IntroductionIn electronics, transient voltage suppressor (TVS) diodes are components that protect sensitive circuitry from being damaged due to high voltage transients. Because tvs diodes are constructed with large cross sectional area junctions for absorbing high transient currents. The primary source of high voltage transients are electrostatic discharge, electrical fast transient, and surge events. This notes will tell you how does a tvs diode work to prevent a circuit malfunction and protect devices.CatalogIntroductionⅠ Transient Voltage Suppressors (TVS)1.1 What Transient Means??1.2 What Causes a Circuit to Be Transient?1.3 What Does a TVS Do?1.4 What Can Be A Transient Voltage Suppressor?Ⅱ Transient Voltage Suppression Diode2.1 TVS Diode Overview2.2 How To Choose A TVS Diode?Ⅲ How Do You Use TVS Diode for Circuit Protection3.1 TVS Diode in Circuits3.2 Major TVS Diode ParametersⅣ ConclusionⅠ Transient Voltage Suppressors (TVS)1.1 What Transient Means?Transients are spikes of short duration in voltage or current that can in several ways damage a circuit. Some transients only occur once, and some of them may be repetitive. These transients vary from a few millivolts to thousands of volts and can last for hundreds of milliseconds to nanoseconds. Due to inductive load switching or defective contacts in switches and connectors, transients may be produced internally. It can be produced externally because of lightning strikes or inductive switching.1.2 What Causes Transient Voltage?Transient voltages are caused by the sudden release of stored energy due to incidents such as lightning strikes, unfiltered electrical equipment, contact bounce, arcing, capacitor bank or generators being switched ON and OFF. Transient voltages differ from swells by being larger in magnitude and shorter in duration. Transient voltages typically last from less than a microsecond to several milliseconds. Transient voltages are generally classified into two different types depending on where they occur on a power system: normal mode or common mode.1.3 What Does a TVS Do?Transient voltage suppressors or TVS are devices of protection used to save the circuits from this unexpected voltage or current spike. Positioning these TVS devices in parallel with the circuit is the primary way to protect a circuit from overvoltage.1.4 What Can Be A Transient Voltage Suppressor?Metal oxide varistor, TVS diode, Zener diode or bypass capacitor are several types of TVS devices that can be used for transient voltage suppression diodes.Transient Voltage Suppressors can be divided into two types, clamping and crowbar. Clamping devices restrict the voltage to a level which is fixed. They consume the excess energy of the overvoltage event in doing so. An instance of clamping devices is TVS diodes.On the other hand, once activated, Crowbar devices effectively shorten the protected line, redirecting the excess energy away from the protected circuit. As you can see in the graph below, when a trigger voltage (spike) is detected, the crowbar device shorts the circuits such that the line voltage is decreased, then the line voltage rises again to a stable state for regular circuit operation after some time as the crowbar device delays the circuit.Transient Voltage Suppression Diode SymbolⅡ Transient Voltage Suppression Diode2.1 TVS Diode OverviewThe transient voltage suppression diode ((ESD protection diode)) is a solid-state PN-Junction diode explicitly designed to remove the sudden or momentary effects of overvoltage on sensitive semiconductors and circuits. TVS diode is a clamping system, so it absorbs the excess energy of the overvoltage event if the induced voltage reaches the avalanche breakdown voltage, and then automatically resets after overvoltage situation. Although it is true that standard diodes and Zener diodes can also be used for overvoltage/transient safety, since standard and Zener diodes are designed for rectification and voltage control, they are not as robust as transient voltage suppressor diodes.How Does Transient Voltage Suppressor Diode Work?2.2 How To Choose A TVS Diode?When selecting a suitable transient suppressor, it is necessary what types tvs diode have? Like every other avalanche diode, a unidirectional transient voltage suppressor diode acts in the forward direction as a rectifier in a circuit, and this unidirectional diode is made to withstand very high peak currents. The unidirectional TVS diode symbol is seen in the picture below, and it's almost like a Zener diode.On the other hand, two mutually opposing avalanche diodes connected in series with each other can represent a bidirectional transient-voltage-suppression diode. In parallel with the system or circuit to be secured, these diodes are connected. These diodes are produced as a single element, unlike the symbol. The Bidirectional TVS Diode symbol is shown in the picture below.Introduction to Transient Voltage Suppressors (TVS) CharacteristicBefore take a tvs diode in circuit, it is critical to specify the peak impulse capability for a given transient waveform. In most diodes, the peak pulse capability will be rated either 8/20µs or 10/1000µs impulse waveform. It is possible to classify Transient Voltage Suppressor Diodes into two groups. One of them is unidirectional, and the other is bidirectional.Ⅲ How Do You Use TVS Diode for Circuit Protection3.1 TVS Diode in CircuitsIn parallel with the system or circuit to be secured, TVS diodes are attached. The TVS system is specifically designed to break down at a particular voltage level and, without sustaining damage, conduct large quantities of current.The TVS diode appears as an open circuit under normal voltage conditions, but a low leakage current is present. The TVS diode junction avalanches when the usual voltage reaches a certain amount and overvoltage is redirected from the safe circuit as a result and shunted through the TVS diode. When the overvoltage goes down, the system automatically resets.In addition, the VI characteristic curve of the tvs diode is similar to that of a Zener diode, TVS diodes are specifically designed, characterized, and tested for transient voltage suppression. By contrast, zener diodes are designed and specified for voltage regulation.3.2 Major TVS Diode ParametersMany types of TVS diodes, equipped for a particular application, are on the market. When selecting a TVS diode to protect an external interface, there are a couple of key parameters you want to pay special attention to. Here is the following parameters in the datasheet to help you find a right TVS diode.Reverse Stand-Off Voltage (VR)The highest voltage that can be applied to the protector without the system actually being triggered is the reverse stand-off voltage. The VR of the system should be equal to, or greater than, the peak operating voltage of the safe circuit. This is to ensure that the regular circuit operation or signal voltage is not clipped by the safety system.Breakdown voltage (VBR)The voltage at which the diode can begin to protect and conduct current is the breakdown voltage. The VBR is usually defined at 1mA.Clamping Voltage (VC)The clamping voltage is the maximum voltage that will be exposed to the safe circuit during the event of the test waveform. The clamping voltage for a 1A or 2A waveform that has an 8μS rise time is given on most datasheets.Peak Pulse Current (IPP)The highest current which the safety system can withstand is the peak pulse current.Ⅳ ConclusionThe TVS diode is commonly used in low-energy circuits and systems for diversion/clamping, and in circuits for ESD safety. Because one advantage of using external TVS diodes is that they typically provide level four IEC ESD protection. Under normal operating conditions, the TVS diode presents a high impedance to the protected circuit. Ideally, the device appears as an open circuit, although a small amout of leakage current is present. TVS diode applications can be found in data and signal lines, memory for microprocessors and MOS, power lines for AC/DC, and telecommunication equipment. Frequently Asked Questions about TVS Diodes1. What is Transient-voltage-suppression diode?A transient-voltage-suppression (TVS) diode, also transil or thyrector, is an electronic component used to protect electronics from voltage spikes. In other words, transient voltage suppressor diodes are very popular devices used to instantaneously clamp transient voltages (e.g., ESD events) to safe levels. 2. How does a transient voltage suppressor diode work?Transient Voltage Suppressor Diode is a clamping device, so whenever the induced voltage exceeds the avalanche breakdown voltage, it absorbs the excess energy of the overvoltage event, and then it automatically resets after overvoltage condition. 3. What does a transient voltage suppressor do?Transient Voltage Suppressors (TVS) are devices used to protect vulnerable circuits from electrical overstress such as that caused by electrostatic discharge, inductive load switching and induced lightning. 4. What does a suppression diode do?A transient-voltage-suppression (TVS) diode, also transil or thyrector, is an electronic component used to protect electronics from voltage spikes induced on connected wires.

