher the voltage. .)Then the voltage source of 4V, the voltage on the two capacitors of 0.5F and 1F are 8/3V and 4/3V respectively 2. If it is an AC voltage source, from the impedance of the capacitor Xc=1/jωC, we can see |Xc| and C In inverse proportion, the same result can be obtained by using |Xc| as a resistor to calculate the voltage divider.2.4 What is the Voltage Division Formula When Connecting 2 Capacitors in Series?This is a theoretical calculation problem. It is necessary to assume that the withstand voltage value of the capacitor has no margin, that is, a capacitor of 200pF is breakdown when it exceeds 500V; a capacitor of 300pF is breakdown when it exceeds 900V.After adding 1000V voltage, the 200pF capacitor will withstand 600V voltage. Regardless of the capacitor's withstand voltage margin, the 200pF capacitor will break down; at this time, 1000V will all be added to the 300pF capacitor, which exceeds its withstand voltage, so it will breakdown. Calculation formula:If there are M capacitors connected in series, the actual voltage value Un of any capacitor Cn is:Un=U*C/Cn Among them: U is the total voltage; C is the total capacity of M capacitors in series.For two capacitors in series, the formula evolves into:Assuming that the total voltage is U, the voltages on C1 and C2 are U1 and U2 respectively, thenU1=C2*U/(C1+C2)U2=C1*U/(C1+C2)III The Equivalent Method of Series or Parallel Connection of Capacitors with Different Rated Voltages and CapacitiesThe equivalent method of using capacitors with the same rated voltage in series or in parallel is relatively simple and commonly used.Several capacitors with different rated voltages and different capacities are connected in series or in parallel, and the equivalent methods are different. Now give examples to illustrate. There are three capacitors C1: 220µF /10V C2: 100µF/25V C3: 10µF/100VCalculate their parallel and series equivalent values ​​respectively. (1) Parallel equivalent method1) Equivalent capacitanceC and = C1 + C2 + C3= 220µF + 100µF + 10µF/= 330µF2) Equivalent withstand voltageU parallel = U1 = 10V (take the minimum withstand voltage value U1) (2) Series equivalent method1) Equivalent capacitance1/C string ==1/C1 + 1/C2 + 1/C3= 1/220 + 1/100 + 1/10= 252/2200C string == 2200/252≈ 8 (µF)2) Equivalent withstand voltage ● Compare the Q value of each capacitorQ1= C1 X U1 Q2=C2 X U2 Q3=C3 X U3= 220 X 10 =100 X 25 =10 X 100=2200 (C) =2500 (C) =1000 (C)Q = Q3 =1000 (C) (take the minimum power value Q3) ● Find the actual allowable withstand voltage value of each capacitorU1 (actual) = Q/C1 U2 (actual) = Q/C2 U3 (actual) = Q/C3= 1000/220 = 1000/100 = 1000/10≈4.5(V) = 10 (V) =100 (V)3) U string = U1 (actual) + U2 (actual) + U3 (actual)≈4.5 + 10 + 100≈114.5(V)Figure5. Equivalent CapacitanceIV Comparison Table of Capacitors in Series and Parallel4.1 Calculation Comparison of Capacitors in Series and Parallel4.2 Correspondence Between Magnetic Circuit and Electric Circuit4.3 Basic Physical Quantities of Magnetic Field and Magnetic CircuitV Frequently Asked Questions about Capacitors in Series and Parallel(1) Do capacitors charge faster in parallel or series?If two capacitors with the same capacity are connected in parallel or in series in the same circuit, the capacitor in series will charge faster, because the capacity of the capacitor is reduced by half after the capacitor is connected in series, and the charging time becomes shorter. The capacity of the capacitor after parallel connection is doubled, and the charging time will be longer for the same charging circuit. (2) The electric charge of each capacitor in the series circuit is equal. Why is the electric charge of each capacitor equal to the electric charge of the equivalent capacitor?Capacitor voltage: U=Q/CQ=I*tSo U=(I*t)/CWhen the capacitors connected in series are connected to the power supply, the capacitors start to charge. The current flowing through each capacitor is the same. As time goes by, the voltage of each capacitor increases. However, due to the different voltage rise rates of C, the sum of the voltage of each capacitor is equal to the power supply. When the voltage is applied, charging stops and the current is zero. Analyze this process: the current flowing through each capacitor during the entire charging process is the same, and the elapsed time is the same, so the current of each capacitor is the same over time, so the amount of charge is the same and equal to the capacity of the capacitor.Figure6. A Charging State of Three Capacitors in Parallel(3) Are the filter capacitors in the power amplifier power supply connected in parallel?The filter capacitor of the power amplifier power supply is set to eliminate some of the AC components contained in the rectification from AC to DC (the purpose is to improve the audio quality), so all capacitors with larger capacity are selected, generally using electrolysis above tens of microfarads Capacitor. The parallel connection of capacitors is the addition of the capacity of each capacitor, usually forming a standard type 1 filter circuit: "capacitor-resistor (or inductance)-capacitor". If the capacitors are connected in series, the capacity will decrease, it will only increase the cost and occupy more space, meaningless. The power supply line filter capacitor of the amplifier circuit of the power amplifier is generally grouped in parallel. Depending on the design of the power supply, the single power supply circuit may also be directly connected in parallel, or divided into two groups. The two groups are separated by power inductors or resistors into two filter circuits to form a pie-type filter circuit; if it is a dual power supply circuit, , It is generally divided into two groups as for the two groups of power lines. The easiest way to increase the filter capacitor of the power amplifier is to see the positive and negative poles and the rated withstand voltage. Connecting them in parallel can improve the stability of the DC voltage and improve the low-frequency characteristics of the amplifier, making the low frequency of the speaker sound more full and round. Capacitors are generally used in parallel, and capacitors of different capacities filter noise at different frequencies. Large-capacity capacitors can only be realized by electrolytic capacitors. Electrolytic capacitors have positive and negative polarity and are very loud when connected reversely.VI Electrolytic Capacitors in Series6.1 Function and Purpose of 2 Electrolytic Capacitors in Anti-phase SeriesIn some circuit designs, it is seen that two electrolytic capacitors are connected in series in the reverse phase. The capacity of the two components should be equal and the withstand voltage is the same. In AC circuits, the leakage current can be reduced. Just use a non-polar capacitor to get a large-capacity non-polar capacitor. . Large-capacity non-polar capacitors are more expensive. The electrolytic capacitor has a large capacity and is cheap, but it has a polarity, and the two are connected in reverse series. It is non-polar. It can only be used in very low voltage applications (up to 1-2V). The voltage is slightly higher. When the capacitor is used in the opposite direction, the leakage will be large. The accumulated effect will cause the electrolytic capacitor to heat up and eventually cause the capacitor to explode. Electrolytic capacitors are used in DC circuits. So its series connection should be the negative pole of the first one and the positive pole of the second (just like dry batteries in series). But in the circuit, there is indeed a case where the negative poles of two electrolytic capacitors are connected to the negative pole (inverted series), and the two positive poles are used. This is because it is used in an AC circuit (in a circuit where DC and AC coexist), There is no guarantee that the potential of one pole is always higher than the other pole), so that when the capacitor is under reverse voltage, serious leakage current will be generated. At this time, non-polar capacitors should be used, but non-polar capacitors are expensive and expensive. The volume is large, so some people use two electrolytic capacitors to "reverse series".  Its working state is that when there is alternating current, one of them is in the reverse state. Due to its serious leakage, the voltage drop across it is very small. Almost all of the voltage falls on the positive capacitor, and when the other half cycle of the alternating current, the state of the two capacitors will be exchanged, so these two capacitors are used as one, and the total capacitance is equal to any one of them. The total withstands voltage value is equal to 2 times of any capacitor.6.2 Is the Electrolytic Capacitor in Series a Non-polarised Capacitor?Of course, two electrolytic capacitors in parallel will not work. If two electrolytic capacitors are connected in series, it will still not work without applying a proper bias voltage. Applying a bias voltage is quite complicated, especially when both ends of the capacitor (two in series) are not grounded (the bias voltage must be floating). Considering the complexity of applying the bias voltage, it is better not to use this method: connect the negative poles of the two capacitors, and connect the two capacitors in parallel with a high-current diode. The positive of the diode is connected to the negative of the capacitor, and the negative is connected to the positive of the capacitor. Parallel connection of course still has polarity. If reverse parallel connection, it is non-polar, but it is non-polar. Reverse series connection is also not advisable. If you do a test, you will find that there must be a capacitor that withstands the backpressure. If the voltage is large, it will blow up. Unless special measures are taken, the voltage is always applied to the capacitor with the positive voltage. on. Two electrolytic capacitors of the same capacity can be connected in series, but a diode must be connected in anti-parallel to prevent the reverse breakdown of the electrolytic capacitor. After adding a diode, it is okay if it is used for filtering, but it is definitely not good for blocking DC. Because the electrolytic capacitor is only charged and not discharged. Two identical electrolytic capacitors connected in reverse series can replace non-polar capacitors with the same capacity. The dielectric loss of the electrolytic capacitor is very large, and it must be connected to the AC circuit after the voltage is greatly reduced. Otherwise, it is either burned or fried.VII Quiz● QuestionA network of five capacitors of C is connected to a 100 V supply, as shown below figure. Determine(a) the equivalent capacitance of the network(b) the charge on each capacitor. ● SolutionIn the given network, the top three Capacitance is in series, So equivalent capacitance of the top part1C1=1C+1C+1CC1=C3Similarly, the lower two Capacitance is in series, So equivalent capacitance of lower part1C2=1C+1CC2=C2 Now both C1 and C2 are in parallel, so equivalent Capacitance of the NetworkCeq=C1+C2=C3+C2=5C3Now Charge on top part will beQ1=C1V=CV3Now Charge on lower part will beQ2=C2V=CV2  VIII FAQ1. How do you solve capacitors in series and parallel?To calculate the total overall capacitance of a number of capacitors connected in this way you add up the individual capacitances using the following formula: CTotal = C1 + C2 + C3 and so on Example: To calculate the total capacitance for these three capacitors in parallel. 2. How do you know if a capacitor is in series or parallel?In your circuit current, all of the current going to one capacitor must also go to the other. Therefore they are in series. Hope this helps. If two (two-terminal) circuit elements are series-connected, they have identical (not just equal) currents through. 3. What is a capacitor in parallel?Capacitors are connected together in parallel when both of their terminals are connected to each terminal of another capacitor. The voltage ( Vc ) connected across all the capacitors that are connected in parallel is the same. 4. Can you put two capacitors in series?If two or more capacitors are connected in series, the overall effect is that of a single (equivalent) capacitor having the sum total of the plate spacings of the individual capacitors. With resistors, series connections result in additive values while parallel connections result in diminished values. 5. How are capacitors connected in series?Here are the rules for calculating capacitances in series: If the capacitors are of equal value, you're in luck. All you must do is divide the value of one of the individual capacitors by the number of capacitors. For example, the total capacitance of two, 100 μF capacitors is 50 μF. 6. Why capacitor is connected in parallel?Capacitors are devices used to store electrical energy in the form of electrical charges. By connecting several capacitors in parallel, the resulting circuit is able to store more energy since the equivalent capacitance is the sum of individual capacitances of all capacitors involved. 7. Do capacitors in series increase voltage?Capacitors connected in series will have lower total capacitance than any single one in the circuit. This series circuit offers a higher total voltage rating. The voltage drop across each capacitor adds up to the total applied voltage. This is why series capacitors are generally avoided in power circuits. 8. Do capacitors in series or parallel store more energy?The energy stored in a capacitor is a function of the voltage across the capacitor. The voltage will be higher when they are in parallel, so the parallel connection stores the most energy. 9. Why voltage is different in a series combination of capacitors?In a series combination, since the charge stored is the same as the same charge flows through all the capacitors, the potential difference across each will be different. 10. When capacitors are wired in parallel what must be the same for the two capacitors?The charge in the two capacitors is different. Capacitors connected in parallel are connected to the same start and end points of the input and output that's why they have the same potential difference.  

