Editorial Team

Class A amplifier circuit with small signal model

Class A Amplifier

Class A amplifier Theory A Class A amplifier is the simplest and most fundamental type of power amplifier, widely recognized for its excellent linearity and low distortion. It has poor efficiency, as the device draws a constant current and dissipates significant power even without a signal. Despite these limitations, Class

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Iphone 16 radio frequency board showing power amplifiers and low noise amplifiers

Amplifier Classes

What are amplifier classes? Amplifier classes are categories that describe how an amplifier handles the combination of input signal amplification, linearity, power-efficiency and electromagnetic interference to at a given size and cost. Classification helps engineers, designers, and consumers with essential information about how a particular amplifier operates, and what trade-offs

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Introduction to Transistors

What is a transistor? A modern transistor is an electronic device that uses a semiconductor to amplify or switch electronic signals. It is usually a three-terminal device, where the current through two terminals is controlled using the voltage at the third terminal. Modern transistors are used to create microprocessors, cellular

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Relay

Relays are electronic switches used when an independent low-voltage signal is needed to control a high-power circuit. They commonly use an electromagnet (coil) to operate their internal mechanical switching mechanism (contacts).

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LM317 voltage regulator pin diagram and pin names

LM317 Adjustable voltage regulator

It is an easy-to-use three-terminal adjustable-voltage regulator. The LM317 voltage regulator circuit requires only two external resistors to set the output voltage. If a fixed resistor is connected between the output and adjustment pin, it can also be a precision current regulator.

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full bridge rectifier with ripple suppression capacitor

Bridge rectifier

What is Bridge rectifier? A bridge rectifier is an electrical circuit that converts alternating current (AC) into direct current (DC). It is classified as a full wave rectifier circuit because the output of the circuit is always positive even if the input of the circuit is negative. Unlike half-wave rectifiers,

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stable system waveform and s-domain plot

Stability of control systems

What is stability of control system ? Stability refers to the ability of a closed-loop system to maintain a state of equilibrium or to return to that state after being subjected to disturbances or changes. A stable control system is one in which the output remains bounded and does not

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PWM signal passed through a low pass filter

PWM – Pulse Width Modulation

PWM’s full form is Pulse width modulation. It is a technique used in electronics to encode analog information in form of duty cycle of periodic pulses. It is a common technique used to control the power delivered to electronic devices.

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Clipper Circuits

What is a clipper circuit? Clipper circuits, also known as clippers, limiters, or slicers, selectively remove a portion of an input signal without affecting (distorting) the remaining waveform. They serve as wave-shaping circuits controlling the shape of the output waveform using linear and non-linear elements without using energy-storing components. In

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power factor explaination. Transmission line losses.

Power factor and Power factor correction (PFC)

What is Power factor in AC circuits? Electricity primarily travels through AC waveforms, and the efficiency of this transmission is quantified using the power factor. This factor is derived by dividing the average power by the “apparent” power. The apparent power is computed by multiplying the RMS values of voltage

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Brushed DC motor

What is a Brushed DC motor? Brushed DC motors represent one of the oldest, most cost-effective, and straightforward categories among DC motors. They utilize brushes for transferring current to the motor windings via mechanical commutation. The motor’s characteristics are influenced by the number of coils wound around it and the

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compound excited motor - long shunt and short shunt motor

Types of DC motor

Classification of DC motors DC motors vary based on the arrangement of connections between the field winding and the armature, with options for parallel, series, or both. Another key distinction lies in how the rotor receives power, either through brushes, where current is supplied via brushes, or brushless motors, where

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Circuit diagram of 1-to-8 Demultiplexer using 1-to-2 and 1-to-4 multiplexers. Higher order Demux using lower order Demux

Demultiplexers (DEMUX)

What is Demultiplexer? A demultiplexer, also referred to as a Demux or data selector, functions as a digital circuit receiving a single input signal and logically connecting it to a specific output line among several, decided by control signals. Its fundamental role stands in contrast to that of a multiplexer,

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AND gate symbol and CMOS circuit

Basic Digital Logic Gates

Digital logic gates are essential components in digital circuits, executing logical operations on binary inputs (zeros and ones) to generate binary outputs. They’re interconnected to enable arithmetic, control, and memory operations, forming the basis of processors, memory units, and other digital devices.