Ⅰ IntroductionMost Integrated ICs need a constant voltage that they can work with. They have their own operating voltage, whether it's a basic Logic Gate or a sophisticated microprocessor. 3.3V, 5V and 12V are the most common operational voltages. Although we have batteries and DC adaptors that can serve as a source of voltage, because the voltage from them is not controlled, they can not be directly linked to our circuit design most of the time.Say, we have a 9V battery, for instance, but we need to activate a 5V relay, which obviously works on 5V. What are we doing here?CatalogⅠ IntroductionⅡ Definition and Using of Voltage Regulator Ⅲ A Closer Look at Voltage RegulatorsⅣ Three Terminal RegulatorsⅤ Voltage Regulators: Increase the Output CurrentⅥ Adjustable RegulatorsⅦ Limitations of Voltage RegulatorⅧ FAQⅡ Definition and Using of Voltage Regulator You recall your school days when we were told that voltage drops from resistors. Wouldn't it be an easy fix to only use resistors according to Ohms Law to lower the voltage? But then, depending on the current flowing through them, resistors decrease voltage. The moment your part begins to draw less current, it shoots up and destroys the voltage.You need something better; the voltage, at least not much, does not depend on the load current. The voltage divider is the next easiest repair that comes to your head. This involves two resistors, but hey, they can also operate if they can be crammed in. Another nagging problem-the moment your part begins to draw so much current, the divider sags output-the top resistor can not keep up with the current demand. Now you're really starting to wish you had heard about this in school. By reducing the resistor values, you might resolve this, but that would make the two resistors draw too much current, likely to destroy your current budget and get too hot with the immediate risk of failure. What could be done else? Amplifying! You had, of course, to slog through hours of lectures on that. As a voltage follower, why not add an NPN transistor? The bias of the voltage divider could be connected to the foundation, the rail input of 12V to the collector and the output to the emitter part, and bingo, you solved the problem. The repair works, of course, but it leaves you with a nagging feeling-you've used three pieces, and you find out on checking that bugs are perfectly repeated on the performance in the 12V supply rail. This is an amplifier, of course, and it doesn't have the intellect to compensate for itself. You can replace the voltage divider's bottom resistor with a Zener diode, but the current needed to correctly bias a Zener (against things such as temperature coefficients and drift) is almost as much as your part consumes, which is pointless. Isn't there an easier way for this to happen? Isn't there a magic black box containing anything needed to effectively drop the voltage? Similar cycles of stress (including me) have influenced millions of EEEs around the world. Of course, not all issues are correlated with falling voltages, but EEE labs are popular in similar situations everywhere! But you're in luck—there is the exact part you need. In fact, the humble voltage regulator is one of the earliest commercial implementations of the IC technology (apart from op-amps).If you ever look at a voltage regulator's datasheet, you'll be amazed at the circuitry with which they have been packed to drop a voltage and keep it clean-a nice stable voltage regulator, feedback and compensation amplifiers, and a half-good power level. Of course, if we were able to cram so much technology into our own phones, why not make a nice TO-92 kit with some voltage control? Some of them consume no more than a few nanoamps, which is a thousandth of a millionth of an amp! They keep getting stronger every day. Even better, some come with protection against short circuits and overtemperature, rendering them foolproof.Ⅲ A Closer Look at Voltage RegulatorsThe primary role of a voltage regulator, as we have seen in the section above, is to drop a larger voltage to a smaller one and keep it steady, as the regulated voltage is used to power (sensitive) electronics. As mentioned above, a voltage regulator is essentially a beefed-up emitter follower-a transistor linked to a stable reference that spits out a constant voltage, dropping the remainder. They also have an error amplifier built-in, which samples the output voltage (through a divider again), compares it to the reference voltage, calculates the difference, and drives the output transistor accordingly. This is far from a voltage divider, which replicates the input signal faithfully, but at a smaller magnitude. You don't want to see your DC voltage rail overlaid with an AC ripple.A transistor with a high gain is ideal, because power transistors are a massive pain to drive, with pathetic gains in the two-digit range. By using Darlington transistors and, more recently, MOSFETs, this has been solved. As these types require less power to drive, there is a decrease in overall current consumption. This is balanced by the fact that very little current is often absorbed by the voltage reference used internally. The current absorbed by the regulator to drive all this internal circuitry is called the quiescent current when the output is not loaded. The lower the current of silence, the stronger. There are three transistors on the power output level, two of them in a Darlington configuration and the other as a current limiting unit, the way these regulators are designed. The successive CE junctions add up to a voltage drop across the regulator of about 2V. This voltage is known as the voltage dropout, the voltage at which the regulator ceases controlling.With a voltage drop of about 0.4V, you can find devices called LDOs or low dropout regulators, because they use a MOSFET switch.Ⅳ Three Terminal RegulatorsEnough speaking, now for the actual numbers of the pieces. The 78XX series is the most common series of voltage regulators. For example, the 7805 is a 5V regulator and the 7812 is a 12V regulator. The two digits after the 78 reflect the output voltage of the regulator. A wide range from 3.3V to 24V covers the output voltages available with fixed regulators with pleasant values such as 5V, 6V, 9V, 15V and 18V available. For most purposes, this series of regulators are outstanding, they can handle up to almost 30V at the input and up to 1A output current depending on the kit. Attach the input pin to the input voltage and the output pin to the unit that requires the lower voltage and, of course, the ground pin to ground. They are exceptionally easy to use. Since the feedback amplifiers 'reject' input ripple and noise, ensuring that they do not move on to the output, decoupling capacitors are optional here. However, if more than a few tens of milliamps are drawn by your unit, at least 4.7uF on the input and output is recommended, preferably in ceramic. Using these regulators, an odd thing people do is make rudimentary phone chargers. Only add a 9V battery to the input and a suitable USB connector to the output, and you've got an emergency phone charger for yourself. Thanks to the built-in thermal safety on the chip, this design is very robust. A positive thing about these kinds of voltage regulators is that the pinouts are almost interchangeable, so it is possible to plug-in replacements. Most of the 'transistor' packages on PCBs nowadays are voltage regulators that can be picked up because they are so easy to use for other projects.Ⅴ Voltage Regulators: Increase the Output CurrentThe performance current, which is heavily restricted by the package and the way the package is installed, is one limitation that easily overcomes the utility.These regulators have high-current versions, but they are difficult to identify.DC-DC switching converters are the only machines capable of spitting out high currents, but the performance noise figures are awful.It is possible to build your own high current linear regulator, but inevitably you will run into all the above-mentioned issues.Luckily, with a few extra bits, there is a way to 'hijack' a normal regulator and increase the product currently.Most of these modifications include inserting a bypass transistor across the regulator and, as shown in the figure below, driving the base with the input. Ⅵ Adjustable RegulatorsIt's very pleasant and simple to use three-terminal regulators, but what if you want a non-standard output voltage like 10.5V or 13V?Of course, fixed regulators can be hijacked more or less, but the necessary circuitry is very complex and beats the primary objective of simplicity.Devices exist that can do the job for us, with the LM317 being the most common.The LM317 is just like every other linear regulator with an input and an output pin, except there's a pin named 'adjust' instead of a ground pin. This pin is intended to receive input through the output from a voltage divider such that the pin is always at 1.25V, we can obtain various voltages by changing the resistance values. The datasheet also states,' removes several fixed voltages being held,' but this only applies, of course, if you can afford to have those two resistors on board. A good thing about adjustable regulators like this is that they can also act as continuous current supplies with a minor configuration change.The regulator aims to maintain a constant 1.25V throughout the output resistor and thus a constant current on the output by attaching a resistor to the output pin and the adjustment pin to the other end of the resistor as shown in the figure. For the diode laser group, this simple circuit is very common.This can also be achieved by fixed regulators, but