 IntroductionPower systems are more complex than we see. In reality, we cannot see components of electricity, but we can inject how it works (or does not work). A current transformer is one of many elements that come together like a puzzle to form electrical power. A CT is made up of a laminated steel core, a secondary winding around the core, and insulating material surrounding the windings in its most basic form.Current transformers can be used in a variety of metering applications and use, including Wattmeters, power factor meters, watt-hour meters, protective relays, and as trip coils in magnetic circuit breakers, or MCBs.  CatalogIntroductionⅠ What is a Current TransformerⅡ Classification and Types of Current TransformerⅢ The function of Current TransformerⅣ Application of  Current TransformerⅤ Current Transformer Ratio and Polarity    5.1 Current Transformer Ratio  5.2 Current Transformer Polarity    5.3 Electrical Drawing Conventions for CT PolarityⅥ  How to Test CT PolarityⅦ  How to Choose The Right Current Transformer7.1 Genres of System7.2 Requirement of PrecisionⅧ Frequently Asked Questions about Current  Transformer  Ⅰ What is a Current Transformer A current transformer is a device that generates an alternating current in its secondary that is proportional to the alternating current in its primary. When a current or voltage is too high to measure directly, this method is applied. The induced secondary current is then appropriate for measuring instruments or processing in electronic equipment that requires isolation between the primary and secondary circuits.Because high-voltage currents are reduced, a standard ammeter can be used to safely monitor the actual electrical current flowing in an AC transmission line.Figure1: current transformers An electrical CT differs from a voltage or power transformer in that its primary winding has only one or a few turns. It also differs from a voltage transformer in that the prime current is not controlled by the secondary load current but rather by an external load. The CT ratio is the number of secondary turns multiplied by the number of primary turns. This ratio is calculated based on the primary conductor passing through the transformer window once. Ⅱ Classification and Types of Current Transformer There are two categories in the current transformer. The first, a measuring current transformer, is applied to conjunct with measuring devices for current magnitude, energy, and power. The other, a protective current transformer, is used in conjunction with protective equipment such as trip coils, relays, and the like.Current transformers are classified into three basic types: wound, toroidal, and bar.  1. Wound Current Transformer–The primary winding of the transformer is physically connected in series with the conductor carrying the measured current flowing in the circuit. The magnitude of the secondary current is determined by the transformer's turns ratio.  2. Toroidal Current Transformer -There is no primary winding in these. Instead, the line carrying the network's current is threaded through a window or hole in the toroidal transformer. Some current transformers have a "split core," allowing them to be opened, installed, and closed without disconnecting the circuit to which they are connected.  3. Bar-type Current Transformer-The primary winding of this type of current transformer is the actual cable or bus-bar of the main circuit, which is equivalent to a single turn. They are fully insulated from the system's high operating voltage and are typically bolted to the current-carrying device. Bar-type Current Transformer.Figure2: the typical current transformer  Ⅲ The function of Current Transformer One of the functions of the current transformer is to be used for measurement, and it is often used for billing or measuring the current of the equipment in operation. When measuring large alternating currents, to facilitate meter measurement and reduce the risk of direct measurement of high-voltage electricity, it is often necessary to use current transformers to convert them into a more uniform current. Thus, current transformers are considered as the role of current conversion and electrical isolation.Another function is protection : It is frequently used in tandem with a relay device. When a short circuit or overload occurs in the line, the current transformer sends a signal to the relay device to cut off the fault circuit, thereby protecting the power supply system's safety. The current transformer used for protection is not the same as the current transformer used for measurement. It can only operate effectively when the current is tens of times greater than the normal current, and it requires reliable insulation as well as a sufficiently great accurate limit. The coefficient has adequate thermal and dynamic stability.  Ⅳ Application of  Current Transformer Current transformers are widely used for measuring current and monitoring power grid operation. Revenue-grade CTs, along with voltage leads, power the electrical utility's watt-hour meter on many larger commercial and industrial supplies.To isolate high-voltage current transformers from the ground, they are mounted on porcelain or polymer insulators. Some CT configurations wrap around the bushing of a high-voltage transformer or circuit breaker, allowing the conductor to be automatically centered inside the CT window.Current transformers can be installed on a power transformer's low or high-voltage leads. A section of a bus bar can sometimes be removed to replace a current transformer.High-voltage current transformers are mounted on porcelain or polymer insulators to isolate them from the ground. Some CT configurations wrap around the bushing of a high-voltage transformer or circuit breaker, allowing the conductor to be centered inside the CT window automatically.  Ⅴ Current Transformer Ratio and Polarity5.1 Current Transformer RatioAt full load, the CT ratio is the ratio of primary current input to secondary current output. A CT with a ratio of 300:5 is rated for 300 primary amps at full load and will generate 5 amps of secondary current when 300 amps pass through the primary.If the primary current changes, so will the secondary current output. For example, if 150 amps flow through a primary rated at 300 amps, the secondary current is 2.5 amps. Figure3: A current transformer's ratio is equivalent to a potential transformer's voltage ratio.  At full load, the CT ratio is the ratio of primary current input to secondary current output. A CT with a ratio of 300:5 is rated for 300 primary amps at full load and will generate 5 amps of secondary current when 300 amps pass through the primary.If the primary current changes, so will the secondary current output. For example, if 150 amps flow through a primary rated at 300 amps, the secondary current is 2.5 amps.   5.2 Current Transformer PolarityThe polarity of a current transformer is determined by the direction in which the coils are wound around the CT's core (clockwise or counterclockwise), as well as the manner in which the secondary leads are brought out of the transformer case.To ensure an appropriate installation, all current transformers are subtractive polarity and will have the following designations: H1 - Primary current, oriented in the direction of the lineH2 - Primary current in the load-facing directionX1 denotes secondary current (multi ratio CTs have additional secondary terminals) Figure4:  Split-Core CT with a 200A rating. Take note of the polarity marking in the center of the core, which indicates the direction of the source. (Split-Core CT with a 200A rating.) Take note of the polarity marking in the center of the core, which indicates the source's direction. (Photo courtesy of Continental Control Systems, LLC.)The H1 primary lead and the X1 secondary lead are on the same side of a subtractive polarity transformer. When the polarity of a CT is indicated by an arrow, it should be installed with the arrow pointing in the direction of the current flow.When installing and connecting current transformers to power metering and protective relays, it is critical to maintain proper polarity.   5.3 Electrical Drawing Conventions for CT PolarityFor current transformers, polarity markings on electrical drawings and diagrams can be made in a variety of ways. Dots, squares, and slashes are the three most common schematic conventions. On electrical drawings, polarity markings represent H1, which should be facing the source.Figure5: Electrical Drawing Conventions for CT Polarity   Ⅵ  How to Test CT PolarityMaterials need:an analog voltmeter9-volt batteryThe factory has occasionally misapplied markings on current transformers. The following test procedure can verify the polarity of a CT in the field with a 9V battery: Step1: Cut the Power SupplyBefore testing, turn off all power and connect an analog voltmeter to the secondary terminal of the CT to be tested. The meter's positive terminal is connected to CT terminal X1, while the negative terminal is connected to X2.  Step2: Connect the 9-volt BatteryConnect the positive end of the 9-volt battery to the H1 side (sometimes marked with a dot) and the negative end to the H2 side with a piece of wire run through the high side of the CT window. It is critical to avoid continuous contact, which will result in a short circuit of the battery.  Step3: Check the PolarityIf the polarity is correct, the momentary contact causes a tiny positive deflection in the analog meter. If the deflection is negative, the current transformer's polarity is reversed. The terminals X1 and X2 have to be switched before the test.Figure6:The factory has occasionally misapplied markings on current transformers. A 9-volt battery can be used to test the polarity of a CT in the field.   Ⅶ  How to Choose The Right Current TransformerWhen selecting a current transformer for any application, there are numerous factors to consider. As this can be confusing, and there is a lot of inaccurate information out there, it can lead to installing the wrong current transformer and having to replace equipment.To avoid this, the first step should be to contact the current transformer manufacturer if you have any questions or concerns about compatibility. Midwest Current Transformer's team is available to answer your questions and ensure that you are using the correct product. Speaking with our team before ordering current transformers ensures that you have the right equipment for the job, avoiding any last-minute decisions and potential confusion. 7.1 Genres of SystemWhen using any genre of the meter or power system, it is critical to use a current transformer that is specifically designed for that system. It is especially important with meters because they are not all uniformly designed. Another way to put it is that the system's metering or protection is matched with the type of current transformer.It is also critical to understand the primary range of the current transformer and ensure that it is compatible with the application. This type of compatibility is provided by the various configurations of the primary and secondary windings.  7.2 Requirement of PrecisionThe degree of accuracy is critical for current transformers used for measurement. Not all current transformers provide high accuracy, and the more specific the requirement, the more important the quality of data measurement provided by the CT.This accuracy rating is classified according to class, with the current having an effect on the accuracy provided by the current transformer. The ability of the current transformer to perform to the required levels is always a factor in making the right choice for protective transformers..The degree of accuracy is critical for current transformers used for measurement. Not all current transformers provide high accuracy, and the more specific the requirement, the more important the quality of data measurement provided by the CT.This accuracy rating is classified according to class, with the current having an effect on the accuracy provided by the current transformer. The ability of the current transformer to perform to the required levels is always a factor in making the right choice for protective transformers. Ⅷ Frequently Asked Questions about Current Transformer 1.What is the use of current transformer?A Current Transformer (CT) is used to measure the current of another circuit. CTs are used worldwide to monitor high-voltage lines across national power grids. A CT is designed to produce an alternating current in its secondary winding that is proportional to the current that it is measuring in its primary. 2.What is the use of CT and PT?CT is used to measure current while PT is used to measure voltage. CT is connected in series while PT is connected in parallel. CT ratio range is from 1 to 5A while the PT range is from 110V. We connect the output parameter from CT to the ampere meter while we connect the PT output to the voltmeter. 3.What do you mean by a current transformer?A current transformer is a device used to produce an alternating current in its secondary, which is proportional to the AC current in its primary. This is primarily used when a current or voltage is too high to measure directly. ... This ratio is based on the primary conductor passing once through the transformer window. 4.How is CT ratio calculated?When analog ammeters are installed, we can easily determine the CT ratio by observing the meter full scale value and then divide that value by 5. Figure 3. Ammeter with a full scale of 150 amps. The meter in Figure 3 has a full scale of 150 amps. 5 Why CT is connected in series?A CT may be considered as a series transformer. The primary current in a C.T is independent of the secondary circuit conditions (burden/load). The primary winding of the CT is connected in series with the line carrying the current to be measured. Hence it carries of the full line current.   

