asic Related Articles

Ⅰ Introduction   A capacitor is an electrical device that stores energy as an electric field. It consists of two metal plates separated by a dielectric or non-conducting material. Fixed capacitance and variable capacitance are the two broad categories of capacitors. The most common are fixed capacitance capacitors, but variable capacitance capacitors are also available. Rotary or trimmer capacitors are examples of these. Fixed capacitance capacitors are classified as film capacitors, ceramic capacitors, electrolytic capacitors, and superconductor capacitors. Follow the link to learn more about the various types of capacitors. This article goes into greater detail about the ceramic capacitor.     Images of  Capacitors     Catalog Ⅰ Introduction Ⅱ Ceramic Capacitor Basics 2.1 What is a Ceramic Capacitor? 2.2 Ceramic Capacitor Polarity and Symbol 2.3 Types and Properties of Ceramic Capacitors 2.4 Ceramic Capacitor  Classes Ⅲ Why Ceramic Capacitors Mostly Used in Electronic Circuit than Others? 3.1 Applications and Uses of Ceramic Capacitor 3.2  Properties or Advantages of Ceramic Capacitors Ⅳ How to Read Ceramic Capacitor? 4.1 Where to Use a Ceramic Capacitor? 4.2 How We Read Ceramic Capacitor Value？ 4.3 Calculate Ceramic Capacitor Value 4.4 Some Examples Ⅴ FAQ     Ⅱ Ceramic Capacitor Basics   2.1 What is a Ceramic Capacitor?   The capacitor value is unchangeable.  The working ceramic material acts as the dielectric, and it is a ceramic capacitor constructed of two or more alternating layers of ceramic and it has a metal layer acting as the electrodes, and the composition of the ceramic material defines the electrical behavior and thus applications.   As per below video of ceramic capacitors:     What is CERAMIC Capacitor _ Uses _ complete information in English     2.2 Ceramic Capacitor Polarity and Symbol   Ceramic capacitors are the most common type of capacitor found in all electrical devices, and they use a ceramic material as the dielectric. Ceramic capacitors are non-polarity devices, which means they have no polarities. As a result, we can connect it to a circuit board in any direction.   As a result, they are far safer than electrolytic capacitors. The symbol for a non-polarised capacitor is shown below. Many capacitors, such as tantalum beads, do not have polarity.     Ceramic Capacitor Polarity and Symbol       2.3 Types and Properties of Ceramic Capacitors   Ceramic capacitors come in three varieties, though other styles are available:   Resin-coated leaded disc ceramic capacitors for through-hole mounting.Multi-Layer Ceramic Capacitors with Surface Mount (MLCC).Microwave bare lead-free disc ceramic capacitors that are designed to fit into a PCB slot.   different types of ceramic capacitors     Ceramic disc capacitors   Ceramic disc capacitors are made by coating a ceramic disc on both sides with silver contacts. These devices can be made from multiple layers to achieve higher capacitances. Ceramic disc capacitors are typically through-hole components that are dwindling in popularity due to their size. If capacitance values allow, MLCCs are used instead. Ceramic disc capacitors have capacitance values ranging from 10pF to 100F and voltage ratings ranging from 16 volts to 15 kV and higher.   Multi-layer ceramic capacitor (MLCC)   MLCCs are fabricated by precisely combining finely ground granules of paraelectric and ferroelectric materials and then layering the mixture with metal contacts. Following the completion of the layering, the device is heated to a high temperature and the mixture is sintered, resulting in a ceramic material with the desired properties. The resulting capacitor is essentially made up of many smaller capacitors connected in parallel to increase the capacitance. MLCCs have 500 layers or more, with a minimum layer thickness of about 0.5 microns. As technology advances, layer thickness decreases, and higher capacitances for the same volume are achieved.     2.4 Ceramic Capacitor  Classes   Different ceramic capacitor classes are defined based on the working temperature range, temperature drift, and tolerance:   Class 1 Ceramic Capacitors   These are the most temperature-stable capacitors. They have nearly linear properties.The most commonly used dielectric compounds are.Magnesium Titanate is used to achieve a positive temperature coefficient.Calcium Titanate is used in capacitors that have a negative temperature coefficient.   Class 2 Ceramic Capacitors   Class 2 capacitors perform better at the price of volumetric efficiency, but at the expense of lower accuracy and stability. As a result, they are typically used for decoupling, coupling, and bypass applications where precision is not critical.Temperature range: -50 to +85 degrees CelsiusThe dissipation factor is 2.5 percent.Accuracy ranges from average to poor.   Class 3 Ceramic Capacitors   Class 3 ceramic capacitors have a high volumetric efficiency but a low dissipation factor. It is unable to withstand high voltages. Barium Titanate is a common dielectric.Temperature range of +10C to +55C will cause a -22% to +50% change in capacitance for a Class 3 capacitor.Dissipation factor: 3 to 5%.It will have a low level of accuracy (typically 20% or -20/+80%).   Class 3 is typically used for decoupling or in other power supply applications where accuracy is not critical.     Ⅲ Why Ceramic Capacitors Mostly Used in Electronic Circuit than Others?   Many circuits, particularly electronic circuits, use ceramic capacitors, as you may have noticed. Ceramic capacitors are largely used over electrolytic or other capacitors.   Ceramic capacitors     3.1 Applications and Uses of Ceramic Capacitor   In electronic sensor circuits, ceramic capacitors are used.Ceramic capacitors are used in the transmission and reception of electronic signals.Ceramic capacitors are applied in circuits such as audio mixers, controllers, and equalizers.Ceramic capacitors are suitable for frequency-dependent circuits, such as electronic filter circuits, audio circuits, radio signal transmitters, and receiver circuits. Resonant circuits, like radio frequency communication system, needs ceramic capacitors, too.Ceramic capacitors are used in alternating current circuits for no polarity such as high voltage protection circuits, power circuit breakers, and so on.Ceramic capacitors are used in direct current motors to reduce radio frequency noise.Ceramic capacitors can also be used as Bypass Capacitors.Why Ceramic Capacitors mostly used in Electronic Circuit?     3.2  Properties or Advantages of Ceramic Capacitors   Ceramic capacitors are available in extremely small sizes, which is a significant benefit. Because of the numerous electronic circuits, in fact, most modern electronic circuits necessitate the use of small size capacitors.   Many critical electronic circuits necessitate the use of very small capacitors. Ceramic capacitors are available in a wide range of sizes.   Ceramic capacitors can provide very high stability; in fact, they offer a wide range of stability.   Ceramic capacitors have a low temperature coefficient and a higher voltage breakdown characteristic.        5. Ceramic capacitors are the best choice for high-frequency applications.     Ⅳ How to Read Ceramic Capacitor?   Two reference tables   MarkingCapacitance (pF)Capacitance (ìF)101100 pF0.0001 ìF221220 pF0.00022 ìF471470 pF0.00047 ìF1021,000 pF0.001 ìF2222,200 pF0.0022 ìF4724,700 pF0.0047 ìF10310,000 pF0.01 ìF22322,000 pF0.022 ìF47347,000 pF0.047 ìF104100,000 pF0.1 ìF224220,000 pF0.22 ìF474470,000 pF0.47 ìF1051,000,000 pF1 ìF2252,200,000 pF2.2 ìF4754,700,000 pF4.7 ìF     Letter printed capacitor indicate tolerance LetterToleranceA±0.05 pFB±0.1 pFC±0.25 pFD±0.5 pFE±0.5%F±1%G±2%H±3%J±5 %K±10%L±15%M±20%N±30%P–0%, + 100%S–20%, + 50%W–0%, + 200%X–20%, + 40%Z–20%, + 80%     4.1 Where to Use a Ceramic Capacitor?   Ceramic capacitors are applied in a variety of applications. It is primarily used for filtration. It is used in a signal or frequency circuit to filter and purify the signal. It can convert a direct current to a direct current. The ceramic capacitor is a genre of energy storage device. It stores the DC while passing the AC. This is what the ceramic capacitor looks like.     4.2 How We Read Ceramic Capacitor Value？     alphabetic code     The first is an alphabetic code that indicates the component's tolerance. The second is a numeric code that tells us the actual capacitance of the capacitor.   So let's take a look at our example right now. In our example, the value is 102 k. The first significant digit in the code is one, and the second significant digit is zero. As a result, these are the numbers in front of our multiplier.         