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Transmission gates

A transmission gate is a type of analog switch used in digital and analog circuit design. It functions as a bidirectional switch, allowing signals to pass through or be blocked based on control signals. It is commonly used for signal routing, level shifting, isolation, and multiplexing purposes.

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Multiplexers (MUX)

A multiplexer (often abbreviated as “mux”) is a digital circuit that selects one of several input signals and forwards it to a single output. It operates based on control signals to determine which input is transmitted to the output. Multiplexers are widely used in digital systems for data routing, signal

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D Latch and D Flip-Flop

A D latch is a fundamental sequential logic circuit element used in digital electronics. It is commonly used to store one bit of information (either a 0 or a 1) and is a basic building block in constructing more complex circuits like registers, counters, and memory units.

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Schematic of 8 to 3 encoder

Digital encoder and Priority Encoder

What is an encoder? An encoder is a digital circuit that transforms M (< 2N) digital inputs into distinct code outputs (represented by N-bits), symbolizing the input’s position. Usually, 2N > M > N. It finds extensive application in digital systems, facilitating the conversion of many parallel input lines into

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Flip-Flop and Latch

Flip-Flop vs Latch Flip-flops and latches serve as essential components in digital electronics, enabling the storage and transfer of binary data. Latches, being simpler, are foundational elements. In contrast, flip-flops provide enhanced control and synchronization with glitch immunity owing to their edge-triggered functionality. Flip-flops find extensive application in synchronous digital

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Flash ADC

What is a Flash ADC? One of the fastest ways to convert an analog signal to a digital one is to use a flash ADC. This type of ADC can convert very high frequencies of input signals, such as those found in oscilloscopes that operate in the GHz range. However,

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Delta-sigma ADCs

What is Delta-Sigma ADC? The Delta-Sigma (ΔΣ) ADC is a closed-loop oversampling technique involving a 1-bit ADC, an error integrator, and a 1-bit DAC. It is designed to sample a slowly varying input signal multiple times, a process known as oversampling. This setup continuously tracks the input signal to ensure

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Analog to Digital converter

What is an analog to digital converter (ADC)? An Analog-to-Digital Converter (ADC) is an electronic device or circuit that converts continuous analog signals, such as voltage or current, into discrete digital values. It essentially takes an analog input and converts it into a digital representation that can be processed and

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Routh-Hurwitz Criterion

Routh-Hurwitz Stability Criterion The Routh-Hurwitz Stability Criterion is a mathematical technique employed to ascertain whether a polynomial’s roots lie on the left-hand side of the s-plane. It is a valuable tool as it allows one to assess the stability of a system without finding the roots of the characteristic equation. 

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Torque of a DC motor

How is torque generated in a DC motor? When a DC machine operates under load, whether functioning as a motor or a generator, the rotor’s conductors carry current within the magnetic field of the air gap. Consequently, each of these conductors undergoes a force (F=iL X B) as they are

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Supply bypass capacitors

Supply voltage fluctuations, local charge storage, Power supply rejection, Switching noise suppression, High frequency stability of amplifiers and pure analog blocks, Effective series inductance

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Problem simplification using source transformation

Source transformation

Simplification of circuit analysis, Thevein-equivalent circuit, Norton equivalent circuit, multiple simultaneous equations to a single equation with a single variable

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Wattmeter

Electrical power measurement device, Principle of operation, Electrodynamometer, Digital Wattmeter, Applications, Working principle

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Voltmeter

Measurement of voltage, Shunt connection, Analog voltmeter, AC/DC moving iron voltmeter, Digital voltmeter

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Construction of a common ring oscillator

Ring Oscillator

A typical ring oscillator consists of an odd number of NOT gates arranged in a loop, with its output alternating between two voltage levels to represent true and false. These inverters are connected in a series, with the output of the last feeding back to the first. Ring oscillators offer

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oscillator block diagram

Barkhausen Criterion

The Barkhausen criterion is a mathematical condition to determine oscillation frequency. Sometimes it is also used to determine if the circuit is stable or not.

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Voltage controlled oscillator

A voltage-controlled oscillator (VCO) is an electronic oscillator whose output frequency is determined by an input voltage. Frequency is the rate at which the phase changes. A voltage-controlled oscillator enables adjustments to this rate of phase change. Usually, VCOs are derived from known oscillator circuits. Various applications include telecommunications, signal

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Thermistor

Symbol of thermistors, NTC, PTC, Steinhart-Hart equation, Self-heating, Thermal time constant, Applications of thermistors.