Ⅰ IntroductionThere are 400 types of scent receptors in a typical human nose that allow us to detect about 1 trillion different odors. But many of us also can't define the form or concentration of gas in our atmosphere. There are several kinds of sensors to calculate various parameters and a gas sensor is one that is useful in applications where we have to detect changes in the concentration of harmful gases to keep the device safe and prevent any unwanted threats. To detect gases such as oxygen, carbon dioxide, nitrogen, methane, etc., there are different gas sensors. They can also be widely used in devices that are used in factories and offices to detect the leakage of toxic gases, track air quality, etc. We will learn more about gas sensors, their construction, types, function, and how they can be used to calculate the type and concentration of gas required in our atmosphere in this article. There are several kinds of gas sensors, but gas sensors of the MQ type are frequently used and widely popular, so this article will concentrate more on these types of sensors.CatalogⅠ IntroductionⅡ Introduction of Gas SensorⅢ Different Types of Gas sensorsⅣ Construction of Gas SensorⅤ Working of Gas SensorⅥ Working Principle of Gas SensorⅦ How can a gas sensor be used?Ⅷ Gas Sensors List and What Gases They SenseⅨ Gas Sensors ApplicationsⅩ FAQⅡ Introduction of Gas SensorA gas sensor is a device that senses the atmosphere's presence or concentration of gases. The sensor creates a corresponding potential difference depending on the concentration of the gas by adjusting the resistance of the material within the sensor, which can be determined as the output voltage. The type and concentration of the gas can be calculated based on this voltage value.The type of gas that can be detected by the sensor depends on the sensing material within the sensor. As shown above, these sensors are usually available as modules with comparators. A specific threshold value of the concentration of gas may be set for these comparators. The automated pin goes up when the concentration of the gas reaches this threshold. It is possible to use the analog pin to measure the gas concentration.Ⅲ Different Types of Gas sensorsBased on the type of sensing element it is designed with, gas sensors are usually categorized into different categories. Below is the classification based on the sensing aspect of the different types of gas sensors that are commonly used in different applications:• Metal Oxide Based Gas Sensor.• Optical Gas Sensor.• Electrochemical Gas Sensor.• Capacitance-based Gas Sensor.• Calorimetric Gas Sensor.• Acoustic Based Gas Sensor.Ⅳ Construction of Gas SensorThe Metal Oxide Semiconductor Based Gas Sensor is the most widely used gas sensor of all the above types. A sensing component containing the following elements will consist of all gas sensors.• Gas Sensing Layer• Heater Coil• Electrode Line• Tubular Ceramic• ElectrodeThe picture below shows the components of a metal oxide gas sensor.The goal of each of these elements is as shown below.:• Gas sensing layer: It is the main component of the sensor that can be used to detect changes in gas concentration and produce electrical resistance changes. The gas sensing layer is essentially a chemical resistor that adjusts its resistance value depending on the environment's real gas concentration. The sensing factor consists of a Tin Dioxide (SnO2) here, which generally has excess electrons (donor element). Therefore, the resistance of the element changes and the current flown through it varies as toxic gases are detected, which reflects the shift in gas concentration. • Heater coil: The purpose of the heater coil is to burn the sensing component to increase the sensitivity and efficiency of the sensing component. It is made of nickel-chromium with a high melting point that allows it to remain heated without melting. • Electrode line: Since a very small current is generated by the sensing element when the gas is detected, preserving the efficiency of carrying those small currents is more critical. So Platinum wires come into play where they help to efficiently transfer the electrons. • Electrode: It is a junction where the sensing layer output is attached to the line of the electrode. So that the output current may flow to the terminal that is needed. Gold (Au-Aurum), which is a very good conductor, is an electrode here. • Tubular ceramic: There is a tubular ceramic made from aluminum oxide between the heater coil and the gas sensing layer (Al2O3). As it has a high melting point, it helps to preserve the sensing layer's burn-in (preheating), which provides the sensing layer with high sensitivity to obtain an effective output current. • Mesh over the sensing element: A metal mesh is used over it to cover the sensing elements and the setup, which is also used to prevent/hold dust particles from entering the mesh and to prevent damage from corrosive particles to the gas sensing layer.Ⅴ Working of Gas SensorA gas sensor's ability to detect gases relies on the chemiresistor to conduct current. Tin Dioxide (SnO2), which is an n-type semiconductor with free electrons, is the most widely used chemical resistor (also called a donor). The atmosphere usually contains more oxygen than combustible gases. The particles of oxygen attract the free electrons present in SnO2, bringing them to the surface of SnO2.  As there are no free electrons available, there will be a zero output current. The gif below shows the oxygen molecules (blue color) within the SnO2 attracting the free electrons (black color) and preventing them from having free electrons to perform the current.Ⅵ Working Principle of Gas SensorThis decreasing gas (orange color) interacts with the adsorbed oxygen particles when the sensor is put in the atmosphere of toxic or combustible gases and breaks the chemical bond between oxygen and free electrons, thereby releasing free electrons. As the free electrons return to their original location they will now conduct current, this conduction would be proportional to the number of free electrons available in SnO2 if more free electrons are available for the gas to be highly toxic.Ⅶ How can a gas sensor be used?There are 6 terminals in a simple gas sensor in which 4 terminals (A, A, B, B) serve as input or output and the remaining 2 terminals (H, H) are used to heat the coil. Of these 4 terminals, 2 terminals from each side can be used as either input or output (as seen in the circuit diagram, these terminals are reversible) and vice versa.MQ2 Gas sensor PinoutThese sensors are usually available as modules (shown on the right), consisting of a gas sensor and an IC comparator. Now let's see the gas sensor module pin definition that we normally use with an Arduino. The module for the gas sensor consists of 4 terminals.• Vcc – Power supply• GND – Power supply• Digital output – This pin produces an output that is either logically high or logically low (0 or 1), indicating that it shows any harmful or combustible gases near the sensor.• Analog output – This pin provides a continuous voltage output that varies depending on the gas concentration added to the gas sensor.The output of a gas sensor alone would be very small (in mV) as discussed earlier, so an external circuit has to be used to get a digital high low output from the sensor. A comparator (LM393), adjustable potentiometer, some resistors and capacitors are used for this purpose. The goal of LM393 is to get the sensor output, compare it to a reference voltage, and show whether or not the output is logically high. Whereas the potentiometer is intended to set the gas threshold value needed above which the digital output pin should go high. A simple circuit diagram of a gas sensor in a gas sensor module is shown in the diagram below.The input and output terminals here are A and B (these are reversible - meaning either of the paired terminals can be used as input or output) and H is the terminal for the heater coil. The purpose of the variable resistor is to change the voltage of the output and maintain high sensitivity. If the heater coil has no input voltage, so the output current would be much smaller (which is negligible or approximately 0). The sensing layer wakes up when an appropriate voltage is applied to the input terminal and heater coil and is ready to detect any combustible gases near it. Let's first presume that there is no poisonous gas near the sensor, so the layer's resistance does not shift and the output current and voltage are also unchanged and insignificant (approximately 0). Now, let's say that poisonous gas is nearby. Since the heater coil is pre-heated, any combustible gases can now be easily detected. The resistance of the material varies as the sensing layer interacts with the gases, and the current flowing through the circuit often varies. This variation shift can then be observed in the load resistance (RL). The load resistance (RL) value can be anywhere from 10K to 47K. It is possible to pick the exact value of the load resistance by calibrating it with the known gas concentration. The circuit has lower sensitivity if the low load resistance is chosen, and if the high load resistance is selected, then the circuit has high sensitivity.Ⅷ Gas Sensors List and What Gases They SenseSensor NameGas to measureMQ-2Methane, Butane, LPG, SmokeMQ-3Alcohol, Ethanol, SmokeMQ-4Methane, CNG GasMQ-5Natural gas, LPGMQ-6LPG, butaneMQ-7Carbon MonoxideMQ-8Hydrogen GasMQ-9Carbon Monoxide, flammable gassesMQ131 Ozone............Ⅸ Gas Sensors Applications• It is used to track the concentration of toxic gases in industries.• Used in homes to recognize activities in an emergency.• The concentration of the gases that are emitted is tracked at oil rig locations.• Used at hotels to discourage smoking by clients.• Used in workplace air quality inspections.• It is used to track CO2 levels in air conditioners.• Used in fire detection.• Used for gas concentration regulation in mines.• The analyzer of breath.Ⅹ FAQ1. What is a gas sensor?As the name suggests, it senses gas. It's a component used to detect fluctuations in the gaseous state. There are so many gas sensors based on the element they sense, some are given below:• Carbon Dioxide Sensor: Used for detection of pollution caused by vehicles emitting CO2.• Alcohol Sensor: I know alcohol is not a gas but it senses the smell of it. Traffic police use devices based on this sensor.• LPG Sensor: It is used for avoiding the destruction caused by leaked LPG cylinders. 2. What are gas sensor arrays?A gas sensor that is commonly available in the market is an MQ-x series sensor - MQ2, MQ3, MQ6, etc. The module for this series sensor gives a digital output but can even be modified to have an analog output. MQ2 sensor can detect gasses like propane, butane, LPG, smoke and alcohol. An array of gas sensors would mean that all the sensors of this category are interfaced to the same controller and are laid at different locations to monitor the aspect. 3. How does a gas sensor work?Gas detectors use a sensor to measure the concentration of particular gases in the atmosphere. The sensor serves as a reference point and scale, producing a measurable electric current when a chemical reaction caused by a specific gas occurs. 