How to read the values of Ceramic Capacitors?   4.3 Calculate Ceramic Capacitor Value   So, if we take your multiplier, which is two, and looks at the chart, that equals two zeros. As a result, we append two zeros to the end of the number. So, picofarad, it's 1000. Now, K represents our component tolerance, which in this case is plus or minus 10%. So that's how we figure out the capacitor's size and rating.   Now I'm going to show you how to use a multimeter to measure the capacitance of a capacitor. In this example, I'm using a capacitor with the numerical value 103 written on it, which equals 10-nanofarads.       nine ferrites   When you look at the display of what is rated, you'll notice that its practical rating is it works, and it has nine ferrites. So tolerances are around 10%. When you connect it to your actual multimeter, In this one, make sure you have an appropriate terminal. As you can see, I have the capacitance symbol in the bottom right-hand corner. Then, make sure your multimeter is set to the appropriate range. Then double-check that you've selected the correct option.   Ceramic disk capacitor codes table   Picofarad pFNanofarad nFMicrofarad FCode100.010.00001100150.0150.000015150220.0220.000022220330.0330.000033330470.0470.0000474701000.10.00011011200.120.000121211300.130.000131311500.150.000151511800.180.000181812200.220.000222213300.330.000333314700.470.000474715600.560.000565616800.680.000686817500.750.000757518200.820.00082821100010.00110215001.50.0015152200020.00220222002.20.002222233003.30.003333247004.70.0047472500050.00550256005.60.005656210000100.110215000150.01515222000220.02222333000330.03333347000470.04747368000680.0686831000001000.11041500001500.151542000002000.22542200002200.222243300003300.333344700004700.474746800006800.68684100000010001105150000015001.5154200000020002205220000022002.2225330000033003.3335470000047004.7475   The final number written on a ceramic capacitor is the power of ten multiplied by the first two numbers. If a ceramic capacitor has the code 682, First, look at the last number. So, as we can see, the final number is 2. The multiplier is now 102.   4.4 Some Examples   204 = 20×104 = 200000 PF 472 = 47×102 = 4700 PF 502 = 50×102 = 5000 PF 330 = 33×100 = 33 PF   [100 = 1] UNITS   1000 nanofarad(nF) = 1 microfarad(µF) 1 picofarad = 10-12farads. Nano= 10-9 Micro= 10-6 1 Nano Farad= 10-9 Farad 1 Microfarad (µF)= 10-6 Farad 1 nF = 1000 pF 1 pF = 0.001 nF   Example:   convert 15 nF to pF: 15 nF = 15 × 1000 pF = 15000 pF   Capacitor voltage code   0G4VDC0L5.5VDC0J6.3VDC1A10VDC1C16VDC1E25VDC1H50VDC1J63VDC1K80VDC2A100VDC2Q110VDC2B125VDC2C160VDC2Z180VDC2D200VDC2P220VDC2E250VDC2F315VDC2V350VDC2G400VDC2W450VDC2H500VDC2J630VDC3A1000VDC   Ⅴ FAQ   1. What is ceramic capacitor used for? Ceramic capacitors are used for all types of circuits in a number of applications. There are four main capacitor applications that are described in detail below: coupling, decoupling, smoothing, and filtering.   2. Do ceramic capacitors go bad? Like mica capacitors, ceramic capacitors also very rarely go bad. Do not replace ceramic disc capacitors unless you are sure one has gone bad. ... While replacing the capacitors, check the radio's resistors. Since you will be replacing the capacitors, you should snip one lead of each paper and electrolytic capacitor.   3. Why do ceramic capacitors fail? Ceramic capacitors can fail in a couple of ways. They can be mechanically damaged - too much physical stress (pressure on the part or the board is bent a little too much) can cause a crack. The capacitor will then develop short circuits between layers. It acts more like a resistor in that case.  4. When should you use a capacitor? Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass. In analog filter networks, they smooth the output of power supplies. 5. What is the practical use of capacitor? The most common use for capacitors is energy storage. Additional uses include power conditioning, signal coupling or decoupling, electronic noise filtering, and remote sensing. Because of its varied applications, capacitors are used in a wide range of industries and have become a vital part of everyday life.  6. Why capacitor is not used as battery? Capacitors don't provide large amount of energy because they have less energy density than batteries. Capacitors are useful to provide short duration power requirements because they can be charged or discharged at a higher rate than the batteries. 

IntroductionPrinted Circuit Board(PCB) is a board of most modern electronic devices that has lines and pads that connect various points together. Even if it is a small board, its manufacturing process is very cumbersome and exquisite. Here will introduce the PCB manufacturing process steps by steps with pictures and video.How is PCB made?The following are the detailed PCB producing processes:IntroductionStep 1. PCB CAD FileStep 2. Plate ProductionStep 3. PCB Inner LayersStep 4. Board Punching and CheckingStep 5. LaminationStep 6. DrillStep 7. Copper Chemical Precipitation on the HolesStep 8. PCB Outer LayersStep 9. Computer Control and Copper ElectroplatingStep 1. PCB CAD FileThe first step in PCB production is to organize and check the PCB layout. The PCB manufacturers get the CAD files from the PCB design company, and they will convert them into a unified format-Extended Gerber RS-274X or Gerber X2, because each CAD software has its own unique file format. Then the electronic engineers will check whether the PCB layout conforms to the manufacturing process, and whether there are any defects and other issues.Figure 1. PCB CAD FileWhen making a PCB at home, the PCB layout can be printed on paper with a laser printer, and then transferred to the copper clad laminate. During the printing process, because the printer is prone to lack of ink and breakpoints, it is necessary to manually fill up the ink with an oil-based pen. Figure 2. PCB Laser PrintingHowever, the factory generally uses photocopying to print the PCB layout on the film. If it is a multi-layer PCB, the layout film photocopied on each layer will be arranged in order.Figure 3. PCB Film Arranged in OrderThen the film will be punched with alignment holes. Alignment holes are very important, which is essential to align the materials of each layer of the PCB.Step 2. Plate ProductionClean the copper plate. If there is dust, it may cause the final circuit to be short-circuited or broken.Figure 4. Clean the Copper PlateThe figure below is an example of an 8-layer PCB, which is actually made up of 3 copper clad laminates plus 2 copper films, and then glued them together with prepregs. The production sequence is to start with the middle board (4th- and 5th-layer of circuits), continuously stack together, and then fix. The production of 4-layer PCB is similar, including one core board and two copper films.Figure 5. 8-layer PCB Plate DisplayStep 3. PCB Inner LayersFirst, make the two-layer circuit of the middle core board. After the copper clad laminate is cleaned, it will be covered with a photosensitive film on the surface. This film will solidify when exposed to light, forming a protective film on the copper foil.Figure 6. PCB CoreInsert the two-layer PCB layout film and the double-layer copper clad laminate into the upper PCB layout film to ensure that the upper and lower PCB layout films are stacked accurately.Figure 7. PCB Layout Film PlacingThe machine irradiates the photosensitive film on the copper foil with a UV lamp. The transparent film is cured under the light, and there is still no cured photosensitive film. The copper foil covered under the cured film is the required PCB layout, which is equivalent to the function of the laser printer ink of the manual PCB. In addition, the copper foil covered by the black film will be corroded away, and the cured transparent film will be preserved.Figure 8. Cured Photosensitive FilmClean the uncured photosensitive film with lye, and the required copper foil circuit will be covered by the cured film.Figure 9. Clean Uncured Photosensitive FilmThen use a strong base, such as NaOH, to etch away the unnecessary copper foil.Figure 10. Copper Foil EtchingTear off the cured photosensitive film to expose the copper foil of the required PCB layout.Figure 11. Tear Off the Cured Photosensitive FilmStep 4. Board Punching and CheckingThe core board has been successfully produced. Then punch alignment holes on it to facilitate with other materials.Figure 12. Punch Alignment Holes on PCBOnce the core board is pressed together with other layers, it cannot be modified. So PCB checking is very important. The machine will automatically