the dropout voltages are unreasonably high (in fact, the rated output voltage). However, they can work in a pinch if you're desperate. Ⅶ Limitations of Voltage RegulatorThe greatest benefit of linear regulators is their simplicity; it is not important to say anything else. However, they come with their own set of limitations, like all good chips. Linear regulators work with feedback like a variable resistor, falling any unneeded voltage. The same current as the load is drawn when drawing. This wasted energy is converted to heat, rendering these regulators at high currents warm and inefficient. A 5V regulator with a 12V input that runs at 1A, for example, has a power loss of (12V-5V)*1A, which is 7W! That's a lot of wasted energy and that's just 58 percent production! So, regulators have pathetic energy efficiency at high input-output voltage differentials or high currents. Using more than one regulator in a series of decreasing output voltages (up to the desired voltage value), the input-output differential voltage problem can be solved so that the voltage is lowered in steps. Although the total dissipation of power is the same as having one regulator, the heat load is distributed through all devices, reducing the overall operating temperature. By using a switching supply, the power and efficiency constraints can be resolved, but the option is application-dependent, there are no straight cut rules as to when to use which type of power supply. Ⅷ FAQ1. What is Dropout Voltage or headroom in Voltage regulators?A linear regulator such as the famed 7805 outputs 5.0 volts. The dropout specification is going to be about 2 Volts typical, 2.5 maximum. That means it will regulate 5 V as long as the input unregulated voltage is above 2 to 2.5 V above the regulated output voltage of 5 V. That gives it a 2 volt (7 minus 5) headroom. The headroom is considered to be the minimum input-output differential it can maintain. if the input falls to 6.5 volts the regulator outpupt can be expected to be about 4.5 volts. It means, counting diode drops, and ripple amplitude, you must keep above the dropout voltage or you will see the ripple in your output. 2. How does a voltage regulator work?It works on the principle of detection of errors. The output voltage of an AC generator obtained through a potential transformer and then it is rectified, filtered and compared with a reference. The difference between the actual voltage and the reference voltage is known as the error voltage. This error voltage is amplified by an amplifier and then supplied to the main exciter or pilot exciter. Thus, the amplified error signals control the excitation of the main or pilot exciter through a buck or a boost action (i.e. controls the fluctuation of the voltage). Exciter output control leads to the controls of the main alternator terminal voltage. 3. Can a voltage regulator convert AC to DC?Depends on the topology and the circuit components that are used.A circuit that converts AC to DC is called a rectifier. Additional circuits like buck-boost converters can be used to regulate the DC.In a generic sense, most voltage regulators are marketed for AC systems. They are back-to-back converters which rectify AC to DC and then invert DC to AC after suitable modification to the wave shape. It is possible to take the intermediate DC output after the rectification stage and suitably modify it with further circuitry. 4. What are the 2 types of voltage regulators?Two types of regulators are used: step regulators, in which switches regulate the current supply, and induction regulators, in which an induction motor supplies a secondary, continually adjusted voltage to even out current variations in the feeder line. 5. How do you use a voltage regulator?The first 0.33uF capacitor shorts any AC noise on the line to the ground and cleans the signal up for the input of our regulator. The regulator in this circuit is a TS7805CZ (5V 1A) regulator, which then steps the 12V voltage signal down to 5V, and pushes this on the output. 6. What is the difference between voltage stabilizer and voltage regulator?Basically, no major differences. A stabilizer has only a limited input voltage range and is mostly used for low power devices and the regulator has a higher range of input voltages, for medium and high power devices. Both ensure a regulated, constant output voltage. Stabilizers are a type of voltage regulator. 7. Where are voltage regulators used?Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators and central power station generator plants, voltage regulators control the output of the plant. 8. What causes voltage regulator failure?There are different reasons why the regulator rectifier fails. ... Ground connections are important for good voltage, and if there is faulty voltage, the regulator rectifier can run hot. Bad grounding, corroded battery connection and poor or loose battery connections will cause faulty voltage. 9. What is the purpose of an automatic voltage regulator?An automatic voltage regulator (AVR) is an electronic device that maintains a constant voltage level to electrical equipment on the same load. The AVR regulates voltage variations to deliver a constant, reliable power supply. 10. How long does a voltage regulator last?For the most part, the instrument voltage regulator is supposed to last for the life of the car. Like with any other electrical component of a car, eventually, this voltage regulator will begin to show signs of damage. 

IntroductionIC packaging refers to the material that contains a semiconductor device. The package is a case that surrounds the circuit material to protect it from corrosion or physical damage and allow mounting of the electrical contacts connecting it to the printed circuit board (PCB). Let's take a look at some of the different types of packaging options you can use to enhance your product & customer experience.CatalogIntroductionⅠ How Do You Find the Right IC Packages?Ⅱ What are IC Made Up of?Ⅲ How Many Types of IC Packages Are There?3.1Through-hole Technology (THT)3.2 Surface-mount Technology (SMT)3.3 Through-Hole vs Surface MountⅣ IC Packages Selection SummaryⅠ How Do You Find the Right IC Packages?There was a lot of change in the way electronics components appeared or packaged, from bulky vacuum tubes to lightweight SMD ICs. Because IC packaging indicates the dimension and shape of a chip, to minimize the number of components on board, manufacturers are actively working to reduce the size of ICs, and multiple components are also being increasingly incorporated into LSI, VLSI, and ULSI designs. Almost all components are currently available in two or three different package forms, from which the engineer can pick the one that best fits device application. We will learn about the various IC package forms in this article and where they can be useful.Types of IC | IC Package Types ExplainedⅡ What are IC Made Up of?Before introducing the various forms of IC packages, we can learn about the process of IC manufacturing firstly. ICs consist of monolithic, hybrid, or film circuits, as a matter of fact. The development steps for the IC are as follows:LithographyIt is a technique for defining a pattern in which a photoresist material is added to the wafer surface evenly and then baked to harden. Later, light is projected and selectively extracted via a reticulum containing mask details.EtchingThe undesired materials are separated from the wafer surface.DepositionMaterials are added to the wafer through the process of Physical Vapor deposition and chemical vapor deposition.Chemical Mechanical PolishingA planarization technique by the application to the wafer surface of a chemical slurry with etchant agents.OxidationOxygen (dry oxidation) or HO (wet oxidation) molecules convert silicon layers to silicon dioxide on top of the wafer in the oxidation process.Ion implantationThe most commonly used method for the semiconductor incorporation of dopant impurities. The ionized particles are accelerated and targeted at the semiconductor wafer via an electrical field.DiffusionFor annealing bombardment-induced lattice defects, a diffusion phase following ion implantation is used.IC Design & Manufacturing Process OverviewⅢ How Many Types of IC Packages Are There?A very huge variety of integrated circuits have different packaging requirements. Based on how they are placed on a circuit board, the packages are divided into two types.3.1Through-hole Technology (THT)Through-hole MountingThey are designed to trap the lead pins on one side of the board and smolder on the other side. Compared to other forms, they are larger in scale. These are mainly used in electronic equipment to compensate for the limitations of board space and expense. One example of through-hole mount packages is dual inline packages.DIP and ZIPThrough-hole mount packages come in ceramic and plastic forms to add up to the classification.The most widely used IC packages are Dual Inline Packages (DIP). As in 28-pin ATmega328, the pins are positioned parallel to each other, extending perpendicularly and laid out on a rectangular black plastic housing. The pins are 0.1 inches apart. Additionally, because of the variation in the number of pins in various packages, the box differs in size. They range in number from 4 to 64. These pins are positioned in a way that they can be changed without short-circuiting each other or even smoldering into PCBs at the center of a breadboard.The few common types are Plastic Dual In-Line Package (PDIP) and Molded Dual In-Line Package (MDIP). There are several types of DIP packages. It can further be categorized as:Norm - The most prevalent packaging is this. The pins are spaced apart by 0.1". Skinny - The space between the terminal rows in this box is 7.62mm.Shrink - Identical to the regular ones, but 1.778 mm is the lead pitch. Smaller in size, they use packaging with high pin density.Zig-Zag in Line Packages (ZIP)- Pins are inserted perpendicular to the circuit board in this kind of package. In the box, these pins are aligned perpendicularly and are closer to each other. This style of packaging was short-lived and was primarily used in RAM chips that were dynamic. CER-DIP comprises other types of through-holed packages in which the lead pitch is 2.54 mm and the body is molded with ceramics. Also, glass is the sealing medium used here. The lead pitch of the Pin Grid Array (PGA) is 2.54 mm and the body is made of ceramic. The pins from the body are arranged vertically and can be positioned on a grid. Typically, this one fits a multi-pin kit.3.2 Surface-mount Technology (SMT)Surface Mount DefinitionThe technology of installing or positioning the components directly onto the printed circuit board surface is accompanied by surface mount packaging. While this manufacturing process helps to rapidly do stuff, it also raises the likelihood of defects. This is due to component miniaturization and also because they are placed very close to each other. This, in fact, results in the detection of the deficiency in the entire process becoming extremely significant. Again, ceramic or plastic molding is often used in Surface Mount packaging.Types of SMTThe following are the various types of surface mount packages that use plastic molds:(1) Small Outline L-leaded PackageThis type has leads of the gull-wing type that draw in a L fashion from the body in either direction and can be placed directly on the frame. QFP (Quad Flat L-leaded Packages)-These are SOP-like. The only difference, however, is that the leads are drawn out in 4 directions instead of 2 and are directly placed on the frame. They even come with a heat sink and a heat spreader built in.(2) Ball Grid Array (BGA)A ball grid array (BGA) is a type of surface-mount packaging (a chip carrier) used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. As for BGA soldering, the solder balls on the package have a very carefully controlled amount of solder, and when heated in the soldering process, the solder melts. Surface tension causes the molten solder to hold the package in the correct alignment with the circuit board, while the solder cools and solidifies.3.3 Through-Hole vs Surface MountThe two kinds of packaging have their individual advantages and disadvantages - primarily through-hole mounting and surface mounting. Here's a comparison with different variables between through-hole and surface mount devices that adjust the need for the form of IC packages.1. Size - In contrast with through-hole packages, surface mount packages are smaller.2. Component density - Component density as well as attachment density are comparatively higher for surface mounting packages.3. Assembly- In contrast to through-hole packages that can not afford even the smallest of errors when making holes, minor errors are immediately corrected by the molten solders that bring components close together due to stress in surface mounting packages. This is because, once made, the alignment can not be changed.4. Electromagnetic compatibility - The ability of various electronic devices and components, even in the presence of other devices that produce electromagnetic waves, to operate correctly. Packages for surface mounting have better EMC performance.5. Cost - Because of automated processes, the manufacturing cost is often lower than that of through-hole packages.Surface mount packages do not, however, operate together with a simple plugin on the breadboard. They need a pin-led carrier to be installed. Or worse, they can need special PCBs customized separately for various prototypes.Ⅳ IC Packages Selection SummaryICs are put into protective packages to allow easy handling and assembly onto PCBs and to protect the devices from damage. Therefore, a suitable package type is important for ic applications. First of all, let us emphasize enough how important it is to have good packaging. To allow smooth handling and installation on the printed circuit boards, integrated circuits are placed into packages. To prevent any kind of harm and corrosion, it is extremely imperative to bring ICs into packages. The packages also assist in the dissipation of the heat generated. This is, however, the final part of the entire fabrication process. Consider certain important factors, such as assembly capacity, strength, cost, and connectivity, before deciding on the type of packaging that best suits you.With the ever-present innovations, several kinds of semiconductor integrated circuits packages have appeared. The motive is to choose for yourself the correct type of IC package that is affordable and yet does not compromise with efficiency. Most important thing, chips with the same electronic parameters may have different package types. Frequently Asked Questions about Types of IC Packages1. What is IC package design?IC packaging refers to the material that contains a semiconductor device. The package is a case that surrounds the circuit material to protect it from corrosion or physical damage and allow mounting of the electrical contacts connecting it to the printed circuit board (PCB). 2. What are the different types of IC packages?DIP (Double In-line Package)SOP/SOIC/SO (Small Outline Package)QFP (Quad Flat Package)QFN/LCC (Quad Flat Non-leaded Package)BGA (Ball Grid Array Package)CSP (Chip Scale Package) 3. What is the most common type of digital IC package?DIP (Dual in-line packages)DIP, short for dual in-line package, is the most common through-hole IC package you'll encounter. These little chips have two parallel rows of pins extending perpendicularly out of a rectangular, black, plastic housing. 4. How many types of IC are there?TwoThere are two main types of integrated circuits: digital ICs or analog ICs. 5. What are the types of packaging materials?Different Types of Packaging Materials1) Plastic. The most common packaging methods in industries is plastic.2) Aluminum. Aluminum is widely used for products such as sodas, beer, canned goods and animal foods.3) Cardboard. Most products that are packaged in cardboard boxes are first wrapped in another type of packaging such as bubble wrap or foam.4) Glass5) Foam

Ⅰ IntroductionAs the technology evolved, several improvements from a standard fuse to the circuit breaker have also been made to the safety devices. We have been using static relays and magnetic relays for years to secure an electrical network, and now the safety systems have also changed as the microprocessors have evolved.We've heard about various kinds of relays before, and Numerical Relay was one of them, so we're going to concentrate more on this kind of relay today. The formed type of a static and electromagnetic relay is numeric relays. They are a system used in an electrical network to calculate electrical parameters and transform them into numerical data that is mathematically and logically interpreted to determine whether to activate an electrical network. A numerical relay's primary function is to protect the electrical network from unpredictable currents of failure. Due to their flexible features, numerical relays are often favored. A single numerical relay can track various parameters, such as current, voltage, frequency, time of onset, time of offset, etc. And for the analysis and control of multiple faults such as over current, over flux, different current and more, the same relay can be used.CatalogⅠ IntroductionⅡ Working and Hardware Architecture of Numerical RelayⅢ Types of Numerical Relays  3.1 Based on Logic  3.2 Based on Characteristics  3.3 Based on Actuating Parameters  3.4 Based on ApplicationⅣ ConclusionⅤ FAQⅡ Working and Hardware Architecture of Numerical RelaySince they both have identical hardware architecture with minor variations, the numeric relay can be considered a miniature device.Their architecture can seem overwhelming, but all of the architecture in these major categories can be simplified.• Input Module• CPU• Memory• Multiplexer and Analog to digital converter• Output module• Digital input/Communication module Input ModuleThe power system uses analog parameters to operate. With existing transformers and future transformers, the high-powered analog signals are stepped down. Using lowpass filters, it is fed to the numeric relay. Owing to the corona or induction effect from a nearby high voltage line, the low pass filter is used to remove the noisy signal in the device. CPUThe central processing unit (CPU) is the system's brain, which processes and filters all data protection algorithms and digital inputs. MemoryThere are two memories, RAM and ROM, in the numerical relay. Random Access Memory (RAM) is responsible for the retention and processing of input data to the relay during compilation.Read-Only Memory (ROM) is the relay's storage unit. It stores the required software and other data related to events and disturbances. The Storage Unit is a must because it allows during the occurrence of a fault to evaluate and troubleshoot any incident. Multiplexer and Analog to digital converterOnly digital data can be processed by the CPU, but the feedback from the current transformer and future transformer is analog. The Analog to Digital converter is then used to translate the signal to digital data. A multiplexer is used to select the necessary analog input for conversion if multiple analog signals need to be converted. Output ModuleThe digital contacts that are actuated when a trip command is provided by the CPU are the output module. Pulses that are produced as a response signal are these digital contacts. According to the application of the relay, the response time may be modified. Digital input/Communication moduleAs with a computer, a relay also has serial and parallel ports to link the relay to the substation's control and communication systems. To extend the tripping command, the Auxiliary relays can be attached to the digital output contacts.