4. How do MQ5 gas sensors work?In any sensor, a physical change contributes to a chemical change that generates an electrical impulse which then drives a circuit.Similarly here, the MQ5 gas sensor which is made of SnO2 is less conductive normally. In LPG or any combustible gas environment like propane-butane etc., it becomes more conductive.A circuit similar to the Wheatstone bridge will be available inside the sensor with one of its resistance made of SnO2. Assume a bridge balanced condition. When the conductivity changes bridge becomes unbalanced. Hence current flows through the center galvanometer showing deflection.  5. What is the difference between a gas analyzer and a gas detector?A gas detector has simple structures, consisting only of the sensor and sensor conversion circuit. However, a gas analyzer not only has sensors inside but also has a complete set of pneumatic systems, which introduces the sample gas into the instrument firstly and then discharges or retrieves the gas. 6. What is the use of a gas sensor?Gas sensors (also known as gas detectors) are electronic devices that detect and identify different types of gasses. They are commonly used to detect toxic or explosive gasses and measure gas concentration. 7. How long do gas detectors last?The typical life span of an electrochemical sensor is usually between 2-3 years. Whereas a more exotic gas sensor may only last 12-18 months. I would advise anyone who uses a gas detector to get the instrument serviced every 6 months as this will ensure that your instrument will be working perfectly. 8. What is gas sensor sensitivity?Usually, sensitivity (S) can be defined as Ra/Rg for reducing gases or Rg/Ra for oxidizing gases, where Ra stands for the resistance of gas sensors in the reference gas (usually the air) and Rg stands for the resistance in the reference gas containing target gases. 9. What is the most important sensor in a gas monitor?The most important technical aspect of all gas detectors is the heart of the instrument - the sensor. All the bells and whistles that can be crammed into one instrument can't take away from the simple fact that sensors must technically process incoming gases and vapors and provide an accurate response. 10. What is a gas sensor made of?Highly sensitive and selective sensors are needed for the detection and prevention of hazardous gas leaks from industries. Generally used gas-sensing materials comprise vapor-sensitive polymers, semiconductor metal oxides, and other porous materials such as silicon.

CatalogⅠ IntroductionⅡ What is USB-C?Ⅲ What is HDMI?Ⅳ USB-C to HDMI InformationⅤ How do USB-C to HDMI Adapters & Cables WorkⅥ How to use USB-C to HDMI Cable?6.1 Preparation6.2 Connect the USB-C plug into your USB-C device6.3 Connect the HDMI end to the display6.4 DoneⅦ HDMI Alt Mode for USB Type-C Connector pageⅧ Why You Should Connect Your USB-C Device to HDMIⅨ Things to Consider When Buying USB-C to HDMI Cable / Adapter9.1 Cable vs adapter9.2 Adapters vs cables9.3 Reliability9.4 Cable length9.5 HDMI Connector Style9.6 Supported Video Resolution9.7 Supported Video Refresh Rate9.8 Available Ports9.9 Compatibility9.10 HDMI VersionⅩ Frequently Asked Questions About USB C to HDMI Ⅰ IntroductionMany laptops and other electronic devices employ USB C connectors, and the trend is for them to have solely USB C as their only type of interface connector. This looks to be a problem when items such as TVs, computer monitors, projectors, and the like only support HDMI, necessitating the need of a means of interface between the two standards. Using a simple cable with a USB-C connector on one end and an HDMI connector on the other is one of the simplest solutions. There are also adapters with a USB-C port on one end and an HDMI cable socket on the other. Ⅱ What is USB-C? USB Type-C, also known as USB-C, is quickly becoming the standard connector for transferring data and power to and from a wide range of computing devices. Its symmetrical design allows it to be placed either way — up or down — removing many of the difficulties associated with previous USB ports and placing it on par with  Apple's reversible Lightning plug. This alone makes it a winner in my book. However, USB-C is still evolving toward faster data transfers and the potential to deliver more power to devices. It's also tightly tied to a number of strong new technologies, such as Thunderbolt and USB Power Delivery, which have the potential to revolutionize how we think about our gear and how we operate in the office, on the road, and at home. But there is a downside. USB-C is merely a connector type; it's based on the Universal Serial Bus specification, which is where things become complicated. The four main USB protocols in use today are, to say the least, perplexing, resulting in an alphabet soup of standards that may confuse even the most technically savvy among us. The specifications are as follows: The USB 3.2 Gen 1 protocol is the most widely used USB specification today. It supports a maximum speed of 5Gbps over a single data lane and can use either an old-school Type-A rectangular connection or the oblong USB-C connector. The next step increase in speed is divided into two options: utilization of double speed data lanes that adhere to the former speed limit (USB 3.2 Gen 1 x2) or a single lane that runs at twice the speed (USB 3.2 Gen 2x1). In either case, the peak throughput is 10Gbps. The USB 3.2 Gen 2x2 standard, which uses two channels of double-speed data flow to reach 20Gbps, is the most current iteration. To add to the confusion, the USB 3.2 single-lane protocols are essentially rebranded USB 3.1 protocols, which may still be found on some devices. USB 3.1 Gen 1 is equivalent to USB 3.2 Gen 1, while USB 3.1 Gen 2 is equivalent to USB 3.2 Gen 2x1. Ⅲ What is HDMI? HDMI is a proprietary audio/video interface that transmits uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital video standard that replaces analog video standards. HDMI adheres to the EIA/CEA-861 standards, which describe video formats and waveforms, the carriage of compressed and uncompressed LPCM audio, auxiliary data, and VESA EDID implementations. HDMI CEA-861 signals are electrically compatible with the Digital Visual Interface CEA-861 signals (DVI). There is no need for signal conversion, and there is no loss of video quality when using a DVI-to-HDMI converter. Consumer Electronics Control (CEC) allows HDMI devices to control each other and allows the user to operate many devices with a single portable remote control device. Since the technology's first debut, other versions of HDMI have been developed and deployed, but all use the same cable and connector. Newer versions contain optional advanced capabilities such as 3D, Ethernet data connection, and CEC extensions, in addition to increased audio and video capacity, performance, resolution, and color schemes. Consumer HDMI products were first manufactured in late 2003. In Europe, either DVI-HDCP or HDMI is included in the HD ready in-store labeling specification for TV sets for HDTV, which was developed in 2005 by EICTA and SES Astra. HDMI first appeared in consumer HDTVs in 2004, followed by camcorders and digital still cameras in 2006. Ⅳ USB-C to HDMI Information To connect a USB C port to an HDMI port, a USB-C to HDMI cable that acts as an adaptor is required. These USB-C to HDMI converter cables are widely accessible and provide a perfect way for laptops and other PCs, among other things, to interface with HDMI-based items such as displays, screens, televisions, and so on. The HDMI Forum, which licenses HDMI technology, decided to build a USB-C to HDMI interface since the USB-C interface is becoming increasingly popular and there is a rising demand to interface to A/V goods such as smartphones, televisions, laptops, and display monitors. Resolutions up to 4K, Audio Return Channel, 3D, HDMI Ethernet Channel, and Consumer Electronic Control are all supported by USB-C to HDMI cables and adapters. Ⅴ How do USB-C to HDMI Adapters & Cables WorkBecause the transmission formats and amount of lines available in USB-C and HDMI are considerably different, the HDMI port must be able to modify its functioning. The HDMI port can use a feature known as HDMI Alternate Mode, or HDMI AM. The cable can interface straight from USB-C to HDMI in this mode. This functionality was added in September 2016, and it enables features up to and including those found in HDMI 1.4b, such as video resolutions up to Ultra HD at 30Hz and Consumer Electronic Control, CEC. Because the connectors for the USB-C connector and the HDMI connector differ, the HDMI port reconfigures the four SuperSpeed differential pairs of the USB-C interface to carry the three HDMI TMDS channels and the clock signal in Alternate Mode. The HDMI Ethernet and Audio Return Channel, as well as the Hot Plug Detect capabilities (HEAC+/Utility pin and HEAC/HPD pin), are carried by the two Sideband Use pins SBU1 and SBU2. The USB-C port then has inadequate pins for the DDC clock, SCL, DDC data, SDA, and CEC. To accommodate these, the three signals are bridged between the HDMI source and sink using the USB Power Delivery 2.0, USB-PD protocol and sent over the USB-C Configuration Channel, CC line. There are a few compromises, as one might expect given that the HDMI Alternate Mode crams the HDMI capability into a smaller number of lines. The first is that the Alternate Mode is based on the older HDMI 1.4b specification rather than the more recent HDMI 2.0b. This means that HDMI Alt Mode for USB-C connections will be able to output up to 4K quality, 3D video, and support HDMI-CEC, but it will not support HDR video or other features introduced in HDMI 2.0b. Ⅵ How to use USB-C to HDMI Cable?6.1 PreparationIt is really simple to use a USB-C to HDMI connection. You only need to take a few steps. 6.2 Connect the USB-C plug into your USB-C deviceConnect the USB-C plug to your tablet, laptop, or smartphone. Check that your host device supports video output, which means the USB-C port must support DP alt Mode! (DP Alt mode: Alternate Mode is a USB Type-C capability that allows video signal transmission.) 6.3 Connect the HDMI end to the displayConnect the HDMI plug to the monitor or screen where you wish the video to be displayed. 6.4 DoneAnd you're finished. Take use of your content on numerous displays. There will be no need for any additional software. Ⅶ HDMI Alt Mode for USB Type-C Connector pageThe HDMI® Alt Mode for USB Type-C TM connector enables HDMI-enabled source devices to connect directly to HDMI-enabled displays via a USB Type-C® connector, delivering HDMI signals and functionality over a single cable without the need for protocol and connector adapters or dongles. This brings together two of the most popular connecting solutions: the tiny form factor, reversible, and multi-purpose USB Type-C connector used by smartphones, tablets, and PC products, and the HDMI connector, which is the dominant display interface with billions of displays installed. Over 355 million HDMI-enabled display devices, including projectors, monitors, VR headsets, and 100% of flat panel TVs, are projected to ship in 2019. HDMI Alt Mode will support the full range of HDMI 1.4b features such as:Resolutions up to 4KSurround soundAudio Return Channel (ARC)3D (4K and HD)HDMI Ethernet Channel (HEC)Consumer Electronic Control (CEC)Deep Color, x.v.Color, and content typesHigh Bandwidth Digital Content Protection (HDCP 1.4 and HDCP 2.2) It is up to manufacturers to decide which HDMI features to support on their USB Type-C products. Ⅷ Why You Should Connect Your USB-C Device to HDMIWith so many options for connecting your phone, tablet, or PC to your TV remotely, why would you invest in a USB-C to HDMI link? Whether you need to mirror portable gaming to your TV or show family and friends your most recent event photos, a USB-C to HDMI connection can basically minimize any lag you might expect from a remote arrangement. Not just that, if your Wi-Fi isn't working or your remote signal is weak, a link implies you can still connect to an HDMI show. Although most brilliant TVs provide a selection of implicit streaming programs, for example, Netflix and Amazon Prime Video, your cell phone can show the same applications through HDMI if your TV does not. Ⅸ Things to Consider When Buying USB-C to HDMI Cable / AdapterBecause the USB-C to HDMI functionality is so convenient, there are numerous vendors on the market producing similar products. This indicates that there is a good selection and that the costs are extremely reasonable. 