compare with the PCB layout drawing to find out the error.Figure 13. PCB Layout Drawing ComparisonThe first two layers of PCB boards have been made.Step 5. LaminationA new raw material is introduced here called Prepreg, which is the adhesive among the core boards(PCB layers>4), as well as the core board and the outer copper foil, and it also plays a role in insulation.Figure 14. PCB Prepreg and CopperThe lower copper foil and the two layers of prepreg have been fixed in advance through the alignment hole and the lower iron plate, and then the finished core board is also placed in the alignment hole, and finally the two layers of prepreg, a layer of copper foil and a layer of pressure-bearing aluminum plate covers the core plate.Figure 15. Fixed PCB Prepreg and CopperIn order to improve work efficiency, this factory will stack three different PCB boards together before fixing them. The upper iron plate is magnetically attracted to facilitate alignment with the lower iron plate. After the two layers of iron plates are successfully aligned by inserting the alignment pins, the machine compresses the space between the iron plates as much as possible, and then fixes them with nails.Figure 16. Fixed PCB LayersThe PCB boards clamped by the iron plates are placed on the holder, and then sent to the vacuum heat press for laminating. The high temperature can melt the epoxy resin in the prepreg and fix the core boards and copper foils together under pressure.Figure 17. PCB Layers LaminationAfter the lamination, remove the upper iron plate that presses the PCB. Then remove the pressure-bearing aluminum plate. The aluminum plate also plays the role of isolating different PCBs and ensuring the smoothness of the outer copper foil of the PCB. Finally the PCB taken out at this time will be covered by a layer of smooth copper foil.Figure 18. Remove the Upper Iron Plate and Aluminum PlateStep 6. DrillSo how to connect 4 layers of copper foils that are not in contact with each other in the PCB? First, make the through-hole through the PCB, and then metalize the hole wall to conduct electricity.Figure 19. PCB DrillPut a layer of aluminum plate on the punching machine, and then put the PCB on it. Since drilling is a relatively slow process, in order to improve efficiency, according to the number of layers of the PCB, 1 to 3 identical boards are stacked for drilling together. Finally, cover the uppermost PCB with a layer of aluminum plate. The upper and lower of aluminum plates are used to prevent the copper foil on the PCB from tearing when drilling.Figure 20. PCB DrillNext, you only need to select the correct drilling program on the computer, and the rest is done automatically by the drilling machine. The drill bit is driven by air pressure, and the maximum rotation speed can reach 150,000 revolutions per minute. Because such a high rotation speed is sufficient to ensure the smoothness of the hole wall.Figure 21. Drill ProgramThe replacement of the drill bit is also automatically completed by the machine according to the program. The smallest drill bit can reach a diameter of 100 microns, while the diameter of a human hair is 150 microns.Figure 22. Drill ReplaceIn the previous process, the molten epoxy was squeezed out of the PCB, so it needed to be cut off. Here the profiling milling machine cuts its periphery according to the correct XY coordinates of the PCB.Figure 23. Cuts PCB PeripheryStep 7. Copper Chemical Precipitation on the HolesSince almost all PCB designs use perforations to connect different layers of lines, a good connection requires a 25-micron copper film on the hole wall. The thickness of the copper film needs to be realized by electroplating, but the hole wall is composed of non-conductive epoxy resin and glass fiber board. So the first step is to deposit a layer of conductive material on the hole wall, and form a 1 micron copper film on the entire PCB surface by chemical deposition. The entire process such as chemical treatment and cleaning is controlled by the machine.Step 8. PCB Outer LayersNext, the PCB outer layer is transferred to the copper foil. The process is similar to the transfer principle of the previous PCB inner core board. The PCB layout is transferred to the copper foil by photocopying film and photosensitive film. The only difference is positive films will be used as boards.The transfer of the internal PCB layout described above uses the subtractive method, and the negative film is used as the board. The PCB is covered by the cured photosensitive film as a circuit, and the uncured film is cleaned. After the exposed copper foil is etched, the PCB layout circuit is protected by the cured film. The transfer of the outer PCB layout adopts the normal method, and the positive film is used as the board. The non-circuit area is covered by the cured photosensitive film on the PCB. After cleaning the uncured film, electroplating is performed. Where there is a film, it cannot be electroplated, and where there is no film, copper is plated first and then tin is plated. After the film is removed, alkaline etching is performed, and finally the tin is removed. So the circuit pattern remains on the board because it is protected by tin.Put the cleaned PCB on both sides of the copper foil into the laminating machine, and the photosensitive mold will be pressed onto the copper foil.Figure 24. LaminatorFix the printed PCB layout film of the upper and lower layers through the holes, and put the PCB board in the middle. Then, the photosensitive film under the light-transmitting film is cured by the irradiation of the UV lamp, which is the circuit that needs to be reserved.Figure 25. PCB Expose to the UV LightAfter cleaning off the unnecessary and uncured photosensitive film, inspect the PCB board.Figure 26. PCB CheckingClamp the PCB with clips, and electroplate the copper. As mentioned earlier, in order to ensure that the holes have sufficient conductivity, the copper film plated on the hole walls must have a thickness of 25 microns, so the entire system will be automatically controlled by the computer to ensure its accuracy.Figure 27. PCB Copper PlatingStep 9. Computer Control and Copper ElectroplatingAfter the copper film is electroplated, the computer gives instructions to electroplate a thin layer of tin. Then, check to ensure that the thickness of the plated copper and tin is correct.Figure 28. Electroplated Copper and Tin InspectionNext, a complete automated assembly line completes the etching process. Then, clean the cured photosensitive film on the PCB.Figure 29. Clean Cured Photosensitive FilmThen use a strong alkali to clean the unnecessary copper foil covered by it.Figure 30. Clean the Unnecessary Copper FoilFinally, use the tin stripping solution to strip the tin plating on the PCB layout copper foil. After cleaning, the 4-layer PCB layout is complete. Frequently Asked Questions about PCB Manufacturing Process1. Which are the techniques of PCB manufacturing?There are several PCB manufacturing methods that a PCB can be submitted to before reaching the final product. These methods include preparing the board's surface, placing components, soldering, cleaning, and inspection and testing. 2. What is PCB design process?Step 1 – The DesignStep 2 – Printing the DesignStep 3 – Creating the SubstrateStep 4 – Printing the Inner LayersStep 5 – Ultraviolet LightStep 6 – Removing Unwanted CopperStep 7 – Inspection.Step 8 – Laminating the Layers 3. Which software is best for PCB design?Top 8 Best PCB Design Software of 2021PROTEL (Altium Designer)PADS (PowerPCB)ORCADAllegroEagle (Easily Applicable Graphical Layout Editor)KicadEasyEdaFritzing 4. What is a PCB layer?A PCB is defined as a number of copper layers in a well defined sequence. Copper layers of a PCB are usually just named layers or also called SIGNAL layer. However, to define the complete PCB, other layers are required. They are usually named by their functionality and position. 5. What are the components of a PCB?Some common PCB components include:Battery: provides the voltage to the circuit.Resistors: control the electric current as it passes through them. They’re colour coded to determine their value.LEDs: light emitting diode. Lights up when current flows through it, and will only allow current to flow in one direction.Transistor: amplifies charge.Capacitators: these are components which can harbour electrical charge.Inductor: stores charge and stops and change in current.Diode: allows current to pass in one direction only, blocking the other.Switches: can either allow current or block depending if they are closed or open.

 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.   