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Color sensor

Photodiodes, Pinned photodiodes, RGB color model, Color sensor unit, Bayer mosaic pattern, Lag effect, CMOS active pixel image sensor

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PIR sensor

Working principle of PIR sensor, Detection element, Dual sensor setup, Fresnal lens, Signal processing, Applications of PIR sensor

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Accelerometer

Introduction An Accelerometer is a sensor or device that measures acceleration. It is a fundamental component of many modern technologies and is used to detect changes in velocity or acceleration in various applications. Principle of operation of an accelerometer Accelerometers work based on the principle of measuring the force or

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Virtual short & virtual ground in opamp

Any negative feedback system with significant gain would attempt to minimize the error at the input terminals. This means that the steady-state value of the difference between the two input terminals would be nearly zero. This similarity in two input pins in negative feedback circuits is called virtual short.

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Pipeline ADC

What is a pipeline ADC? A pipeline ADC (Analog-to-Digital Converter) is a type of ADC that divides the conversion process into multiple stages, each of which contributes a portion of the final digital output. In a pipeline ADC, the input signal goes through a sequence of stages, each performing a

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Optoisolators

An optoisolator (or optocoupler) is an electronic component that provides electrical isolation between two circuits using light. It consists of a light-emitting diode (LED) and a photodetector (such as a phototransistor or a photodiode) housed in a single package. The LED emits light when current flows through it, and the

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Hall effect sensors

Hall element, Magnetic field measurement, Hall-sensor V-B characteristics, internal working diagram of Hall-sensor, Head-on detection and sideways detection

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Thevenin’s theorem

Open load voltage (Thevenin voltage), Equivalent resistance by shorting voltage source and opening current sources (Thevenin resistance), Simplified network analysis

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norton theorem

Norton’s theorem

Short load current (Norton current), Equivalent resistance by shorting voltage source and opening current sources (Norton resistance), Simplified network analysis

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Ohm’s law

Ohm’s law defines the relationship between current, voltage, and resistance. It is a fundamental law in electronics—measurement setup of Ohm’s law, Short circuit, and open circuit.

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The Autotransformer

Principle of operation and voltage ratio, Construction and application, Copper savings in auto-transformer, Advantages and Disadvantages of an auto-transformer

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stacked topology to analyse translinear principle

Translinear circuits and principle

The word translinear refers to the property of bipolar transistors (BJTs) where the transconductance of a BJT varies linearly with its collector current. This relationship stems from the logarithmic connection between the collector current and the base-emitter voltage.

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IC 741 Op Amp

IC 741 op amp is the most popular general-purpose operational amplifier in history. It can be found easily in the nearby radio shop. During its time, it was first opamp to solve the phase reversal problem.

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integrator circuit using opamp

Basic Op Amp circuits

Amplifier, comparator, super diode, voltage addition, voltage subtraction, voltage integration, voltage differentiator, voltage to current converter, peak detector, rectifier

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Voltage differentiator

A voltage differentiator is a circuit used in electronics to produce an output voltage that is proportional to the rate of change of the input voltage. In simple terms, it’s a circuit that measures how quickly the input voltage is changing over time.

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integrator circuit using opamp

Voltage integrator

A voltage integrator, also known as an integrator circuit, is a type of analog electronic circuit that performs mathematical integration of an input voltage signal with respect to time. It essentially outputs a voltage proportional to the integral of the input voltage over a certain period of time.

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Non Inverting Op-Amp

In a non-inverting opamp configuration, the output voltage is in the same phase as the input voltage. The input signal is connected to the non-inverting terminal of the opamp.

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Inverting Op-Amp

The inverting operational amplifier is a fixed-gain amplifier producing an opposite output polarity voltage for a given input voltage, as its gain is always negative.

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capacitor specifications

Capacitor specifications

Capacitance, Voltage rating, Polarity, Tolerance, Equivalent series resistance (ESR), Equivalent series inductance (ESL), Tangent loss angle, Leakage current, Temperature stability, Ripple current rating etc

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Capacitors in AC circuits

Capacitive reactance, impedance, phase shift, frequency, Capacitor charging and discharging, current-voltage relationship, filter circuits, AC analysis, power factor correction

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Supercapacitor

Construction of supercapacitor, Principle of operation of supercapacitor, Electrochemical double layer capacitor (ELDC), Difference between Supercapacitor, electrolytic capacitor and Li-ion battery.