9.1 Cable vs adapterThere is a wide range of cables and adapters available. Typically, the cable has a USB-C connector on one end and an HDMI socket on the other to connect to HDMI-enabled equipment. The adaptor typically has a USB-C port and a floating HDMI plug. This is then linked to an HDMI wire. These HDMI adapters may be more convenient to use if the HDMI to HDMI cable can be left in place while the adapter is connected to it. The USB-C to HDMI adapters essentially consist of a tiny cable with a female floating socket. Because of their size and weight, they can be relatively easy to transport if an HDMI to HDMI cable is available. USB-C to HDMI cables contain plugs on both ends and will connect the two end points without the use of an additional cable. They are, however, more thick and heavier. 9.2 Adapters vs cablesThere are numerous USB-C to HDMI conversion options available. You can purchase cables with a USB-C connector on one end to connect to your computer and an HDMI connector on the other end to connect straight to the monitor. Another popular solution is to have a USB-C to HDMI adaptor. For this type of transition, a USB-C cable is plugged into the computer, and then an HDMI to HDMI cable is plugged into the adaptor. These adapters might take the form of a small adaptor "box" or a short cable. These can be pretty useful, but they still necessitate the usage of an HDMI connection. Check what you want, how much it will cost, and whether you already have an HDMI to HDMI cable or whether you would need to get one. 9.3 ReliabilityIt is never easy to assess the dependability of anything. However, as in many other cases, you get what you pay for. Having said that, most adapters and cables will function well and give enough service. Obviously, if the USB-C to HDMI cable or converter is frequently used, it is more likely to fail. Lots of connector insertions and cable flexing, especially at vulnerable locations, will shorten the cable's life. The cable's durability will be an important factor in its dependability. The cable quality may be significant in situations where it will be subjected to a lot of wear. Nylon encased cable is becoming more common, and it is reasonably simple to use for manufacturers. Nylon is both cheap and good in protecting wires in a variety of ways. Many folks who want to use these USB-C to HDMI cables on the go may find this to be an option. Another thing to keep an eye out for is the connectors' construction. Aluminium connectors can be more durable than basic plastic connectors, which can shatter more quickly. Consider the overall robustness of the cable assembly, which can be difficult to determine in many cases, especially online. 9.4 Cable lengthThe length is especially crucial if a cable with USB-C on one end and the matching HDMI to connect directly with the monitor, display, screen, etc. is used. Cables are typically one metre, two metres, or the equivalent in feet, so ensure that the cable is the suitable length for the job. It is frequently helpful to run some string between the two items to be connected and then measure the length of this string. Allow for a little more time because distances are frequently longer than you expect. However, there is a fine line between allowing for a little more and having too much that must be neatly coiled away somewhere. 9.5 HDMI Connector StyleAlmost all USB-C to HDMI cables and adapters use a standard type A HDMI connector. However, certain USB-C to HDMI adapters are available with different connector sizes, including regular HDMI, mini-HDMI, and micro-HDMI. This appears to be the best approach for the time being, though there are certain to be some USB-C yo small or micro-HDMI cables somewhere. 9.6 Supported Video ResolutionResolution is an important aspect of any digital information, whether it's a movie, a video clip, or even an image. The resolution is essentially a scale that indicates how much space the digital information takes up on the display panel. As you can expect, the panel's video resolution capabilities must be equal or higher in order to handle the video content. However, this is no longer a major issue because even low-cost monitors and TVs can support 4K resolution or at least a QHD 1440p resolution screen. Even if you use such high-end display devices, you won't obtain the same results if your adapter limits the resolution. We've listed the video quality supported by each of our adapters so you don't have to worry about its compatibility with your setup. 9.7 Supported Video Refresh RateAnother critical component is the refresh rate of the video broadcast. When you play a video game on your display, it is rendered at a specific FPS, or frames per second. These frames are displayed on your screen based on their refresh rate. If your display has a refresh rate of 60 Hz, you will only see 60 FPS even if you are playing the game at a higher FPS. Furthermore, if you include extra components in the equation, such as a USB C to HDMI adapter, you must ensure that the adapter is capable of transferring material at such a high refresh rate. If you do not, you will notice a considerable decrease in video transmission and the video stream will appear more slower and stuttery than on your original display. If you're looking for a USB C to HDMI adapter for gaming, ensure sure it has a refresh rate of at least 60 Hz. However, 30 Hz is plenty for watching movies and TV programmes. 9.8 Available PortsThe USB C to HDMI adapter's available ports are also crucial to its functionality. The input for these adapters will always be a USB C connection. However, depending on the sort of adapter you purchase, there may be a single or several outputs. You can only use your adapter for display connections if it has a single HDMI port or cable connection. However, because many laptops offer USB C as a universal connector for numerous functions, you may want a USB C to HDMI converter with multiple outputs. There are a few premium choices on the market that provide display connection compatibility as well as additional data transfer ports. There are also a few choices for multi-monitor configurations. 9.9 CompatibilityMake sure your USB-C to HDMI cable is compatible with your device before purchasing it. You should also keep in mind that the USB-C port on your device supports DP Alt Mode. DisplayPort Alternate Mode is a useful expansion of the USB-C connector that allows it to connect to another monitor directly. 9.10 HDMI VersionWhen HDMI Alternate Mode was first released, it only supported functionality up to Version 1.4b. As a result, when using a USB-C to HDMI connection or adapter, this should be considered. Ⅹ Frequently Asked Questions About USB C to HDMI1. How many Volt is a USB port?A standard USB 1.0 or 2.0 socket contains four pins, and a USB cable contains four wires. The inside pins convey data (D+ and D-), while the outside pins supply power (5 volts). USB 3.0 ports add an extra row of five pins, resulting in USB 3.0-compatible connections with nine wires. 2. Is a USB port AC or DC power?For charging solely, standard USB devices have a 5 V dc voltage and a current of up to. 5 A or 500 mA. This is what allows them to coexist with your computer's USB ports. Most USB wall adapters will be 5 V adapters with current ratings far in excess of. 3. How do I connect a USB to my computer?Insert the flash drive into your computer's USB port. A USB port should be located on the front, rear, or side of your computer (the location may vary depending on whether you have a desktop or a laptop). A dialog box may display depending on how your machine is configured. If so, choose Open folder to view files. 4. Where is USB port on computer?Most USB ports on desktop computers are located on the rear of the computer casing. In general, you should connect your mouse and keyboard to these ports while leaving the front USB ports free for digital cameras and other devices. 5. How do I connect a USB to my phone?(1)Connect a flash drive (or SD reader with card) to the adapter's full-size USB female end. (2)Connect the USB-C end of the cable to your phone. (3)Swipe down from the top of the screen to see the notification shade. (4)Select USB Drive. (5)To view the files on your phone, tap Internal Storage. 6. How to use a USB C to HDMI adapter?It is simple to use a USB C to HDMI adapter. In fact, it is as simple as inserting the connectors into the appropriate port. Simply connect the adapter to your laptop or any other USB C source, and then connect the adapter to an HDMI TV or monitor using an HDMI cable. Some connectors also have an HDMI output cable, so you won't need an HDMI cable at all. Most importantly, no driver is required to use these adapters. 7. Is there quality loss between USB C and HDMI?When you use an adaptor, you risk losing quality. However, when it comes to USB C to HDMI adapters, the quality is nearly non-existent. The high data transmission rate offered by both USB Type C and HDMI is the primary reason for this. If you choose a premium option, you can even obtain up to 4K resolution output at a refresh rate of 60 Hz, if not higher. As a result, these adapters are perfect for gaming-related applications. 8. Is using an adapter better than a direct connection?As previously stated, there is almost little quality loss in these adapters. As a result, instead of a direct connection, you can use these adapters. However, if your laptop has an HDMI or DisplayPort port, we prefer using a direct connection because it eliminates the need for an additional device between the source and the monitor. Direct connections are also significantly more reliable than adapters because there are fewer chances of loose connections. 9. What are the 5 wires in a USB cable?Red, black, white, and green are the most common hues found on the interior of USB cables. Each of these colors shows whether the wire is for charging or data transfer. Although the traditional wire colors in a USB cable are red, black, white, and green, don't be concerned if your cable does not have these colors. 10. Does a USB cable draw power?When plugged in, USB cables and chargers use very little energy and are safe even when the car is turned off. However, this is dependent on whether a gadget is charging, whether electricity continues to run even when the car is turned off, and how long the car will sit before being restarted. 