What is Breadboard?When learning how to build a circuit, the breadboard is one of the most basic parts. There are many small jacks on the breadboard, which are specially designed and manufactured for solderless experiments of electronic circuits. A breadboard consists of plastic block holding a matrix of electrical sockets of a size suitable for gripping thin connecting wire, component wires or the pins of transistors and integrated circuits (ICs). The sockets are connected inside the board, usually in rows of five sockets. Since various electronic components can be inserted or pulled out at will according to needs, welding is eliminated, circuit assembly time is saved, and components can be reused, so it is very suitable for the assembly, debugging and training of electronic circuits.What is Breadboard?Topics Covered in this GuideWhat is Breadboard?Why are breadboards called breadboards?How Breadboard Looks like?IC & DIPHow to Use Breadboards?Types of BreadboardsBasic Principles of Breadboard WiringBreadboard Using Tips for BeginnersMaintenance of the BreadboardsWhich Breadboard is Best?What are the Holes in the Breadboard Called?Is a Breadboard Necessary?How much Voltage can a Breadboard Handle?How Does Current Flow in a Breadboard?How Many Amps Can a Breadboard Take?Why are breadboards called breadboards?The name of the breadboard can be traced back to the era of vacuum tube circuits. At that time, most of the circuit components were large in size. People usually fixed them on a wooden board for cutting bread with screws and nails for connection. Later, the circuit components became more and more smaller, but the name of the breadboard is still used. The breadboard most commonly used today is usually made of white plastic and is a pluggable (solderless) breadboard. It was designed by Ronald J. Portugal in 1971.It is a process of verifying ideas by creating an initial model. If you are not sure how a circuit will react normally under a given parameter setting, it is best to build a prototype to test it. For those who are new to electronic circuits, the breadboard is a good start. The advantage of a breadboard is that it can hold the simplest and most complex circuits at the same time. If your circuit cannot be accommodated by the current breadboard, you can splice other boards to adapt to all circuits of different sizes and complexity. Such as integrated circuits (ICs). When you try to master how a module works and need to rewire multiple times, you certainly don't want to solder the circuit interface every time. Once you find a problem, you can disassemble each part to prepare for some troubleshooting. How Breadboard Looks like?The shape of the breadboard is mostly cuboid, with different sizes. The breadboard generally has two layers, the top is a grid shape with double-sided tape adhering to it( you can tore it to fix the breadboard in a certain position). The upper layer of the breadboard is composed of a grid of rows and columns, and there is no conduction between rows.The whole board is made of thermosetting phenolic resin, and there are metal strips at the bottom of the board. Holes are punched at the corresponding positions on the board so that the components can be in contact with the metal strips when inserted into the board, so as to achieve the purpose of conducting electricity. Generally, every 5 orifice plates are connected by a metal strip. There are two rows of vertical jacks on both sides of the board, also a group of 5. These two sets of jacks are used to provide power to the components on the board.Breadboard Layout ExampleSome breadboards have two columns on the left and right sides. These two columns are customarily used as the positive and negative poles of the power supply (This is not necessarily true, depending on your own usage habits and circuit needs). Each of the five grids in the same column of the two columns is a group, which is conductive. But there is no conduction between columns. Then in the middle part, every five columns of grids form a group, and the five grids in this group are conductive. There is generally a groove in the center of the board, which is designed for the needs of integrated circuit (IC) and chip testing, and is used to separate the left and right parts of a board. Some breadboards do not have two columns on the left and right sides due to the size, but the other structures are the same.The motherboard uses a glass fiber board with a conductive layer of copper foil, which is used to fix the solderless breadboard and lead out the power terminal.There may be slight differences in the structure between different breadboards, but they are basically the same. IC & DIPAn unique feature of the breadboard is: Integrated Circuit (IC) and Dual in-line Package (DIP)Dual in-line Package (DIP) Chip：MA2053Do you see the small gap in the middle of the breadboard? There is a reason for this gap, the use of integrated circuits. There are ICs in almost every electronic device. They run motors, regulate voltage, act as timers, perform logic tasks, and perform almost everything you need to perform.ICs can have different numbers of pins, sizes and functions. However, many ICs are suitable for a standard called dual in-line packaging (DIP), which means they all share a set width. As you guessed, the width fits the gap in the middle of the breadboard. This makes it easier to use the IC without having to worry about connecting the wrong pins together. the holes of the breadboard are spaced 0.1” (2.54mm) apart in both the X and Y direction which is the spacing used for adjacent DIP IC leads as well as many other components such as headers.IC & DIP Example on Breadboard How to Use Breadboards?You can use breadboard to make quick electrical connections between components- like resistors, LEDs, capacitors, etc, so that you can test your circuit before permanently soldering it together. Without welding and manual wiring, the circuit and components can be tested by inserting the component into the hole, which is convenient to use. Before use, determine which component's pins should be connected together, and then insert them into the same group of 5 small holes.How to Use a Breadboard?Example: LED Lighting1) MaterialsOne breadboard, several connecting wires (the connecting wires should use needle-shaped wires at both ends), one led light, and one 3V button battery.2) First, put the battery into the battery holder (this can be bought online), and plug it into the breadboard. Then, insert the battery holder into the left and right parts of the breadboard. Parts are separated by grooves to avoid short circuit between the positive and negative poles of the power supply).3) Lead two wires from the positive and negative poles of the battery, and then plug the LED into any two grids that are not conductive on the breadboard (the long pin of the led is positive and the short pin is negative), and finally connect the wires from the positive and negative poles of the battery to the two LED segments.Types of Breadboards1) Solderless BreadboardA solderless breadboard is a motherboard that does not serve as a base, and does not have a soldering power socket to draw out but can expand a single breadboard. Connect the two poles of the power supply to the sockets on both sides of the breadboard, and then you can plug in the components for experiment (the power supply should be disconnected during the process of inserting the components). When more than 5 components or a set of jacks cannot be inserted, you need to connect multiple sets of jacks with a breadboard cable.The advantages of solderless breadboards are small size and easy to carry, but the disadvantages are relatively simple, inconvenient power connection, and small area. It is not suitable for large-scale circuit experiments. If you want to use it for large-scale circuit experiments, you need to fix multiple breadboards on a large wooden board with screws, and then connect them with wires.2) Single BreadboardA single breadboard is a part with a motherboard as a base and a dedicated terminal for power access, and even some breadboards that can perform high-voltage experiments include ground terminals. This kind of board is more convenient to use, that is, directly connect the power supply to the terminal, and then insert the components for experiment (the power supply should be disconnected during the process of inserting the components) when more than 5 components or a set of jacks cannot be inserted, you need to use breadboard cables to connect multiple sets of jacks.The advantage of a single breadboard is that it is small in size, easy to carry, and can easily switch on and off the power supply, but it has a small area and is not suitable for large-scale circuit experiments.3) Composite breadboardComposite breadboard is a board composed of many solderless breadboards. Generally, 2-4 solderless breadboards are fixed on the motherboard, and then the power cords of each board are connected together with the copper foil in the motherboard. The kind of breadboards is also specially designed for different circuit units to control the power supply, so that each board can carry different voltages according to the needs. The use of the composite breadboard is the same as the single breadboard.The advantage of the composite breadboard is that it can conveniently switch on and off the power supply, has a large area to carry out large-scale experiments, and is highly mobile, and has a wide range of uses. However, it is large and heavy for carrying, so it is suitable for laboratories and electronic hobbyists use. Basic Principles of Breadboard WiringComplete the circuit overlap on the breadboard, different people have different styles. However, no matter what style or habit, the following basic principles must be paid attention to when completing the circuit overlap:1. The fewer connection points, the better.Each additional connection point actually increases the probability of failure artificially. There are common faults such as impassability in the breadboard hole, loose wire, and broken wire inside.2. Try to avoid overpasses.The so-called "overpass" means that components or wires ride on other components or wires. Beginner is easy to make such mistakes. It will bring trouble to the replacement of components in the later stage. On the other hand, in the event of a failure, the messy wires can easily make people lose confidence.3. Try to be as reliable as possible.There are two phenomena that need attention:① Breadboard integrated circuits are easy to loosen. Therefore, for integrated circuits such as operational amplifiers, it is necessary to press down forcefully. Once it is not reliable, the position needs to be changed.