Ⅲ Types of Numerical RelaysFor different types of safety, numerical relays are used and are graded based on characteristics, logic, parameters of action and application. Although they are categorized under different circumstances, their function remains the same, in the event of a fault in the electrical network, to enable the travel system.3.1 Based on LogicSuch classifications are made based on the relay's logical operation.• Over Current/ Earth Fault: It will cause the circuit breaker when excessive current flows through a device. Used for protection against transformers and feeders.• Directional overcurrent: When the fault forces the power to flow in a specific direction, it is controlled (Opposite to the specified direction). Used for the safety of transformers, generators, and bus bars.• Differential:  When the phase difference of two or more equivalent electric quantities exceeds the stated value, the differential relay is set to trip. It can protect transformers from localized faults and generators.• Under/ Over Voltage: Under such conditions, the voltage in an electric network may drop or rise below or above a fixed value, the circuit is tripped.• Distance: The function of this type of relay is dependent on the distance between the fault impedance and the location of the relay. They are primarily used to safeguard transmission lines.3.2 Based On CharacteristicsThese classifications are based on their tripping property• Instantaneous relay: If the trigger is triggered directly after a fault occurs, no time delay will occur.• Definite Time Relay: Only activated if the fault stays in place after a certain time.• Definite Minimum Time (IDMT) Inverse Time Relays: These relays are often used on transmission lines. When the line current is higher than the safe value, the circuit breaker is triggered.• Voltage restraint over current relay: The relay is only triggered if the conditions of both under-voltage and over-current arise at the same time.3.3 Based on Actuating Parameters• Current relays• Voltage relays• Frequency relays• Power relays Etc.3.4 Based on Application• Primary relay• Backup relayThe entire network could crash if the security system fails, so they use the backup relay. And if the primary relay goes wrong, doing this would help us secure the machine.Ⅳ ConclusionNumeric relays are often used for automatic safety in the generating stations and substations. Different components such as feeder, engine, generator, transmission line, transformers and bus bars can be secured by such relays. Relays are available from different firms, such as Siemens, ABB, Schnieder Electric, Alstom, Texas, etc. Each business has its own software that can help us communicate with their relays and program the security algorithm. You can construct your own algorithm for security and feed it to the relay once you know about the parameter and the various types of faults that could occur in a power system. It doesn't take years of training and practice to become an expert in the defense of the power system to become one overnight. To become an expert, keep learning and keep on investigating.Ⅴ FAQ1. What is numerical protection relay?Numerical relay is the relay in which the measured AC quantities are sequentially sampled and converted into numerical data that is mathematically and/or logically processed to make trip decisions. Numerical relay is actually the digital relay as a unit for which manufacturers has developed standardized hardware, which can be used in conjunction with suitably developed software to meet variety of production requirements and applications. 2. What is the difference between a relay and a fuse and a circuit breaker?A relay is a control component used for signalling or switching according to control voltage applied to it’s terminals. A fuse is a protective device to limit the let through energy based on the current limit being exceeded. These are used once & then disposed of (not re-usable.) The fuses can be selected according to application & rated current (IE a motor, transformer or capacitor protection device) A circuit breaker (CB) is also a protection device used to limit let through energy on a fault, also with different thermal characteristics according to application & some LV units with a variable current threshold & tripping curve. A CB has limits - IE on LV systems, some are rated say 35kA, other larger units 60 or 80kA according to the system & calculated worst case fault current. 3. What is meant by numerical relay?In utility and industrial electric power transmission and distribution systems, a numerical relay is a computer-based system with software-based protection algorithms for the detection of electrical faults. Such relays are also termed microprocessor-type protective relays. 4. What is numerical overcurrent relay?A 'Numerical over Current Relay' is a type of protective relay which operates when the load current exceeds a preset value. ... The overcurrent relay of IDMT is the relay that starts to operate after the intended time delay. The time delay is also known as operation time. 5. What are the advantages of numerical relay?• Compact Size. • Flexibility. • Reliability. • Multi-Function Capability. • Different types of relay characteristics. • Digital communication capabilities. • Modular frame.• Low burden. 6. Which transistor is used in the numerical relay?The high-powered analog signals are stepped down with the current transformer and Potential transformer. It is fed to the numeric relay using a lowpass filter. The low pass filter is used to eliminate the noisy signal in the system due to the corona or induction effect from a nearby high voltage line. 7. What is the difference between numerical relay and static relay?A big difference between conventional electromechanical and static relays is how the relays are wired. ... Electromechanical and static relays have fixed wiring and the setting is manual. Numeric relays, on the other hand, are programmable relays where the characteristics and behavior can be programmed. 8. How does a numerical relay work?Numerical relays use a specialized digital signal processor (DSP) as the computational hardware, along with associated software tools. The relaying voltage and currents are passed through an isolation transformer. 9. What do you mean by a numerical protection scheme?Numerical protection relays are digital systems in constant communication with substation automation systems through menu-driven interfaces. They have configurable binary inputs, outputs, and programmable logic. They monitor, measure, and record electrical values, faults and disturbances, and events. 10. What are the demerits of numerical relay?1 relay can perform only 1 function. There are some disadvantages of the microprocessor are given below, The microprocessor has a limitation on the size of data. Wide Range of setting, more accurate, Low burden hence low VA of CT is required which minimizes the cost. 

IntroductionAn operational amplifier, or op amp is used in a wide variety of applications in electronics. It generally comprises a differential-input stage with high input impedance, an intermediate-gain stage, and a push-pull output stage with a low output impedance. Common operational amplifier has two input pins and one output pin. Its basic role is to amplify and output the voltage difference between the two input pins. So what are these op-amp parameters meaning? This note tells you the typical parameters of op-amp and their definitions, also there have several examples with specific values to explain deeply for you. CatalogIntroductionⅠ How Does An Op Amp Work?Ⅱ Understanding Basic Op-amp Parameters2.1 What are the Parameters of Op Amp?2.2 Questions about Op Amp Important ParametersⅢ Common Op-amp ICs Datasheet OverviewⅣ ConclusionⅠ How Does An Op Amp Work?An op-amp is a multi-stage , direct coupled, high gain negative feedback amplifier. It is basically a three-terminal device which consists of two high impedance inputs. Ideally, it only amplifies the difference in voltage between the two, also called differential input voltage. Op-amps are still a primary building block for analog systems, performing tasks like amplification, active filtering, and signal transformation. In digital systems, op-amps are used in buffers, analog-to-digital converters, digital-to-analog converters, and regulated power supplies, to name a few applications.