IntroductionIn electronics, a pinout (sometimes written "pin-out") is a cross-reference between the contacts, or pins, of an electrical connector or electronic component. It describes the functions of transmitted signals and the circuit input/output (I/O) requirements. The number of pins is divided into 8-pin, 14-pin, 16-pin, etc. Every pin must be properly matched to a connector that has the same function. Pinout types include Universal Serial Bus (USB) pinout, PS/2 pinout, ATX power supply pinout, VGA pinout, and Digital Visual Interface (DVI).How to Read Pinouts?CatalogIntroductionⅠ Pinout Arrangement DescriptionⅡ Arduino Pinout and Raspberry Pi Pinout2.1 Arduino Nano Pinout and Arduino Uno Pinout2.2 Arduino Pinout Series2.3 Raspberry Pi Pinout and Diagram2.4 Difference between an Arduino and a Raspberry PiⅢ Example: AT89S52 PinoutsⅠ Pinout Arrangement DescriptionA pinout generally has descriptions in a diagram or table, which specifically indicates whether it is the back-side or front-side view, or if it is the mating face of the connector, or it stands for? Generally speaking, the more pins, the larger the size of the IC chip, the stronger the circuit function, and of course, the higher the price.What these pins stand for? Look at the following Common PIC Pin Descriptions:Pin NumberSymbolDescription1AUDIOAudio Signal Output2FM OUTFM Detection Output3IF AGCIF Signal Input4RF AGCRF AGC Voltage Output5IF INIF Signal Input6IF GNDIF Circuit Ground7IF VccIF Circuit Power Supply8FM FILTERFM Detector Filter Terminal9AFT OUTAFT Control Power Output10SDAI2C Bus Data Terminal11SCLI2C Bus Clock Terminal12ABLAutomatic Brightness Control13R INRed Character Input14G INGreen Character Input15B INBlue Character Input16BLACK INCharacter Blanking signal Input17RGB VccDecoding Circuit Power Supply18R OUTRed Primary Color Signal Output19G OUTGreen Primary Color Signal Output20B OUTBlue Primary Color Signal Output21IDWhite Balance Adjustment Signal Input22VER OUTField Sawtooth Wave Output23V RAMP ALCField Sawtooth Wave Formation24H/BUS VccLine Start Power25AFC FILTERLine AC Low-pass Filtering26HOR OUTLine Excitation Pulse Output27FBP INLine and Reverse Pulse Input28REFReference Current Formation29CLK OUT4MHz Clock Signal Output Pin NumberSymbolDescription301H DL VccBuilt-in Baseband Delay Line +5V Power Supply311H DL Vcc OUTBaseband Delay Line Boost Circuit Output Terminal321H DL GNDBaseband Delay Line Ground33SECAM INComponent Signal Input34C APC FILTERChroma Subcarrier Phasedetector (APC1) Low-pass Filter35SECAM INTERFACE4.43MHz CW Signal Output or SECAM Achromatic Signal Input36X TAL4.43MHz Crystal Terminal37SEL VIDEO OUTVideo Output38V/C/DEF GNDGround39EXT V IN/Y INAV Video or Y Signal Input Terminal40V/C/DEF VccVideo/Chroma/Scan Part Power41INT V IN/C INAV Video or C Signal Input Terminal42BLACK STECHFilter End of Black Level Extension Circuit43VIDEO OUTVideo Detector Output44VCO FILTERIF Lock Detection Filter45VCOExternal VCO Resonant Network46PIF APCIF APC Filter47EXT AUDIO INAV Audio Signal Input48SIF OUTAudio Accompanying Sound IF Output49SIF INAudio Accompanying Sound IF Input50SND APCAccompanying Sound Discrimination Filter Pin NumberSymbolDescription1BASSBass Control Output2MUTEMute (High Level) Control Output350/6050Hz/60Hz Identification Output4SECAMSECAM Recognition5VOLVolume Control6COMB.FDigital Filter on/off Control7POWERPower On/Standby Control8TUNEPWM Tuning Voltage Output9GNDGround10XTAL132kHz Crystal Connection Terminal11XTAL232kHz Crystal Connection Terminal12VDDPower Supply13KEY-IN1Key Scan Signal Input 114KEY-IN2Key Scan Signal Input 215AFT-INAFT Control Voltage Input16RESETReset Terminal17FILTERCharacter Oscillation Low Pass Filter18NCEmpty Pin19V-SYNCCharacter Vertical Positioning Pulse Input20H-SYNCCharacter Horizontal Positioning Pulse Input21OSD-BLKCharacter Blanking Pulse Output22SDAI2C Bus Data Terminal23SCLI2C Bus Clock End24SAFTYOverload Detection Terminal25CSProduction Debugging Chipselect Signal Input Terminal26REM INRemote Control Signal Input27SIFAudio IF Switching Control28TV/AV1AV/TV Switch29TV/AV2AV/TV Switch303.58/4.433.58/4.43 Control31UHFUHF Band Control32VHVHF-H Band Control33VLVHF-L Band ControlⅡ Arduino Pinout and Raspberry Pi Pinout2.1 Arduino Nano Pinout and Arduino Uno PinoutThe Arduino Nano is a small, complete, and breadboard-friendly board. It is based on the ATmega328 8-bit microcontroller by Atmel. It has a total of 36 pins. Out of these 8 are analog input pins and 14 digital input/output pins (of which 6 can be used as PWM outputs). Nano has a 16 MHz SMD crystal resonator, a mini USB-B port, an ICSP header, 3 RESET pins and, a RESET button. The Arduino digital pins can read/output only two states: when there is a voltage signal and when there is no signal.Figure 1. ATMEGA328 PinoutArduino UNO is based on the ATMEGA328 by Atmel. The Arduino UNO pinout consists of 14 digital pins, 6 analog inputs, a power jack, USB connection and ICSP header. The function of Analog pins is to read the value of the analog/digital input used in the connection.Figure 2. Arduino UNO Pinout2.2 Arduino Pinout SeriesDigital PinsPower:  Mini USB  VinICSP:  MISO (Master In Slave Out)  Vcc (Supply Voltage)  SCK (Clock from Master to Slave)  MOSI (Master Out Slave In)  RST (Reset (Active Low)  GND (Supply Ground)Serial Communication PinsPWM (Pulse Width Modulation) PinsExternal InterruptsSPI (Serial Peripheral Interface) pinsBlinking LED Analog PinsRESETI2C ProtocolAREF (Analog Reference) PinsPower2.3 Raspberry Pi Pinout and DiagramThe Raspberry Pi is a tiny and affordable computer that you can use to learn programming through fun, practical projects, which is the go-to microcomputer for all ages and abilities. You can plugs it into a computer monitor or TV, and uses a standard keyboard and mouse. Over the years the header has expanded from 26 pins to 40 pins while maintaining the original pinout. As you can see, the Pi not only gives you access to the bi-directional I/O pins, but also Serial (UART), I2C, SPI, and even some PWM ("analog output").Figure 3. Raspberry Pi GPIO PinoutRaspberry Pi is as small as the size of a credit card, and works as if a normal computer at a relatively low price. It is possible to work as a low-cost server to handle light internal or web traffic. What’s more, grouping a set of Raspberry Pi to work as a server is more cost-effective than a normal server. Although Raspberry Pi board has so many advantages, it also has the following disadvantages:1) Not able to run Windows Operating system2) Impractical as a Desktop Computer3) Graphics Processor Missing4) Missing eMMC Internal Storage2.4 Difference between an Arduino and a Raspberry PiThe main difference between them is: Arduino is microcontroller board, while Raspberry Pi is a microprocessor based mini computer (SBC). The Microcontroller on the Arduino board contains the CPU, RAM and ROM. ... Raspberry Pi needs an Operating System to run. Arduino doesn't need any operating system.If you're coming to the Raspberry Pi as an Arduino user, you're probably used to referencing pins with a single, unique number. Programming the Pi's hardware works much the same, each pin has its own number...and then some.Ⅲ Example: AT89S52 PinoutsThe pin functions of AT89S52 are diverse. For example, the intermediate frequency signal can be demodulated from the pin to the internal FM circuit in an unbalanced manner. At the same time, it is also the control pin for AV\TV conversion and PAL, NTSC, SECAM chroma system conversion in the block, and its input impedance is about 3.4K.Figure 4. AT89S52 Pinouts1) For Recognition OutputThe pin outputs image recognition signal in OC gate mode. When the video TV signal has been received, this pin presents high impedance to the outside, and a high level signal can be obtained through an external pull-up resistor; when no signal is received, this pin presents a low impedance and outputs a low level.2) As APC1 Filter TerminalThe chip generates a 38MHz switching signal in an oscillating manner to complete the demodulation of the image IF signal. Whether the generated switching signal is accurate depends on the automatic phase control circuit (APC) control. Among them, the filtering of the APC1 error signal is completed on this pin.3) As APC2 Filter TerminalThe filter terminal of the second-stage APC circuit4) An external pin for the quartz crystal oscillatorThe external quartz crystal and internal circuit will oscillate in the form of series resonance. The oscillation frequency is a quarter of the carrier frequency of the image intermediate frequency signal. The frequency of the quartz crystal required is different under different signal systems.5) For AFT Signal OutputThe image IF signal compare with the internal frequency, and then the pin outputs AFT error signal.6) Full TV Signal OutputThe signal in the image is demodulated, and finally the video signal and the accompany audio intermediate frequency signal are output from the pin, and the output signal level is 2V.7) Radio Frequency AGC Delay AdjustmentBy adjusting the external potentiometer, the AGC delay amount can be adjusted.8) For the Input of Internal and External Video SignalsThe signal input needs to be separated from the DC. The coupling capacitor capacity is 1uF. When the internal input level is the peak, the max value is 2V. And when the external input is the peak and the peak is 1V. The input impedance is about 50kΩ. Inside the integrated circuit, the blanking level is fixed at 4.5V.9) The Output of Contrast Control Voltage can also be used to control ACL.10) The pin is the standard level of the built-in filter and the switch of S-VHS. It needs a 1Uf capacitor to be grounded to set the standard level. When it is in the S-VHS mode, the pin voltage must be led by an external circuit is set below 2V. When it is in the normal AV state, the voltage level should be set above 2V.11) Input Pin for S-VHS Chroma Signal and DC ControlWhen inputting chroma signal, a 0.01Uf capacitor should be used to cut off the DC input. At PAL format, the chroma signal level should be 300mV peak-to-peak, and should be 286mV peak-to-peak under the NTSC system.12) As a Delayed Video Signal OutputIt can also achieve ABL control. The output video signal level is 2V peak-to-peak, and a current of 0.5mA or more is necessary.13) The Output of the Decolorization ControlAfter the internal decolorization circuit is activated, a low-level signal will be output from the pin.14) Address Input for Analog Bus Control15) Data Input of Analog Bus Control16) The Output of the Internal Field Scanning PulseThe external resistance value can set the sensitivity of the internal field synchronization separation. If you don't need the internal field pulse, you can also input other field pulse signals from the pin, and the internal field output is automatically cut off at this time. The pin can also be an automatic trigger mode release switch and a row AFC strobe release switch.17) To connect the oscillating quartz crystalThe crystal frequency should be 500Hz.18) Separate power supply pins for line oscillation and line pre-excitation circuits. A higher voltage provides a DC voltage to the pin through a resistor, which is stabilized to 7V by the internal voltage regulator circuit for use by the above circuits. The selection calculation of resistance is: R1=(+B1－7.0V)/13mA.19) The output of line pre-excitation pulse is output in push-pull mode.20) Line and Reverse Pulse InputThe line and reverse pulse signal is output from this pin after forming a sand castle pulse internally. As a unified working sequence of some circuits, this pin is also the output of the integrated circuit pulse in the SECAM system.21) Character Background Blanking Pulse InputThe standard control voltage is 1V, when the input voltage is higher than 1V, the image display stops, and the character is displayed at the current position. When the pin voltage is lower than 1V, the image is displayed at the current position.22) The input of the three-color signal of the on-screen character display (OSD). When using the analog character display mode, the DC input needs to be cut