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Resistors

Unit of resistance, Ohms, Symbol of resistors and potentiometer, Types of resistors, Resistor color code, Power rating of resistor, Application of resistor

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Solid state relay

Construction, Advantages and disadvantages over electromechanical relays, No moving parts, Input circuit of SSR, Output circuit of SSR, Applications, AC load switching

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Triac

Introduction, Advantages and disadvantages of triac, Symbol and construction of Triac, Operation of Triac, Current-Voltage relationship of Triac, Triac control circuit, Applications of Triac.

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Diac

Bi-directional switch, No gate electrode, Symmetric current-voltage relationship, Triggering of Triacs, Holding current

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Thyristor (SCR)

Silicon-controlled rectifier (SCR), unidirectional, Construction, I-V characteristics, PNPN, Gate, Anode, Cathode, Diode vs SCR, Data-sheet specifications

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Capacitors

Energy storage element, capacitance, parallel plate capacitor, permittivity, dielectric, voltage rating of capacitors

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MOSFET circuit model

Small signal model, high-frequency and low-frequency model, Common Drain, Common Gate, Common Source, Transconductance, thermal noise, flicker noise, capacitances,etc.

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Inductors

Inductance, Circuit analysis, Inductor symbol, Non idealities of inductors, Types of inductor, Air core, Toroidal etc.

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Level shifter circuit

A level shifter circuit is used to convert signals from one voltage level to another while maintaining the shape of the signal. This is commonly needed when interfacing different parts of a system that operate at different voltage levels, such as between microcontrollers, sensors, or other integrated circuits.

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PNP BJT Transistor

Simplified cross-section diagram of PNP BJT, Small signal model, Symbol of PNP BJT, Single stage amplifiers (CE, CC, CB), Biasing a PNP transistor in active mode.

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NPN BJT Transistor

Simplified cross-section diagram of NPN BJT, Small signal model, Symbol of NPN BJT, Single stage amplifiers (CE, CC, CB), Biasing a NPN transistor in active mode.

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Latchup

Parasitic BJT in CMOS, lateral n-p-n and vertical p-n-p, SCR, subtrate resistance, guard rings, Positive feedback, epitaxial process etc.

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R2R ladder digital to analog converter

What is R-2R resistor network/ladder? The R-2R resistor ladder as the name suggest is a network of resistors which has resistors of only two denominations, R and 2R. This network performs a direct conversion of a parallel digital data into an analog voltage. Each digital bit, such as b0, b1,

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SR Latch and SR Flip-Flop

The SR flip-flop and latch, also known as the Set-Reset flip-flop, is a fundamental sequential logic circuit element used in digital electronics. It’s a type of flip-flop that stores one bit of data.

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JK Latch and JK flip-flop

The JK flip-flop is a type of sequential logic circuit that serves as a memory element, capable of storing one bit of binary information. It’s an enhancement of the SR (Set-Reset) flip-flop, addressing the SR flip-flop’s “invalid” state issue when both the Set and Reset inputs are active simultaneously.

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A linear electrical network with two supernodes

Nodal analysis

Kirchoff’s current law (KCL), Reference node, G matrix, Nodal analysis with a voltage source, Super node, Modified nodal analysis

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L293D motor driver IC

What is L293 motor driver IC? A motor driver, commonly an integrated circuit chip, plays a crucial role in managing motors within autonomous robots and control setups. It serves as a crucial intermediary between the microcontroller (such as Arduino) and the motors it directs. Given that motors often demand higher

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Brushless DC motor

What is a Brushless DC motor? Brushless DC motors (BLDC motors), as their name suggests, operate without brushes. Unlike brushed motors where brushes transmit current to rotor coils through a commutator, brushless motors have fixed coils on the stator, while the rotor consists of permanent magnets. In brushless motors, the

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Nyquist stability criteria

Nyquist contour, Nyquist stability criteria, Understanding Nyquist stability criteria using simple examples, Behaviour of poles and zeros in Nyquist plot, Procedure to draw Nyquist plot

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Junction Field Effect Transistor (JFET)

Junction Field-Effect Transistors (JFETs) are three-terminal semiconductor devices used in electronics to provide a robust high impedance with lower noise. JFETs act as voltage-controlled current sources and voltage-controlled switches

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center tapped full wave rectifier

Full wave rectifiers

A full wave rectifier is an electrical circuit used to convert alternating current (AC) into direct current (DC). Unlike half-wave rectifiers, which only use one half of the AC waveform, full-wave rectifiers utilize both the positive and negative halves of the AC cycle, resulting in a more efficient conversion.