Ⅱ Understanding Basic Op-amp ParametersOp-amps are linear devices that are ideal for DC amplification and are used often in signal conditioning, filtering or other mathematical operations. So understanding its basic parameters is important to employ it well in circuits.Parameters Of Op-Amp2.1 What are the Parameters of Op Amp?Gain Bandwidth1) Gain bandwidth product: Due to parasitic junction capacitance and minority-carrier change storage in devices, the voltage gain of op amp decreases at high frequencies, it refers to the bandwidth and gain product.2) Unity gain bandwidth: As the input signal of the frequency increases, the open-loop gain drops off until it finally reacts to the value 1. The frequency at which the gain reduces to 1 is defined as unity gain frequency or unity-gain bandwidth.Input Offset VoltageIt is a very small voltage applied at the outputs, to make the output terminal zero of the operational amplifier. It reflects the symmetry of the the op amp circuit. The better the symmetry, the smaller the input offset voltage.Input Offset Voltage DriftThe input offset voltage drift is also called the temperature coefficient. In a given temperature range, it is the ratio of the change in the input offset voltage to the temperature change. This parameter is actually a supplement to the input offset voltage. Within a given operating range, the magnitude of the drift of the amplifying circuit depends on the temperature changes.Input Bias CurrentWhen the output current voltage of the op amp is zero, input bias current refers to the average value of the bias current of the two input terminals that flows into the inverting and non-inverting input terminals of the Op-Amp. It has a greater impact on the places where the input impedance is required, and it is generally related to the manufacturing process. The smaller the input bias current the smaller the drift.Input Offset CurrentWhen the output current voltage of the op amp is zero, input offset current means the difference between the bias currents of the two input terminals. It also reflects the symmetry of the circuit inside the op amp. The better the symmetry, the smaller the input offset current.Input Resistance1) Differential mode input impedance: when the operational amplifier is working in the linear region, it is the ratio of the voltage change at the two input terminals to the corresponding current change. It includes input resistance and input capacitance, and only refers to input resistance at low frequencies.2) Common mode input impedance: It is the ratio of the input current change when the op amp is inputting a signal, that is, the same signal is input at the two input terminals of the op amp. At low frequencies, it appears as a common-mode resistance.Output ResistanceWhen the operational amplifier works in the linear region, a voltage signal is added to the output terminal of the operational amplifier, output resistance means the ratio of the voltage change to the corresponding current change. At low frequencies, it only refers to the output resistance of the op amp. This parameter needs to be tested in an open loop state.Voltage Gain1) Open-loop gain: the amplification factor of the op amp without negative feedback (in open loop state). The ideal value is infinite, generally about thousands to tens of thousands of times, and it represents by dB and V/mV.2) Closed-loop gain: in the case of negative feedback, it refers to the amplifier magnification.Voltage SwingWhen the op amp is working in the linear region, voltage swing is the maximum voltage amplitude that the op amp can output under the specified load and the current power supply voltage.Input Voltage Range1) Differential mode input voltage range: The maximum differential mode input voltage is defined as the maximum allowable input voltage difference between the two input terminals of the operational amplifier. When the input voltage difference of the op amp exceeds it, the input stage of the op amp may be damaged.2) Common mode belongs to the rabbit voltage range: when the operational amplifier is working in the linear region, when the common mode rejection ratio of the operational amplifier deteriorates significantly is the maximum common mode input voltage. It limits the maximum common-mode input range in the input signal, therefore, special attention is required in the case of interference.Slew RateThe slew rate of the op amp is defined as the input of a large signal (including a step signal) to the input under the closed loop condition. It indicates how fast the output of OP-AMP can change in response to change in input frequency. The output rise rate of the op amp is measured from the output of the op amp. Since the op amp is in a closed loop state during conversion, the feedback loop of the op amp does not work, that is to say, the slew rate has nothing to do with the closed loop gain.CMRRThe Common Mode Rejection Ratio (CMRR) is defined as the ratio of the differential voltage gain to the common-mode voltage gain.Unity GainA unity gain amplifier is an amplifier that has a gain of 1 that also means there is no gain. The output voltage will be the same as the input voltage it is commonly known as a voltage follower amplifier.Common Mode Rejection RatioWhen the op amp works in the linear region, it means the ratio of the differential mode gain of the op amp to the common mode gain. It is an extremely important indicator, it suppresses differential mode interference signals. Since the common-mode rejection ratio is very large, the common-mode rejection ratio of most op amps is recorded and compared in decibels.Supply Voltage Common Mode Rejection RatioWhen the op amp works in the linear region, it means the input offset current of the op amp varies with the supply voltage. Supply voltage common mode rejection ratio reflects the impact of power supply changes on the output of the op amp. Pay special attention when used for DC signals or small signals.Equivalent Input VoltageA well-shielded op amp without signal input, any AC interference voltage generated at its output end, when this noise is converted to the input of the op amp, it is called the input noise voltage (sometimes also expressed by noise current).2.2 Questions about Op Amp Important ParametersWhy do op amps need negative voltage?Op-amps themselves don't have a 0V connection but their design assumes the typical signals will be more towards the center of their positive and negative supplies. Thus, if your input voltage is right at one extreme or forces the output toward one supply, chances are it won't work properly. Why op amp has high gain?The gain of an op amp represents how much greater in magnitude its output will be than its input, hence its amplification factor. This is usually defined as an open-loop gain or large signal voltage gain. Why Positive feedback is not used in op amp?In an op-amp circuit with no feedback, there is no corrective mechanism, and the output voltage will saturate with the tiniest amount of differential voltage applied between the inputs. What is CMRR?The Common Mode Rejection Ratio (CMRR) is defined as the ratio of the differential voltage gain to the common-mode voltage gain. CMRR is infinity. Why CMRR should be high?A high CMRR is required when a differential signal must be amplified in the presence of a possibly large common-mode input, such as strong electromagnetic interference (EMI). An example is audio transmission over balanced line in sound reinforcement or recording. What is the maximum gain of op amp?The maximum gain is the open loop gain. It depends on the opamp model, and can go anywhere from 60 dB to 120 dB voltage gain. The open-loop bandwidth is however very small. Another issue is that this gain is very variable between different parts of the same product number due to variations. What is slew rate of op amp?Slew rate (SR) is the maximum rate of voltage change that can be generated by the op-amp's output circuitry. It is measured as voltage relative to time, and the typical unit used in datasheets is volts per microsecond (V/µs). SR is infinity, which means the ideal op-amp will produce a change in the output instantly in response to an input step voltage. What is bandwidth of an operational amplifier?The operational amplifiers bandwidth is the frequency range over which the voltage gain of the amplifier is above 70.7% or -3dB (where 0dB is the maximum) of its maximum output value as shown below. Is higher slew rate better?Higher slew rates are not always better: Higher slew rate makes for higher operating current. This means higher power consumption. Faster slew rate will make higher bandwith. Ⅲ Common Op-amp ICs Datasheet OverviewLM741The LM741 series are general-purpose operational amplifiers which feature improved performance over industry standards like the LM709. It is intended for a wide range of analog applications. It has only one op-amp inside. An operational amplifier IC is used as a comparator which compares the two signal, the inverting and non-inverting signal.Figure 1. LM741 Op Amp PinoutTable 1: LM741 SpecificationsMax supply voltage: ±22 VVoltage gain: 200V/mVMax input voltage: ±15 VBuilt-in output short circuit protectionMax output short circuit current is 40 mA.Input resistance: 6MMax low offset voltage of 6mv and can drift 15 µV/°CApplications include comparator, dc amplifier, summing amplifier, integrator or differentiators and active Filters.Max input offset current of 70nA and can drift up-to 0.5 nA/°C.Max Bandwidth is 1.5Mhz;Max Slew rate is 0.7 V/us.Max CMRR is 90 dB.Similar Products: UA741, µA741Max peak output voltage swing is 16VOperating temperature range –50 to 125 °C LM709 SeriesThe LM709 series is a monolithic operational amplifier in tended for general-purpose applications. The precursor to the popular LM741 is the LM709. The 709 had no internal frequency compensation, unlike the 741. Frequency compensation is used to purposely limit an operator's bandwidth. As the input frequency increases, the operator's phase shift also increases. This can contribute to unnecessary oscillation, as an unintended phase-shift oscillator forms the feedback network.Figure 2. LM709 Op Amp PinoutTable 2: LM709 SpecificationsMax supply voltage: ±18VInput resistance: 750KMax input voltage: ±10VOutput resistance: 150ΩMax low offset voltage of 6mv and can drift 6 µV/°CApplication includes voltage follower, basic comparator, multivibrator and frequency generator.Max input offset current of 500nA and can drift up-to 22.8 nA/°CPackage: TO-5, Pin Nb=8Max CMRR is 70dB.Similar parts: OP77, UA70Peak output voltage swing is 24VOperating temperature range –55 to 125 °C LM1458LM1458 is a dual general purpose Operational Amplifier (Op-amp). Its has two built-in amplifiers having common power supply, and short circuits protected and require no external components for frequency.Figure 3. LM1458 Op Amp PinoutTable 3: LM1458 SpecificationsMax supply voltage: ±18 VInput resistance: 1MΩMax input voltage: ±15VMax CMRR is 90dBvoltage gain: 15V/mVbuilt-in output short circuit protectionMax low offset voltage of 6mv and can drift 15 µV/°CInput offset current of 300nA max and can drift up-to 0.5 nA/°CMax peak output voltage swing is 14V.Max bandwidth is 1MHz.Operating temperature range 0 to 70 °CApplications include summing amplifiers, portable devices, comparators, integrators, etc.Similar Products: MC1458Packages have TO-CAN, DSBGA, SOIC and PDIP. LM324The LM324 series are low−cost, quad operational amplifiers with true differential inputs. They have several distinct advantages over standard op amps. It is a single supply, high gain, internally frequency compensated quad op amp. And it can be operated from a single or split power supplies.Figure 4. LM324 Op Amp PinoutTable 4: LM1324 SpecificationsMax supply voltage: 32 VOutput resistance: 350ΩVoltage gain: 100 V/mVMax output short circuit current is 60 mAInput bias current: 100nABuilt-in output short circuit protectionMax low offset voltage of 3mv and can drift 30µV/°CMax input offset current of 30nA and can drift up-to 300 pA/°CMax CMRR is 85dB.Max peak output voltage swing is 16V.Bandwidth is 1MHzOperating temperature range 0 to 70 °CPackages: 14-pin PDIP, 14-pin CDIP, 14-pin SOIC, and 14-pin TSSOP NE5532Compared to the standard dual op amps, the NE5532 is a Dual Low Noise Op-Amp in 8-pin package commonly used as amplifiers in audio circuits for its noise immunity and high output drive capability. The Op-Amp is internally compensated for high unity gain with maximum output swing bandwidth, low distortion and high slew rate.Figure 5. NE5532 Op Amp PinoutTable 5: NE5532 SpecificationsMax supply voltage: ± 15VInput bias current: 1000nAMax supply current: 10mALow offset voltage: 5 mVInput offset current: 200nABuilt-in output short circuit protectionMax output short circuit current is 60 mAInput resistance: 300KΩMax CMRR is 100dB.Output resistance: 0.3ΩMax peak output voltage swing is 26V.Max bandwidth is 10Mhz.Max slew rate is 9 V/us.Operating temperature range -65 to 150 °CApplications include Av Receivers, Audio mixer, High-performance audio preamplifier and many more.Ⅳ ConclusionOp amps are used in a wide variety of applications in electronics. Some of the more common applications are: as a voltage follower, selective inversion circuit, a current-to-voltage converter, active rectifier, integrator, a whole wide variety of filters, and a voltage comparator. Based on your circuit requirements, you should check out datasheets of different op-amps and select one.

Ⅰ IntroductionIf you've been around electrical equipment for a long time, you may have heard of the transformer. Yeah, they're the enormous bulky things found in the corners of the street that make random scary noises and spit sparks sometimes. There is also a sort of small transformer in your phone charger, but much, much smaller and with a different mechanism.CatalogⅠ IntroductionⅡ Transformer DefinitionⅢ Importance of Transformers in Electrical SystemⅣ Transformer SymbolsⅤ Working Principle of a TransformerⅥ Transformer PropertiesⅦ Transformer Construction  7.1 BOBBIN  7.2 CORE  7.3 WINDINGSⅧ Transformers ApplicationⅨ ConclusionⅩ FAQⅡ Transformer DefinitionA transformer is a device that converts one voltage or current to another using the principles of electromagnetism. It consists of a pair of wounds around a magnetic core of the insulated wire. The winding to which the voltage or current to be converted is connected is called the primary winding and the secondary winding is called the output winding. Transformers come in two types: step up, which increases the voltage or current, and step down, which lowers the input of the voltage or current. The transformers in your microwave oven, for example, are a secondary transformer that is used in the microwave oven to supply about 2200Volts to the vacuum tube. One thing to remember is that transformers only operate with AC voltages or adjustments and do not work with DC. We'll understand why now. Ⅲ Importance of Transformers in Electrical SystemIt was around 1856 that there was a rivalry between two brilliant minds, Nikola Tesla and Thomas Edison. Those were the days when electricity and its applications were merely noticed by glowing a lamp and driving a motor. It was Edison and his associates who first discovered the DC (Direct Current) system, and then Tesla developed his AC (Alternating Current) system sometime after that. The two have since tried to show that their scheme is more advantageous than the other. The time has come for houses to get electricity by then. Although Edison was busy showing how dangerous AC is by electrocuting elephants, Tesla and his team came up with the transformers that made it much simpler and more effective to transmit electricity. Also, transformers play a key role in the transmission system today. Let's learn why. High-voltage and low-current transmission of electricity will help us minimize the thickness of the transmission wires and thus the cost, which will also improve the system's performance. For this purpose, a typical transmission system may be anywhere from 22KV to 66KV, although some generators have an output voltage of only 11kV in the power plant and need only 220V/110V for the household AC unit. So where does this transfer of voltage take place and who does it? Transformers are the answer to the issue. There will be transformers in the system from the power plant to your home that will either step-up the voltage (increase voltage) or step-down (decrease voltage) to preserve the system's efficiency. The transformers are therefore referred to as the heart of an electrical transmission system. In this post, we will be learning more about them. Ⅳ Transformer SymbolsFor a transformer, the circuit symbol is simply two inductors placed together side by side that share the same center. The type of core used is shown by the existence of the line between the two windings: a dashed line represents ferrite, two parallel lines represent laminated iron, and no line represents the core of air.The number of 'bumps' is often used as a rough measure of the role of the transformer-less bumps on one side and more on the other which means that there is a lower number of turns on the first side than the other.Ⅴ Working Principle of a TransformerWe need to go back in time, to the laboratory of Michael Faraday, to understand the operation of a transformer. Perhaps the father of the transformer can be named Michael Faraday, as it was his experiments that helped us understand electromagnetism and create devices such as motors and generators. There was a race to try to create a practical system that could harness the strength of magnets to produce electricity in the late 1800s when it was discovered that electricity and magnetism were related phenomena. Faraday figured out that by bringing a magnet close to a coil of wire, electricity could be produced. What he discovered was that only when the magnetic field shifts can the voltage be produced, that is, whether either the coil or the magnet is shifted relative to the other. In DC, the movement of the current is constant and so is the magnetic field. There is no voltage generated on the secondary because the field is constant and not changing and the transformer just looks like a regular coil of resistive wire to the power supply. So, with DC currents, transformers do not operate. He also found that a current flowing in one coil might cause the current in the other coil when two coils of wire were held close to each other. This definition is referred to as mutual inductance, which governs the operation of all modern transformers.The transformer consists of two windings wound on a magnetic core, as shown in the figure. The goal of having a core is that air is not a very good magnetic field supporter, so having a magnetic core increases the magnetic field for a certain amount of current flowing through one winding, which in turn generates a stronger current in the other, improving the device's overall performance. A magnetic field is built up in the core as a current moves through the primary and is limited mostly to the core. This magnetic field passes through the center of the secondary and, thus, the law of reciprocal induction causes a current in the other. The beauty of this method is that the ratio between the input voltage and the output voltage is simply the ratio between the main and the secondary windings, summarized by the following formula:Vout/Vin = Nsec/NpriVin is the input voltage, Nsec is the number of turns in the secondary winding, and Npri is the number of turns in the main winding, where Vout is the output voltage.So if you have two transformers, one with 100 turns on the primary and 1000 turns on the secondary and one with 10 turns on the primary and 100 turns on the secondary, you can measure the ratio of turns to be 1:10 on both of them, so that they both increase voltage to the same degree. Ⅵ Transformer PropertiesIf we take a closer look at the above example, the first transformer would have higher winding resistance (since more wire is used) and will restrict the amount of current that can be drawn from the transformer in certain instances. This property is called winding resistance, but since the copper wire