off. When using the digital character display mode, the high level needs to be set to a certain value.23) Negative brightness signal output, and at the same time the input of the de-trap signal.24) Color difference signal output, respectively output the R-Y, G-Y, B-Y of the TV image or the R, G, B three-color screen character display dot matrix after character display conversion.25) After the input of the ALC amplifier (CCD delay adjustment) is delayed and calculated by the integrated one-line delay line, the two color difference signals return to the LA7687 from these two lead pins.26) Output the Color Difference Signal to the Integrated Delay Line.In the PAL system, the two incompletely demodulated color difference signals are output from two pins to the delay line for further processing. When in the SECAM system, the color difference signal does not come from LA7687. Therefore, the two pins present a high impedance state under this system, and the output dc voltage is 3.6V.27) The subcarrier recovery circuit needs to be connected to 4.43MHz and 3.58/MHz quartz crystals.28) For the Color Demodulation Circuit APC FilterThe filter composed of the external resistance container can set the synchronization range of the subcarrier oscillation.29) The AGC Filter Pin of the First Stage Mid AmplifierThe AGC detection circuit separates the synchronization signal by detecting the peak value of the video signal, and filters it into the AGC voltage at the pin. The second stage AGC filter is hidden inside the integrated circuit.30) Image IF Signal InputThrough the surface acoustic filter to form a specific image IF signal, in a balanced way from  two lead pins amplify the collector circuit. Inside the integrated circuit, there are a total of three amplifiers, and the total amplification gain is above 60dB.31) The output of the radio frequency AGC is output in an open-collector mode.32) Audio Signal OutputThe integrated circuit completes the demodulation of the FM signal, and the audio signal is output from the pin, and there should be a de-emphasis circuit composed of resistive components on the outside.33) Audio Filter PinIt is used to eliminate the DC feedback of the preamplifier, in addition, a 1uF capacitor is required to be connected externally. In addition, when this pin is set to high level, the image IF gets into the SECAM mode. Frequently Asked Questions about Electronic Pinout1. What does pinout mean?In electronics, a pinout (sometimes written "pin-out") is a cross-reference between the contacts, or pins, of an electrical connector or electronic component, and their functions. "Pinout" now supersedes the term "basing diagram" that was the standard terminology used by the manufacturers of vacuum tubes and the RMA. 2. What is pin configuration?Devices support both analog input and digital I/O line modes on several configurable pins. The following table provides typical parameters for the pin configuration commands (D0 - D9, P0 - P2). 3. What is a pinout cable?Pinout or pin-out is a term used in electronics to describe how an electrical cable is wired, or the function of each wire (pin) in a connector. An electrical connector typically consists of several electrical contacts or pins that can be used to carry electrical power or signals. 4. What are the pins on Arduino Uno?Arduino/Genuino Uno is a microcontroller board based on the ATmega328P (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header and a reset button. 5. How many digital and analog pins are in Arduino Uno?Microcontrollers

IntroductionIn-memory computing (IMC), a technique of future computing, stores data in RAM to run calculations entirely in computer memory. With the rise of the big data era, faster data processing capabilities are required. Computer memory and storage space are also growing exponentially to adapt to large-capacity data collection and complex data analysis, which promotes the development of AI (artificial intelligence), and then derives emerging stuff, that is, in-memory computing.In-memory Computing (IMC) ExplainedCatalogIntroductionⅠ Memory Wall: Processor /Memory Performance GapⅡ Developing RequirementⅢ What Is In-memory Computing?3.1 In-memory Computing Definition3.2 Four Realization MethodsⅣ Driving Force of In-memory Computing and Market Prospects4.1 In-memory Computing for AI4.2 In-memory Computing Product Outlook4.3 In-memory Computing Market and ProspectⅤ ConclusionⅠ Memory Wall: Processor / Memory Performance GapThe von Neumann architecture has occupied the dominant position in computer system when the computer invented. This kind of calculation method is to store the data in the main memory first, and then fetch the instructions from the main memory to execute them in order when running. We all know that if the connecting speed of the memory cannot keep up with the performance of the CPU, the computing will be limited. This is a memory wall. At the same time, in terms of efficiency, the von Neumann architecture also has obvious shortcomings. It consumes more energy to read and write data than to calculate once time.Figure 1. Von Neumann Architecture DiagramThe performance of computer processors has developed rapidly based on Moore's Law, and has been directly improved with the invention of transistors. The main memory of the computer uses the DRAM. It is a high-density storage solution based on capacitor charging and discharging. Its performance (speed) depends on two aspects, namely the reading/writing speed of the capacitor charging and discharging in the memory and the interface bandwidth between the devices. The read/write speed of capacitor charging and discharging has increased with Moore’s Law, but the speed is not as fast as the processor. In addition, the interface between DRAM and the processor is a mixed-signal circuit, and its bandwidth increasing speed is mainly restricted by the signal integrity of the traces on the PCB. This has also caused the performance improvement of DRAM to be much slower than that of the processor. At present, the performance of DRAM has become an huge bottleneck of overall computer performance, the so-called "memory wall".  It blocks the computing performance improvement.Figure 2. Moore's Law Effect Ⅱ Developing RequirementIn the current AI technology, with the increasing amount of data and calculations, the original von Neumann architecture is facing more and more challenges. Rely on expanding CPU, the hardware architecture can’t have a large amount of calculation. Also the larger storage capacity is heavily rely on the past architecture, it is also very unsuitable for AI. When the memory capacity is large to a certain extent, it can only show that certain technologies need innovation. In order to solve the "memory wall" problem, future computers are not based on computing memory, but the in-memory computing, thereby reducing the cost of data access in the calculation process.Figure 3. Conventional Computing vs In-memory Computing Ⅲ What Is In-memory Computing?3.1 In-memory Computing DefinitionIn-memory computing (or in-memory computation) is a technique based on RAM data storage and indexing, which proposed by the MIT research group, and its main purpose is to accelerate the convolution calculation. We know that convolution calculations can be expanded into weighted accumulation calculations. From another perspective, it is actually a weighted average of multiple numbers. Therefore, the circuit realizes the weighted average of the charge domain. The weight (1-bit) is stored in SRAM, and the input data (7-bit digital signal) becomes an analog signal through the DAC. According to the corresponding weight in the SRAM, the output is multiplied by 1 or -1 in the analog domain, which averaged in the analog domain, and finally read out by the ADC as a digital signal. Specifically, since the weight of the multiplication is 1-bit (1 or -1), it can be controlled by using a switch and a differential line simply. If the weight is 1, the capacitor on the side of the differential line is charged to the required output value. Otherwise, let the other side of the differential line be charged to this value. As for average, connect several differential lines together in the charge domain.Of course, there is more than one circuit for in-memory calculation, and the calculation accuracy is not limited to 1-bit. However, we can see the above examples that the core idea of in-memory calculations is generally to convert calculations into weighted calculations. Store the weights in the memory unit, then modifications on the core circuit of the memory (such as the readout circuit) are made. So that the process of reading is like a process in which the input data and weights are multiplied in the analog domain, that is, convolution. Because convolution is a core part of AI and other calculations, in-memory computing can be widely used in such applications. In-memory computing uses analog circuits for calculations, which is the difference compared with traditional digital logic calculations.In more traditional architectures, there are some multiply-accumulate circuits (MAC) for tensor math, especially the matrix multiplication. These architectures attempt to arrange the MAC in a way that moves weights and activations to the appropriate location. Activations are calculated from the previous neural network layer. Multiplication usually involves activations and weights, both must be moved to the place where multiplies them. In-memory computing makes use of it. Therefore, if the weights are stored in memory, the memory can access through activations to obtain multiplication and accumulation. The only difference from the actual memory is that the in-memory computing concatenates all word lines at once, instead of decoding the input to get one word line only.Figure 4. In-memory Computing Diagram3.2 Four Realization MethodsThe attempt is to enter the analog domain and treat the storage unit as an analog unit instead of a digital unit to reduce consumption. We have already got a way to use simulation on the front end of the inference engine. That is in-memory computing. Therefore, we take digital data, using a DAC to convert it to an analog value, and then driving a memory with these analog content to obtain an analog bit-line output, finally using an ADC to convert the result back to a digital format. However, the in-memory computing is still in the exploratory stage, and there are many specific implementation methods to study, currently there are three types: RRAM, Flash, SRAM, and DRAM.Based on RRAMRRAM is the most common method of doing this, because it is easy to use by applying Ohm's law to a series of resistors, but it still has the problem of relying on RRAM. The relationship between programming and resistance is non-linear, which requires more work to be done to make viable calculation circuits in RRAM memory for market. So it is just an idea, and the specific plan is still under study. Based on FlashNOR Flash memory has a more traditional word-line/bit-line structure. It is both resistive and capacitive. Generally, the memory cell is a transistor that is turned on or off. However, if it is partially conductive, it can be used as a resistor. The resistance depends on the amount of charge on the floating gate of the memory cell (capacitor). When running all the time, the cell will conduct to its maximum capacity. During this process, it does not conduct at all, however, it can be partially programmed. There is a problem is that you cannot precisely control the number of electrons. Moreover, the response to any number will vary with the process and temperature and other variables.Two companies are studying this method. Microchip owns their memBrain array, thanks to their acquisition of SST, and Mythic is a start-up company dedicated to an inference engine that uses in-memory computing with flash memory. Both companies said that they are using extensive calibration techniques to deal with this change.Another issue, flash cells will lose electrons over time. Electrons will flow around, which brings up an interesting topic: on this type of memory