② The pins of some components on the breadboard are too thin, so please be careful to move them slightly. If you find that they are not secure, you need to change the position.Electronic BreadboardBreadboard Using Tips for Beginners1. When installing discrete components, it should be easy to see their polarity and signs. After placing the component pins, bend them where needed. In order to prevent the exposed leads from short-circuiting, a wire with a sleeve must be used, and the component pins are generally not cut to facilitate repeated use. Generally, do not insert components with a pin diameter> 0.8mm, so as not to damage the elasticity of the contact piece inside the socket.2. The pins of integrated circuits that have been used many times must be repaired neatly, the pins cannot be bent, and all the pins should be slightly skewed outward, so that the lead angles and the jacks can be reliably contacted. The arrangement of the components on the breadboard should be determined according to the circuit diagram in order to facilitate the wiring. In order to be able to correctly route and facilitate wire checking, the insertion direction of all ICs must be kept the same, and which cannot be inserted upside down for the convenience of temporary wiring or to shorten the length of the wire.3. According to the sequence of the signal flow, the method of installation and debugging is adopted. After the components are installed, first connect the power cord and the ground wire. In order to check the line conveniently, try to use different colors for the line. For example, the positive power supply generally uses a red wire, the negative power supply uses the blue, the ground wire uses the black, and the signal wire uses the yellow. Other colors can also be selected according to the real conditions.4. The breadboard should use a single-strand wire with a diameter of about 0.6mm. Cut the wire according to the distance of the wire and the length of the jack. The wire end is required to be cut into a 45º, and the stripped length of the wire end is about 6mm. All the wires are required to be inserted into the bottom plate to ensure good contact. In addition, bare wires should not be exposed to prevent disconnection with other wires.5. The connection is required to be tightly attached to the breadboard to avoid collision and ejection of the breadboard, resulting in poor contact. The wiring must pass around the integrated circuit, and it is not allowed to cross the integrated circuit, and the wires must not be overlapped with each other, try to be horizontal and vertical. This is conducive to line wiring and checking, and components replacement.6. It is best to connect a capacitor with a capacity of tens of microfarads in parallel between the input terminal of each power supply and the ground, so as to reduce the impact of current during transients. In order to suppress the high-frequency components in the power supply, a high-frequency decoupling capacitor should be connected in parallel at both ends of the capacitor, generally 0.01~0.047Uf.7. During the wiring process, it is required to place the various components on the corresponding position on the breadboard and mark the pin numbers used on the circuit diagram to ensure the smooth progress of debugging and troubleshooting.8. All ground wires must be connected together to form a common reference point. Maintenance of the BreadboardsUsing a breadboard is more convenient than using a soldering method, easy to replace wires and components, and can be used multiple times. However, the breadboard should be maintained during daily use. In the multiple use of the breadboard, the spring sheet will become loose and the elasticity will become poor, which is easy to cause poor contact and virtual welding. They are difficult to find out.The breadboard that has been used many times should be uncovered from the back, and the spring sheet with poor elasticity should be taken out, repaired and then inserted into the original position. This can enhance the elasticity and increase the reliability and service life of the breadboard. In addition, pay attention to where the breadboard is used. Large-volume, high-quality or high-power components cannot be plugged into the breadboard because the breadboard jacks are small and the leads of such large components are relatively thick. At this time, the components can only be placed outside the board. Use a single strand of hard wire to solder to the lead, and then insert it into the breadboard.Breadboards are not suitable for high-frequency circuits, because the lead inductance and distributed capacitance of the breadboard are relatively large, which has a great impact on the performance of high-frequency circuits. Breadboard is suitable for integrated circuits, especially for digital integrated circuits, because digital integrated circuits usually have low operating frequency and low power, and they use fewer RC components. It is more difficult for discrete component circuits to use breadboards, especially for circuits with high frequency and high power. Which Breadboard is Best?Best Breadboard Kit ReviewsELEGOO Upgraded Electronics Fun KitREXQualis Electronics Component Fun KitElegoo EL-CP-003 3 MB-102 830-pin solderless PCB board kitFreenove Solderless Breadboard Ultimate Starter KitKeywishbot Electronic Component BreadboardREXQualis Solderless BreadboardKuman GPIO expansion kit for Raspberry PieBoot 3 400-point solderless circuit breadboardPaxcoo 4 breadboard kits with 120 jumper wires for ArduinoSmraza Basic Starter KitSunFounder breadboard kit RAB holderTEKTRUM Solderless plug-in breadboard kitMicrotivity IB401 400-point experiment breadboardElenco 9440 breadboard with 350 jumper wire set kitMakeronics Breadboard + Electronics Fun Kit What are the Holes in the Breadboard Called?Breadboards are designed to work with through-hole electronic components. They have many tiny sockets (called 'holes') arranged on a 0.1" grid. The leads of most components can be pushed straight into the holes. ICs are inserted across the central gap with their notch or dot to the left.The holes in the top-most rail are highlighted in orange and the holes in the bottom-most one are highlighted in green. In the central area of the board are vertical lines of five holes that are electrically connected. These lines of five holes are known as nodes. Is a Breadboard Necessary?Although a breadboard is essential to prototype circuits without having to solder them together and when you have verified that the circuits works you can solder it onto a perfboard. But note that breadboards are never necessary. A properly-milled and constructed panel should generally stay flat under normal conditions, so the only time I add a breadboard end is if I think the design benefits from it visually.In addition, high frequency (above 10MHz) Where the additional breadboard capacitance would present problems (oscillators, etc) Where glitches due to poor wire connections would result in poor operation. Where most of the parts are not through hole 0.1" (2.54mm) centers. How much Voltage can a Breadboard Handle?Breadboards are mostly used for low voltage and current applications, however, breadboards can handle 12 volts. Breadboards are made by different manufacturers, so the voltages they can handle depends on how they are constructed. How Does Current Flow in a Breadboard?The vertical columns of the breadboard are called terminals, while the horizontal long rows are called power rails because they are mostly used to connect the power supply to the breadboard. The positive rails are indicated by red lines, while the negative rails are indicated by black ones. That means our electric current, which is made up of moving charges, flows out of the positive side of the battery, through the wire and into the breadboard power bus. It then flows out of the black wire and into the second power bus, through the power bus and back to the negative side of the battery. How Many Amps Can a Breadboard Take?Due to the temporary nature of the contacts, most breadboard has a current limit of one amp or less. Breadboard generally cannot handle frequencies greater than ten megahertz because of the nature of the contacts, which create a stray capacitance of around two to twenty picofarads (pFs) for every connection.

IntroductionFLASH is a type of non-volatile memory that retains data even when power is disconnected. Unlike RAM, which can rewrite data at the byte level, flash memory operates differently. A flash memory chip consists of an array of data storage cells organized into blocks, with each block containing multiple pages (typically 64 to 256 pages in modern devices, though older devices used 32 pages). A page is usually 2KB, 4KB, 8KB, or 16KB in modern NAND flash, though the original specification was 512 bytes plus spare area, as flash was initially developed as a disk replacement technology.What Is Flash Memory?Ⅰ Types of Flash MemoryFlash memory is widely used as a storage medium in digital cameras, smartphones, tablets, USB drives, SSDs, and various consumer electronics. Flash memory cards come in various form factors depending on manufacturers and applications, including USB flash drives, CompactFlash (CF card), MultiMediaCard (MMC card), Secure Digital (SD card, microSD), Memory Stick, and XD-Picture Card (XD card). Note that SmartMedia (SM card) and Microdrive have been discontinued. While these flash cards have different physical formats and specifications, their underlying technical principles remain similar.Flash memory includes two main architectural types: NOR Flash and NAND Flash. NOR Flash is a random access device with dedicated address and data lines (similar to SRAM), allowing byte-level read and write operations and direct access to any memory location, making it an excellent ROM alternative, such as in computer BIOS chips. NAND Flash, however, lacks dedicated address lines and cannot be directly addressed. It is controlled by sending commands and addresses through an I/O interface, meaning NAND Flash can only be accessed in pages, making it more suitable for sequential data storage.