used normally has a low resistance, it does not matter in most cases. Another thing you see is that the main and secondary windings have no direct electrical connection. This is called galvanic isolation and, as we can see, can be very useful. Looking at each of the transformer windings, we can see that they are shaped like inductors and also have an inductance, a coil of wire wrapped around a magnetic center. This inductance, given by this formula, is proportional to the square of the number of turns:Lpri/Lsec = Npri2/Nsec2Where Lpri is the primary winding inductance, Lsec is the secondary winding inductance, Npri is the number of turns on the primary windings and Nsec is the number of turns on the secondary windings. The proportionality constant can be found in the datasheet for a given core and is typically given in μH/turn2 units. The exact value is based on the core form and scale. Suppose you have a transformer core with a 1uH/turn2 specification. If you wind one winding on that heart, the value of the constant multiplied by the number of turns squared will be the inductance, in this case, 1. So the winding inductance of that one will be 1μH. If you wind the same core with another winding with 10 turns, then the inductance will be:(1µH/turn2)*(10 turns)2 = 100µHSince the windings have inductance, they provide an impedance to AC signals, given by the formula:XL = 2π*f*LWhere XL is the impedance in ohms, f is the frequency in ohms and L is the inductance in Henries.Say, you want to design a transformer at 50Hz, which is the standard power line frequency, that draws 3A at 220V AC. Then, by Ohm's law, the impedance of the main will need to be 73.3 Ohms. Now that we know the appropriate impedance and the frequency, we can rearrange the formula to find out the inductance required for the winding:L = (XL)/(2π*f)Substituting the values, we find that 233mH would be the required inductance.We can calculate the windings necessary to get the inductance needed using this information and the value of μH/turns2 from the datasheet.Assuming the value is 50μH/turns2, we can rearrange the formula to evaluate the inductance: Where N is the number of turns, L is the inductance required, and the term t2/μH is just the inverse of the value of the datasheet.We get the necessary number of turns of 2158 when adding our values to the formula. So, as you can see, you can build transformers for almost any application once you get the hang of the formulas! Ⅶ Transformer ConstructionAn awareness of transformer construction is vital for someone who wants to wind their own transformers.A transformer is made up of a few fundamental components: 7.1 BOBBINFor every transformer, the bobbin is the fundamental structure. It provides a spool on which the windings will wind and keeps the core in place as well. It is typically composed of plastic that is heat resistant. It also sometimes involves metal pins onto which, for example, you can weld the ends of the windings if you want to mount it to a PCB. 7.2 COREPerhaps the most significant aspect of the transformer is this. The cores can come in several shapes and sizes, as seen in the image. It is the core's magnetic properties that decide the transformer's electrical properties that are built around the core. 7.3 WINDINGSThe wire used in the house, though it can seem like a trivial item, is as critical as any other element. In general, solid enameled copper wire is used because the insulation is strong and thin, so plastic insulating sheaths do not waste space. Ⅷ Transformers Application • MAINS VOLTAGE CONVERSIONThis is possibly the most common transformer application, stepping down the mains voltage for low voltage devices. This stuff, like microwaves and old TVs and wall brick power supplies, you might even find inside. These transformers have iron cores that make them bulky and much less efficient than other types, providing excellent permeability.Three secondary wires mark them as 12-0-12 or 6-0-6. If you make the center wire the ground reference, this means that the outer two wires have an output of 12V AC RMS. If you calculate the 12v winding over each, you get 24V AC RMS. This gives you the flexibility to use the transformer as you may like. • SWITCH MODE POWER SUPPLIESThese are very specific type of power supplies that generate a DC output and take a DC input. Both modern phone chargers are located here. The transformers used in these PSUs are shaped more like medium- to high-permeability inductors with a limited number of turns and ferrite cores. For a brief period, a DC voltage is applied across the 'primary' so that the current ramps up to a certain amount and retains some magnetic energy in the core. At a lower voltage, this energy is then passed to the secondary, since it has a smaller number of turns. They work and achieve outstanding efficiencies at high frequencies and are very thin. • ELECTRICAL ISOLATIONThere are special transformers with a 1:1 turn ratio, such that the voltages of the input and output are the same. They are used to decouple equipment from the earth's mains. Since mains are referred to as earth, touching even one wire will lead to a shock since the return path is simply the ground. The unit is separated from the main earth by the use of isolation transformers, as transformers are galvanically insulated. • VOLTAGE CONVERSION TRANSFORMERSMany countries use 220V AC as the normal supply voltage around the world, but some countries use 110V AC, such as the US. This means that it is not possible to operate certain devices such as blenders in all countries. To this end, transformers that convert from 110V to 220V or vice versa can be used to ensure that appliances can be used in any region. • IMPEDANCE MATCHINGThere are unique transformer types that are used to balance the source and load impedance. RF and audio circuits are commonly used.The ratio of turns is equal to the source's square root and load impedance. • AUTOTRANSFORMERThis is a special type of transformer that has only one winding that forms the secondary with a 'tap' output. This tap is normally variable, so the output AC voltage can be varied, much like a voltage divider. Ⅸ ConclusionTransformers are useful instruments and it can be very useful to learn how to build and operate with them! Although we have covered the basics here, it is something that can be discussed in another whole article to build a transformer right from scratch, so for some other time. But now, you'll know why it's there and how it works when you see a transformer again. Ⅹ FAQ1. How does a transformer convert AC into DC?The transformer is not designed to convert ac to dc. It is a pure AC device used to step down/up voltage levels keeping frequency, power, FLUX constant. In mobile charger, we use transformer along with bridge rectifier to convert domestic AC supply to dc. (with ripples) Finally, such a transformer that converts ac to dc is not designed yet. 2. Will a transformer work with DC?Transformers work in the principle of Faraday's law of 'mutual induction', in which an EMF is induced in the transformer's secondary coil by the magnetic flux generated by the voltages and currents flowing in the primary coil winding. As in DC(voltage being always constant), the change in flux is zero so no mutual induction, thus transformers can't work with a DC supply. Moreover, if DC or a similar rating of AC(Voltage & Current) is fed into the terminals of a Transformer there is a high possibility that it would burn the primary coil. 3. What is a transformer's simple definition?Transformer, device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage. 4. What is the use of a transformer?Transformers are most commonly used for increasing low AC voltages at high current (a step-up transformer) or decreasing high AC voltages at low current (a step-down transformer) in electric power applications, and for coupling the stages of signal-processing circuits. 5. What is the basic principle of a transformer?A transformer consists of two electrically isolated coils and operates on Faraday's principle of ‘mutual induction’, in which an EMF is induced in the transformer's secondary coil by the magnetic flux generated by the voltages and currents flowing in the primary coil winding. 6. What are the two types of transformer?The different types of transformer are Step up and Step down Transformer, Power Transformer, Distribution Transformer, Instrument transformer comprising current and Potential Transformer, Single phase and Three phase transformer, Auto transformer, etc. 7. What are the main parts of the transformer?There are three basic parts of a transformer:• an iron core that serves as a magnetic conductor,• a primary winding or coil of wire.• a secondary winding or coil of wire. 8. What does a transformer look like?A transformer keeps wired doorbells powered at the right voltage for optimal operation. It looks like a small metal box and can be silver, off-white, or even brass colored. If your doorbell is no longer working, you may need to troubleshoot the transformer in order to perform the repair. 9. What is a transformer ratio?The transformer turns ratio is the number of turns of the primary winding divided by the number of turns of the secondary coil. The transformer turns ratio provides the expected operation of the transformer and the corresponding voltage required on the secondary winding. 10. What are the ideal transformers?A transformer that doesn't have any losses like copper and core is known as an ideal transformer. In this transformer, the output power is equivalent to the input power. The efficiency of this transformer is 100%, which means there is no loss of power within the transformer.