array, data retention and durability will be like.From the application point of view, it depends on whether it is to be used in cloud computing or edge inference engine. At the edge, it may perform certain fixed reasoning functions throughout the life cycle of the device. Therefore, if there are enough arrays, then you will load the weights for the first time and don't need to program it anymore (unless you do a update), because the flash memory is non-volatile. Although you still need to move activations, there is no need to move the weights, which will be stored permanently in the array. This would indicate that data durability (number of times the device can be programmed before cumulative damage accelerates electron leakages to an unacceptable level) does not matter, it only need to program once.In contrast, in cloud applications, the device is likely to be shared as a general-purpose computing resource, so this requires reprogramming for each new application. This means that battery life becomes more important in the cloud. Mythic claims to have a 10K write cycle, and has observed that even if it is reprogrammed every day, it will last for more than 10 years.If set an analog value for it and use an analog value in the cell, then in theory, each electron is important. However, if there is enough electron migration, you need to refresh the storage unit, or compensate for electrons change in some way. Because the same analog input today will produce different results than a year ago. The calibration circuit can also deal with some aging problems. However, for data retention, Mythic said they do perform regular updates of the weight values stored in flash memory. This will make persistence the main wear-out mechanism rather than data retention. Microchip stated that its data retention time is TBD, but it is likely to reprogram the device quarterly or annually to restore the unit.So they need a large number of high-quality ADCs and DACs to keep the signal-to-noise ratio (SNR) within a scope of accurate reasoning, which is the focus of designing work. Mythic claims that they provide a novel ADC, so that Microchip can share it to reduce the number required. Although ADC does consume energy, it also greatly reduces overall system consumption. Based on SRAMThis idea came from a lecture at Hot Chips at Princeton University. By definition, SRAM is a bistable unit. Therefore, it cannot be in an intermediate state, how should this be handled? And the DACs and ADCs that need to be corrected more over than the array in terms of area and power consumption.The point of this problem boils down to the question of how to simulate. They explained that this method uses more than one-bit line for calculation. Since the unit is still a digital value, it takes several bit lines to perform a calculation. The bit line can be split, and different groups perform different multiplications. The following figure illustrates it.Figure 5. Bit LineWith 8 inputs at a time, so the input vector is sliced and several consecutive multiplications are carried out to obtain the final results. The bit line charge is deposited on the capacitor. When ready to read, the charge is read out and sent to the ADC for conversion back to the digital domain. Their basic unit structure is as follows:Figure 6. Bit CellThese capacitors may affect chip size issues, but they said that the metal above the cell can be used. Of course, one cell is now 80% larger than the standard 6T SRAM cell (even without capacitors), but they say that their overall circuit is still much smaller than a required circuit based on standard digital implementation. In addition, since their basic array operations are still in digital form, they are less sensitive to noise and changes, which means their ADCs can be simpler and consume less power.Figure 7. Chip SizeBased on DRAMThis idea refers to not using a lot of power to obtain DRAM content, and in some way incorporate calculations into the CPU or other computing structures and directly run it on the DRAM die, which is what UPMEM does. A simple processor is built on the DRAM die, also the architecture will not compete with Xeon chips, they call this set "processing in memory" or PIM.Figure 8. PIM ChipInstead of bringing data to calculations, they bring calculations to data. The runtime is performed by the CPU in DRAM chip. That is, there is no need to move the data to any location outside of the DRAM chip, just send the calculating result back to the host system. Also, since ML calculations usually involve a lot of reduction, less data required for calculations. Although this does require some minor changes to the DRAM, they did not change the manufacturing process. Under this case, a standard DRAM module will provide multiple opportunities for distributed computing. At the same time, it becomes complicated to use this function to write a program.They said that a server using PIM offload will consume twice as much power than a standard server connected to a DRAM module without PIM. However, with a throughput of 20 times, it still provides them with a 10 times energy efficiency advantage. In addition, this method can help defend against side-channel security attacks. Thus a group of computing threads originally contained in one or more CPUs flows to DRAM. Therefore, it is necessary to check all DRAMs and figure out where thread is in some way, but this will be a difficult task. Ⅳ Driving Force of In-memory Computing and Market Prospects4.1 In-memory Computing for AIPeople have recognized the problem of "memory wall" for a long time, but why is in-memory computing only raised in the past two years? So we have to analyze the boost behind its rise.The first motivation is the rise of AI based on neural networks, especially the hope that AI can be popularized in mobile and embedded devices. So that in-memory computing with a high energy efficiency ratio has attracted attention. In addition, neural networks have a high tolerance for errors in calculation accuracy. Therefore, errors introduced in simulation calculations of in-memory computing can often be accepted. That is to say in-memory computing and AI are good partners for each other.The second motivation is the new memory. For in-memory computing, the memory characteristics often determine the efficiency of in-memory computing. Therefore, new memories improvement will often drive the development of in-memory computing. For example, the recently popular ReRAM uses resistance modulation to store data, so the readout of each bit uses a current signal instead of a traditional charge signal. In this way, it is a very natural operation for current to accumulate (combining several currents directly to achieve the sum of currents, even without additional circuits). That is to say, ReRAM is very suitable for in-memory calculations. From the perspective of memory promotion, new memories are also willing to catch up with the AT trend. Therefore, new memory manufacturers are also happy to see in-memory computing based on their own memories to accelerate AI development, which will broaden the memory market. 4.2 In-memory Computing Product OutlookChip products for in-memory computing are expected to come in two forms. The first form is sold as a memory IP with computing functions. Such memory IP may be traditional SRAM, or new memory such as eFlash, ReRAM, MRAM, and PCM.The second form is to directly build AI acceleration chips based on in-memory calculations. For example, Mythic plans to make PCIe accelerator cards based on flash memory, that is, access data with the main CPU through the PCIe interface. The weight data is stored on the Mythic memory chip, so that when the data is sent to the Mythic IPU, the calculation can be directly read out. In this way, the action of reading the weights data is eliminated.Figure 9. Mythic is a Pcie Accelerator 4.3 In-memory Computing Market and ProspectWhat impact will in-memory computing have on the AI chip market? First of all, we see that in-memory computing uses analog calculations, so its accuracy will be affected by the low signal-to-noise ratio. Usually the upper limit of accuracy is about 8-bit, and it can only do fixed-point calculations not the floating-point calculations. So in-memory computing is not suitable for the AI training market that requires high calculation accuracy. In other words, the main battlefield of in-memory computing is the AI inference market. For example, it is more suitable for embedded artificial intelligence, which has high requirements for energy efficiency not the accuracy. In fact, in-memory computing is actually most suitable for occasions where large memory is needed. For instance, flash is inherently required in IoT and other scenarios, so if you can add the in-memory computing to flash, it is quite suitable. However, introducing in-memory computing in a large storage memory may not appropriate. Based on this analysis, we believe that in-memory computing may become an important part of embedded AI (such as smart IoT) in the future. Ⅴ ConclusionWith the rise of AI and new memories, in-memory computing has also become a new hot spot. Based on the unique characteristics of the memory, it combines with analog calculations in memory, thereby greatly reducing the memory read and write operations in AI. Although the accuracy of calculation in the memory is limited by analog calculation, it is also suitable for embedded AI applications that pursue energy efficiency most and can accept a certain loss of accuracy. Frequently Asked Questions about In-Memory Computing Technology1. Why do we need in memory computing?In-Memory Computing provides super-fast performance (thousands of times faster) and scale of never-ending quantities of data, and simplifies access to increasing numbers of data sources. 2. What does in memory mean?An in-memory database is a type of purpose-built database that relies primarily on memory for data storage, in contrast to databases that store data on disk or SSDs. ... Because all data is stored and managed exclusively in main memory, it is at risk of being lost upon a process or server failure. 3. How does in memory computing work?In-memory computing means using a type of middleware software that allows one to store data in RAM, across a cluster of computers, and process it in parallel. Consider operational datasets typically stored in a centralized database which you can now store in “connected” RAM across multiple computers. 4. What is in memory computing in SAP HANA?An In-Memory database means all the data from source system is stored in a RAM memory. In a conventional Database system, all data is stored in hard disk. It provides faster access of data to multicore CPUs for information processing and analysis. 5. How is data stored in memory?Normally memory is described as a storage facility where data can be stored and retrieved by the use of an address. This is accurate but incomplete. A computer memory is a mechanism whereby if you supply it with an address it delivers up for you the data that you previously stored using that address. 6. What is in memory data processing?In-memory processing is the practice of taking action on data entirely in computer memory (e.g., in RAM). ... Since the storage appears as one big, single allocation of RAM, large data sets can be processed all at once, versus processing data sets that only fit into the RAM of a single computer. 7. What is in memory database processing and what advantages does it provide?The major advantage of systems using in-memory databases vs traditional database systems is: its performance speed. ... Source data is loaded into the system memory in a compressed and format. Therefore, in-memory processing reduces disk seek time for accessing data and streamlining the work involved in processing queries. 8. What is big data computing?Big data computing is an emerging data science paradigm of multi dimensional information mining for scientific discovery and business analytics over large scale infrastructure. ... Big data is characterized by 5V's such as volume, velocity, variety, veracity, and value.