Ⅱ NAND Flash MemoryNAND Flash is extensively used in high-capacity storage devices such as memory cards, USB drives, SSDs, eMMC, and UFS storage. NAND Flash cells are categorized by the number of bits stored per cell: SLC (Single-Level Cell), MLC (Multi-Level Cell), TLC (Triple-Level Cell), and QLC (Quad-Level Cell). SLC stores 1 bit per cell, MLC stores 2 bits, TLC stores 3 bits, and QLC stores 4 bits per cell.As more bits are stored in a single cell, the read/write performance decreases, endurance diminishes, but cost per gigabyte is reduced, making higher-density options more economical for consumer applications.ItemsSLCMLCTLCQLCBits Per Cell1234P/E Cycles50,000-100,0003,000-10,0001,000-3,000100-1,000Read Time (μs)255075100Program Time (μs)200-300600-900900-13501350-2000Erase Time (ms)1.5-234.56-8SLC is primarily used in enterprise, industrial, and military applications due to its high-speed writing, low error rate, and exceptional durability.MLC is targeted at consumer and prosumer applications, offering twice the capacity of SLC at lower cost. It's suitable for USB drives, smartphones, digital cameras, and consumer-grade SSDs.TLC has become the mainstream choice for consumer SSDs and SD cards due to its balance of cost, capacity, and acceptable performance for everyday use.QLC, introduced more recently, offers even higher density and lower cost per gigabyte, making it increasingly popular in budget SSDs and high-capacity storage solutions, though with reduced endurance.As a practical solid-state storage medium, NAND Flash has unique physical characteristics requiring specialized management. Designers face several key challenges:1) Erase-before-write requirement: Data cannot be overwritten directly; blocks must be erased before new data can be written2) Wear mechanism: Limited program/erase (P/E) cycles impose durability constraints3) Read/write interference: Operations can cause data errors in adjacent cells4) Data retention: Charge leakage over time can cause data loss5) Bad block management: Both factory defects and runtime failures must be managedKey technologies addressing these challenges include:1) Cell type selection: Choosing appropriate NAND type (SLC/MLC/TLC/QLC) based on application requirements2) Wear leveling algorithms: Distributing write operations evenly across all blocks to maximize lifespan3) Bad block management: Identifying and mapping out defective blocks to ensure data integrity4) Error Correction Code (ECC): Detecting and correcting bit errors using advanced algorithms like BCH or LDPC5) Write amplification mitigation: Minimizing unnecessary write operations to extend device life6) Garbage collection: Consolidating valid data and reclaiming space from partially used blocksData is stored as electrical charge in Flash memory cells. The amount of stored charge depends on the voltage applied to the Control Gate, which controls whether charge is injected or removed from the floating gate.1) For programming (writing) NAND Flash, voltage is applied to the Control Gate to inject electrons into the floating gate. When charge exceeds the threshold voltage (Vth), the cell represents a logical 0.2) For erasing NAND Flash, electrons are removed from the floating gate. When charge falls below the threshold voltage (Vth), the cell represents a logical 1. Ⅲ NOR Flash MemoryNOR Flash, similar to conventional memory, supports random access, enabling XIP (eXecute In Place) functionality. This allows code execution directly from the flash without copying to RAM, making it ideal for boot code, BIOS/UEFI firmware, and embedded system applications requiring immediate code execution.NOR Flash is categorized into two types based on host interface: Parallel NOR Flash and Serial NOR Flash.Parallel NOR Flash connects directly to the host controller with its contents mapped into the CPU address space, eliminating the need to copy to RAM. Early BIOS implementations used the FWH (Firmware Hub) interface, a parallel connection that has been largely obsoleted due to pin count and speed limitations.Serial NOR Flash is more cost-effective than Parallel NOR Flash and typically connects to the host processor or Platform Controller Hub (PCH) via SPI (Serial Peripheral Interface), Quad-SPI (QSPI), or Octal-SPI interfaces. Modern implementations support higher speeds through multi-lane configurations.Today, virtually all UEFI/BIOS firmware, embedded systems, IoT devices, and many consumer electronics use NOR Flash. Typical capacities range from 1MB to 256MB, with 16MB-128MB being common for modern UEFI implementations. While more expensive per gigabyte than NAND, NOR Flash offers superior reliability and random access performance.NOR Flash has slower erase speeds and lower erase cycle counts compared to NAND, but these limitations rarely impact BIOS/firmware performance or cause device failures due to the infrequent update nature of firmware. Ⅳ NAND Flash vs NOR FlashCompared with NOR flash memory, NAND flash memory requires fewer transistors per cell to store the same amount of data, resulting in smaller die size and higher storage density. This architectural difference makes NAND significantly more cost-effective for high-capacity storage applications.In terms of read speed, NOR flash memory offers faster random access than NAND flash memory, with typical access times of 50-100ns compared to NAND's page-based access. However, NAND flash memory significantly outperforms NOR in sequential write and erase operations. NAND's block-based erase operation is simpler and faster, erasing entire blocks (typically 128KB-4MB) at once.NOR flash memory requires all bits to be set to 1 during erase operations before programming. While NOR flash memory provides faster random access and simpler byte-level operations, its lower storage density and higher cost make it more suitable for code storage and execution. NAND flash memory provides extremely high cell density (modern single chips can exceed 1TB capacity), making it ideal for mass data storage with fast write and erase speeds. Additionally, NAND flash operates on page-based read/write units (typically 4KB-16KB) and block-based erase units, making it functionally similar to traditional disk drives.NAND Flash is more susceptible to bit errors than NOR Flash, necessitating robust Error Detection and Correction (EDC/ECC) algorithms. Modern NAND implementations use advanced ECC schemes like BCH (Bose-Chaudhuri-Hocquenghem) or LDPC (Low-Density Parity-Check) codes. Additionally, NAND Flash develops bad blocks over its lifetime. File systems like FAT on SD cards experience frequent rewrites of the file allocation table, and the P/E cycle count per block is critical to NAND Flash longevity. Balancing erase cycles across all blocks and managing bad blocks requires specialized firmware-level functionality including bad block management, wear leveling, ECC, and garbage collection. This management layer is called the FTL (Flash Translation Layer). Based on FTL implementation location, Flash Memory is categorized as Raw Flash or Managed Flash.Raw Flash requires the host system to implement FTL functionality, giving designers complete control but requiring significant software development. Managed Flash (such as eMMC, UFS, SD cards) includes an integrated controller that handles FTL operations transparently, simplifying host system design at the cost of reduced low-level control.Ⅴ Universal Flash Storage Versions ComparisonStorage performance significantly impacts device responsiveness and user experience. Universal Flash Storage (UFS) has become the dominant standard for high-performance mobile and embedded storage, replacing the older eMMC standard. UFS provides a standardized flash storage specification optimized for smartphones, tablets, automotive systems, and other performance-critical applications. Version numbers indicate generational improvements, with higher versions offering substantially better performance, features, and efficiency.✔️Version Comparison (Main Parameters)UFS Version1.01.12.02.13.03.14.0Introduced2011-02-242012-06-252013-09-182016-04-042018-01-302020-01-302023-09-14Bandwidth per lane300 MB/s600 MB/s1450 MB/s (HS-G3)2900 MB/s (HS-G4)5800 MB/s (HS-G5)Max. number of lanes12Max. total bandwidth300 MB/s1200 MB/s2900 MB/s (HS-G3)5800 MB/s (HS-G4)11600 MB/s (HS-G5)M-PHY version1.03.04.15.0UniPro version1.41.61.82.0✔️UFS 2.1 vs UFS 2.2The primary enhancement in UFS 2.2 over UFS 2.1 is the Write Booster feature, which significantly improves write performance. Write Booster uses SLC (Single-Level Cell) cache to accelerate write operations, providing faster application launches, improved browser cache loading, reduced video encoding times, and enhanced overall system responsiveness. This feature is particularly beneficial for burst write scenarios common in mobile devices.As eMMC has been phased out from mainstream consumer devices and NAND flash prices have decreased, UFS adoption has accelerated. UFS 2.2 briefly served as a transitional standard before UFS 3.x became mainstream in flagship devices.✔️UFS 3.0 vs UFS 3.1UFS 3.1 introduces three significant enhancements over UFS 3.0:1) Write Booster (Enhanced)Write Booster in UFS 3.1 is an enhanced version that increases device write speed substantially. This feature can boost write speeds up to 700 MB/s, compared to UFS 3.0's typical sequential write performance of around 500 MB/s. The mechanism works similarly to SLC caching in SSDs: a portion of TLC/QLC storage is dynamically configured to operate in SLC mode, providing faster write performance. Data is initially written to this high-performance buffer, then migrated to standard storage during idle periods, freeing the cache for subsequent operations.2) Deep Sleep ModeDeep Sleep enables the flash memory to enter an ultra-low-power state during extended idle periods, significantly reducing standby power consumption. This feature helps extend battery life during device standby and contributes to overall device thermal management. Deep Sleep can reduce idle power consumption by up to 40% compared to standard sleep modes.3) Host Performance Booster (HPB)HPB addresses long-term performance degradation by improving random read performance. As devices are used over time, file system fragmentation and the need to frequently reload the Logical-to-Physical (L2P) mapping table can cause performance degradation. HPB leverages the host device's RAM to cache portions of the L2P mapping table, reducing latency for random read operations. This is particularly effective at maintaining consistent performance after extended use, preventing the "slowdown over time" phenomenon common in storage devices. HPB can improve random read IOPS by up to 70% in fragmented scenarios.✔️UFS 4.0 - The Latest GenerationReleased in September 2023, UFS 4.0 represents the latest advancement in mobile storage technology. Key improvements include:• Doubled bandwidth: Up to 11.6 GB/s (5800 MB/s per lane with dual-lane configuration) using HS-G5 gear• Improved power efficiency: Lower power consumption per bit transferred compared to UFS 3.1• Enhanced thermal management: Better heat dissipation characteristics for sustained performance• Advanced features: Builds upon Write Booster, Deep Sleep, and HPB with further optimizationsUFS 4.0 is designed for next-generation flagship smartphones, tablets, and high-performance mobile devices requiring extreme storage bandwidth for 8K video recording, advanced computational photography, and AI workloads. Frequently Asked Questions about Flash Memory1. What are the different types of flash memory?Flash memory comes in two fundamental architectural types: NOR and NAND. NOR flash offers random access and execute-in-place capabilities, making it ideal for code storage. NAND flash provides higher density and faster write speeds, making it suitable for data storage. Within NAND flash, there are further subdivisions based on bits per cell: SLC (1 bit), MLC (2 bits), TLC (3 bits), and QLC (4 bits), each offering different trade-offs between performance, endurance, and cost. 2. What are the characteristics of flash memory?Flash memory has several distinctive characteristics: it is significantly less expensive than EEPROM and doesn't require batteries for data retention unlike SRAM. It is non-volatile, meaning data persists without power. Flash offers fast read access times (microseconds), high resistance to physical shock compared to hard disk drives, low power consumption, and silent operation. However, it has limitations including finite write/erase cycles, block-level erase requirements, and potential for bit errors requiring ECC. 3. What is the purpose of flash memory?Flash memory serves as a non-volatile storage solution widely used in embedded systems, consumer electronics, and enterprise storage. It retains data without power, can be electrically erased and reprogrammed, and offers advantages over traditional magnetic storage including faster access times, lower power consumption, better durability, and compact form factors. Flash memory evolved from EEPROM technology and has become the dominant storage technology for mobile devices, SSDs, USB drives, memory cards, and embedded systems. 4. What is the difference between NAND flash and NOR flash?NOR flash provides faster random read access and supports execute-in-place (XIP), allowing direct code execution without copying to RAM, making it ideal for firmware and boot code. However, it's more expensive and has slower erase/write operations. NAND flash offers higher storage density, lower cost per gigabyte, and much faster sequential write and erase speeds, making it ideal for mass storage applications. NAND is accessed serially through a shared I/O interface, while NOR has parallel address and data buses allowing random access. NAND requires more complex error correction due to higher bit error rates. 5. What is the difference between UFS and eMMC?UFS (Universal Flash Storage) is the successor to eMMC (embedded MultiMediaCard) and offers several significant advantages: UFS supports full-duplex operation allowing simultaneous read and write operations, while eMMC is half-duplex. UFS uses a faster serial interface with higher bandwidth (up to 11.6 GB/s in UFS 4.0 vs. 400 MB/s in eMMC 5.1). UFS also features command queuing for better multitasking performance, lower latency, and improved power efficiency. These advantages make UFS the preferred choice for modern flagship smartphones and high-performance mobile devices. 6. How does wear leveling work in flash memory?Wear leveling is a technique used to extend flash memory lifespan by distributing write and erase cycles evenly across all memory blocks. Since flash memory has a limited number of program/erase cycles per block, repeatedly writing to the same blocks would cause premature failure. Wear leveling algorithms track the erase count of each block and preferentially use blocks with lower erase counts for new writes. This ensures all blocks wear out at approximately the same rate, maximizing the overall device lifespan. Modern flash controllers implement sophisticated wear leveling algorithms as part of the Flash Translation Layer (FTL). 7. What is 3D NAND technology?3D NAND (also called V-NAND) is a flash memory architecture that stacks memory cells vertically in multiple layers, rather than arranging them in a single planar layer. This technology allows for higher storage densities without requiring smaller manufacturing process nodes. Modern 3D NAND implementations can have over 200 layers, significantly increasing capacity while improving performance and endurance compared to planar NAND. 3D NAND also offers better power efficiency and can achieve higher performance due to reduced cell-to-cell interference. This technology has become the standard for modern SSDs and high-capacity storage devices.

IntroductionInductor is a passive component that used extensively with capacitors and resistors to create filters for analog circuits and in signal processing. Also it is an energy storage device in many switched-mode power supplies. As a major value of inductor, inductance is the ratio of wire current and the magnetic flux which is created by the flow of electrical current in the magnetic field. When a DC current passes through the inductor, there are only fixed magnetic lines around it, which do not change with time. However, when an alternating current is passed through the coil, the magnetic lines around inductor that will change with time.Inductors and Inductance DefinitionCatalogIntroductionⅠ Inductor Working PrincipleⅡ What Does Inductor Do?Ⅲ Inductor Main ParametersⅣ Inductor ClassificationⅤ Chip Inductor5.1 Purpose of a Chip Inductor5.2 Chip Inductor Classification5.3 Three Methods for Reading Chip InductorsⅠ Inductor Working PrincipleWhen ac current is applied to an inductor coil, its own current changes, making its own magnetic flux to change, and then causing induced electromotive force. This phenomenon is called self-inductance. The direction of self-induced current always be affected. When the alternating current increases, the direction of self-inductance current is opposite to that of AC current. When the AC current is weaken, the direction of self-inductance current is the same as that of alternating current, which has blocking effect.1) Self-inductionWhen current flows through the coil, a magnetic field is generated around the coil. When the current in the coil changes, the surrounding magnetic field also changes accordingly. This changing magnetic field can cause the coil itself to generate induced electromotive force (EMF is used to represent the terminal voltage of the ideal power supply for active components).2) Mutual InductanceWhen two inductor coils are close to each other, the change of the magnetic field of one coil will affect the other one, and this effect is mutual inductance. The magnitude of the it depends on the degree of coupling between the self-inductance and the two coils. The components made by this principle are called mutual inductors.Ⅱ What Does Inductor Do?The inductor mainly plays the role of filtering, oscillating, delaying, tuning and frequency selection in the circuit, as well as filtering signal, filtering noise, stabilizing current and suppressing electromagnetic wave interference. The most common role of inductance in a circuit is to form an LC filter circuit together with a capacitor. Capacitors have the characteristic of "block DC and pass AC", while inductors have the function of "pass DC and block AC". It can be made into low-frequency and high-frequency choke coils by making use of its properties. Common filter inductors are for this purpose.➡️Pass DC: It means that in a direct current circuit, the inductor acts as a wire and has no effect.➡️Block AC: In an AC circuit, the inductor will have impedance, that is, XL. The current in the entire circuit will become smaller, which has a certain blocking effect on AC. The self-induced electromotive force is always opposed to the current change in the coil. Mainly can be divided into high-frequency choke coil and low-frequency choke coil.➡️Inductor has the function of generating self-induced EMF, which is also called energy storage function. Like a capacitor, it is also an important energy storage component, which is widely used in switching power supplies. In addition, the phase relationship between the voltage across the inductor and the current: the voltage leads the current by 90 degrees, which is just the opposite of the capacitor. Using this characteristic, inductors and capacitors form LC series and parallel circuits, which can be used for frequency selection. In reality, they have been widely used in circuits, especially in radio circuits.If the direct current accompanied by many interference signals is passed through the LC filter circuit, then the AC interference signal will be consumed by the inductance into heat. When the pure DC current passes through the inductor, the AC interference signal in it will also become magnetic induction and heat energy, the higher frequency is most likely to be blocked by the inductor, which used to suppress the higher frequency interference signal.➡️Tuning and Frequency SelectionThe inductance coil and the capacitor are connected in parallel to form an LC tuning circuit. That is, the natural oscillation frequency f0 of the circuit is equal to the frequency f of the non-AC signal, and the inductance and capacitive reactance of the loop are also equal, so the electromagnetic energy oscillates between the inductor and the capacitor. This is the resonance phenomenon of the LC loop. During resonance, since the inductance and capacitive reactance of the circuit are equal and opposite, the inductance of the total current of the loop is the smallest and the current is the largest (referring to the AC signal of f=f0), so the LC resonance circuit has the function of selecting the frequency, therefore an AC signal of a certain frequency is selected.➡️ChokeIt is used to block low-frequency alternating current, and pulsating direct current flows to pure direct-current in circuits. Go further, it is commonly used in the middle of two filter capacitors at the output of a rectifier circuit. The choke and capacitor form a filter circuit. In the high-frequency circuit: to prevent the high-frequency current from flowing to the low-frequency end, which is commonly as the high-frequency choke of old regenerative radio.➡️FilterIt also prevents the rectified pulsating DC current from flowing to the pure DC circuit. The choke (to simplify the circuit and reduce the cost, replace the choke with a pure resistance) and two capacitors (electrolytic capacitors) form a filter circuit. The use of capacitor charging and discharging and AC choke coil to block the alternating current to smooth direct current and obtain the pure direct current.➡️OscillationWe often say that rectification is to transform AC into DC, so oscillation is the reverse process of it. We call the circuit that completes this process an "oscillator." Oscillator waveform: there are sine wave, sawtooth wave, trapezoidal wave, square wave, rectangular wave, spike wave. The frequency ranges from a few Hz to tens of GHz. It is widely used in the field of wired power and radio.Ⅲ Inductor Main ParametersThe main parameters of inductor include inductance, allowable deviation, quality factor, distributed capacitance and rated current.1) InductanceInductance is also called self-inductance, which is a physical quantity that represents the self-inductance of an inductor. The size of the inductance mainly depends on the number of turns  of the coil, the winding method, the core and its material, etc. Generally, the more coil turns and the denser the coils, the greater the inductance. A coil with a magnetic core has a larger inductance than a coil without a magnetic core. What’s more, a coil with a larger magnetic core has a larger inductance.The basic unit of inductance is Henry, represented by the letter "H". Commonly used units are millihenry (mH) and microhenry (μH). The relationship between them is:1H=1000mH1mH=1000μH2) Allowable DeviationThe allowable deviation refers to the allowable error value between the nominal inductance and the actual inductance.Generally, inductors used in circuits such as oscillation or filtering require high accuracy, with an allowable deviation of ±0.2%~±0.5%; while the accuracy requirements of coils used for coupling and high-frequency blocking are not high; the allowable deviation is ±10 %~15%.3) Quality FactorQuality factor, also called Q value, is the main parameter to measure the quality of an inductor. It refers to the ratio of the inductance presented by the inductor to its equivalent loss resistance when it works under a certain frequency of AC voltage. The higher the Q value of an inductor, the smaller its loss and the higher its efficiency.The Q factor is related to the DC resistance of the coil wire, the dielectric loss of the coil frame, and the loss caused by the core and shield.4) Distributed CapacitanceDistributed capacitance refers to the capacitance that exists between the turns of the coil, the coil and the magnetic core, the coil and the ground, and the coil and the metal. The smaller the distributed capacitance of the inductor, the better its stability. Distributed capacitance can make the equivalent energy dissipation resistance larger. To reduce it, silk-covered wire or multi-strand enameled wire is commonly used, and sometimes honeycomb winding method is also used.5) Rated Current The rated current refers to the maximum current value that the inductor can withstand under the allowable working environment. If the operating current exceeds the rated current, the inductor will change its performance parameters due to heat, and even burn out due to overcurrent.Ⅳ Inductor ClassificationAccording to the form of inductor: fixed inductance, variable inductance.According to the nature of the magnetic conductor: air core coil, ferrite coil, iron core coil, copper core coil.According to work nature: antenna coil, oscillating coil, choke coil, trap coil, deflection coil.According to winding structure: single-layer coil, multi-layer coil, honeycomb coil.According to working frequency: high frequency coil, low frequency coil.According to structural characteristics: magnetic core coil, variable inductance coil, color code inductor coil, non-magnetic core coil, etc. Ⅴ Chip Inductor5.1 Purpose of a Chip InductorChip inductors are electromagnetic induction components wound with insulated wires. It is a commonly used electronic component. The function of the chip inductor: it is simple to say that it can isolate and filter the AC signal or form a resonant circuit with capacitors, resistors, etc. The inductor coil and capacitor in parallel can form an LC tuning circuit. Any current flowing through the chip inductor will generate a magnetic field, and its magnetic flux will act on the circuit.When the current passing through the chip inductor changes, the DC voltage potential generated in the chip inductor will prevent the current from changing. When the current passing through the inductor coil increases, and the current passing through the inductor coil decreases, the self-induced electromotive force is in the same direction as the current, which prevent the current from decreasing and release the stored energy at the same time. The direction of flow is opposite to prevent the increase of current, and at the same time, part of the electric energy is converted into magnetic field and stored in the inductor. Therefore, with inductor filtering, not only the pulsation of load current and voltage is reduced, the waveform becomes smooth, and the rectifier diode is turned on.The role of shielded chip inductors is different from that of the general one. The general chip inductors are not shielded in the circuit to achieve the desired effect. The shielded current instability of this kind inductor in some circuits plays a good blocking role. A metal shield surrounds the positively charged conductor, and the inside of the shield will induce the same amount of negative charge as the charged conductor. A positive charge equal to that of a charged conductor appears on the outside. If the metal shield is grounded, the positive charge on the outside will flow into the ground, and there will be no electric field on the outside, that is, the electric field of the positive conductor is shielded.The shielding inductance also plays a role of coupling in the circuit. In order to reduce the coupling interference voltage of the alternating electric field to the sensitive circuit, the inductance can be set with a metal shield with good conductivity between the interference source and the sensitive circuit, in addition, the metal shield is grounded. The coupling interference voltage to the sensitive circuit depends on the product of the alternating electric field voltage, the coupling capacitance and the ground resistance of the metal shield. As long as the metal shield is well grounded, the coupling interference voltage can be reduced. The electric field shielding is mainly based on reflection, so the thickness of the shielding body does not need to be too large, and the structural strength is the main consideration.5.2 Chip Inductor Classification1) Winding TypeIt is characterized by a wide range of inductance (mH～H), high inductance accuracy, low loss (that is, large Q), large allowable current, strong manufacturing process inheritance, simplicity, and low cost, and the shortcoming is size. For example, the ceramic core winding type chip inductor can maintain a stable inductance and a fairly high Q value at such a high frequency, so it occupies a place in the high-frequency circuit.NL series inductors are wire-wound type, 0.01~100uH, accuracy 5%, high Q value, which can meet general needs. NLC type is suitable for power circuit, rated current up to 300mA.NLV type is high Q value, environmentally friendly (reconstituted plastic), and can be interchanged with NL.NLFC has a magnetic screen and is suitable for power cords.2) Layer TypeIt has good magnetic shielding, high sintering density and good mechanical strength. The disadvantages of it are low pass rate, high cost, small inductance, and low Q value.Compared with wire wound chip inductors, it has many advantages: Small size is helpful to the miniaturization of the circuit.Closed magnetic circuit will not interfere with surrounding components, and will not be interfered by neighboring components, which is beneficial to high-density installation.Integrated structure, high reliability; good heat resistance and solderability.Regular shape is suitable for automatic surface mounting production.MLK type inductor has the characteristics of small size, good solderability, magnetic screen, high-density design, monolithic structure, and high reliability.MLG type has a small inductance and uses high-frequency ceramics, which is suitable for high-frequency circuits.MLK type working frequency is 12GHz, with high Q and low inductance (1n~22nH).3) Film TypeIt has the characteristics of maintaining high Q, high precision, high stability and small size in the microwave frequency band. The internal electrodes are concentrated on the same layer, and the magnetic field distribution is concentrated, which can ensure that the device parameters after mounting do not change much, and show good frequency characteristics above 100MHz.4) Weaving TypeIts characteristic is that the inductance per unit volume at 1MHz is larger than other chip inductors, small in size, and easy to install on the substrate. It is usually used as a miniature magnetic component for power processing.In actual applications, the inductor should be selected according to the situation, circuit requirement, and the material cost.5.3 Three Methods for Reading Chip Inductors1) Digital Position Identification (generally rectangular chip resistors use this nominal method)This method is to use three digits on the resistor to indicate its resistance. Its first and second digits are significant digits, and the third digit represents the number of "0"s added after the significant digits, no letters will appear in this place.For example: "472'" means "4720Ω"; "151" means "1510Ω". If it is a decimal, use "R" to mean "decimal point". It occupies one significant digit, and the remaining two are significant digits.For example: "2R4" means "2.4Ω"; "R15" means "0.15Ω".2) Resistor Color Code (generally cylindrical fixed resistors use this nominal method)Chip resistors are the same as general resistors. Most of them use four rings (sometimes three rings) to indicate their resistance. The first ring and the second ring are significant numbers, and the third ring is the magnification. For example: "brown, green and black" means "15Ω"; "blue, gray, orange and silver" means "68kΩ", the error is ±10%.3) E96 Number Mixes with LetterThis method also uses three digits to indicate the resistance value, that is, "two digits plus one letter". Two digits represent the E96 series resistance. Its third digit is the magnification expressed by the letter code. For example: "51D" means "332×103; 332kΩ"; "249Y" means "249×10-2; 2.49". Frequently Asked Questions about Inductor Uses1. What is inductor and its function?An inductor is arguably the simplest of all electronic components. It's a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. Typically, an inductor will consist of an insulated wire that's wound into a coil, much like a resistor. 2. What is the basic principle of inductor?An inductor is a passive electronic component which is capable of storing electrical energy in the form of magnetic energy. Basically, it uses a conductor that is wound into a coil, and when electricity flows into the coil from the left to the right, this will generate a magnetic field in the clockwise direction. 3. What is the function of inductor in AC circuit?Inductors store their energy in the form of a magnetic field that is created when a voltage is applied across the terminals of an inductor. The growth of the current flowing through the inductor is not instant but is determined by the inductors own self-induced or back emf value. 4. Does an inductor block AC?We know that inductor has inductive reactance property by which it opposes the flow of current through it. The equation of inductive reactance is, ... For this reason, an inductor can totally block the very high-frequency AC. 5. Why AC is blocked by inductor?Since inductor behaves like a resistor, DC flows through an inductor. The AC flowing through L produces timevarying magnetic field which in turn induces self- induced emf (back emf). ... For an ideal inductor of zero ohmic resistance, the back emf is equal and opposite to the applied emf.