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PN junction diode

A p-n junction is a combination of two types of semiconductor materials, p-type and n-type, in a single semiconductor substrate. P N junctions are used to create transistors, pn junction diodes, and isolation between transistors.

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Bandpass filters

Bandpass filter allows signals within a specific range of frequencies, called the passband, to pass through while attenuating signals outside this range.

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active second order high pass filter

Analog Filters

An analog filter is a circuit that selectively allows certain frequencies to pass through while attenuating others. These are made using resistors, capacitors, inductors, transistors, and opamps.

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MOSFET

Energy band diagram, Drift current, Terminals in a MOSFET, Threshold voltage, Small signal model, Channel length modulation, Pinch-off region, Linear region, Capacitances, Noise.

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Buck-Boost converter (Inverter)

What is buck-boost (inverter) converter? A buck-boost converter is an energy-efficient DC-DC (direct current) converter that steps down and inverts the voltage from positive to negative voltages. The name is “buck” because the output is less than the input voltage (e.g., -10V output is less than +3.3V input). It has

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Boost converter (Step-Up)

What is a boost converter? A boost converter is a DC-DC (direct current to direct current) converter used to step up or increase a DC voltage from a lower to a higher level. It is also called a step-up converter. It converts a lower DC voltage input to a higher

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Buck converter (Step-down)

Buck converter definition A buck converter, also known as a step-down converter, is a high-energy efficiency DC-to-DC converter that steps down the input voltage to a lower output voltage while maintaining the same polarity. It uses lossless components like inductors, capacitors, and switches to achieve high efficiency. Output voltage regulation

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Power MOSFET

High power, fast switching, DC model, Switching Model, Specifications of power MOSFET, Channel resistance, Parasitic capacitance, Heat dissipation, Packages available

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root locus plot using matlab

Root locus plot

How to use a root locus plot, Concepts of root locus, Starting and end points of root-locus, Asymptotes of root locus, Angle and centroid, Angle and magnitude criteria, Root locus rules

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stable system waveform and s-domain plot

Phase Margin and Gain margin

Stability in control system, BIBO stable, Marginal Stable Unstable systems, Dominant and non-dominant poles, Phase margin and Gain Margin, Gain crossover frequency and Phase crossover frequency

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bode plot exact using python

Bode plot

What is a bode plot? A Bode plot is a graphical representation of a closed-loop system’s loop-gain LG(s) frequency response. It is a widely used tool in control systems engineering, electronics, and signal processing to analyze and design closed-loop linear time-invariant (LTI) systems. Bode plots provide insights into how a

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Parallel RL circuit

RL (resistor-inductor) circuit

Resistor inductor circuit An RL circuit, also known as a resistor-inductor circuit or RL network, comprises a combination of inductors and resistors and is commonly energized by a power source. It involves connecting an inductor and a resistor in either a parallel or series configuration. These circuits can be driven

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Working principle of DC motor. Showing direction of torque when a current carrying conductor is placed in a magnetic field.

DC motor

What is a DC motor? A DC motor is an electrical machine that converts electrical energy into mechanical energy. Inside a DC motor, the input electrical energy, which is in the form of direct current (DC), gets transformed into mechanical rotation in the presence of a stationary magnetic field. Working

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electronic speed controller for BLDC motor used in drones

Electronic speed controller (ESC) for brushless motors

What is electronic speed controller (ESC)? The ESC, which stands for “electronic speed control”, regulates electric motor speed (throttle) and function, and is widely used in radio-controlled (RC) models (drones), particularly with brushless motors. It offers a 3-phase electric power source and can be a separate unit or integrated within

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Back EMF in a DC motor

What is Back EMF ? As the armature of a DC motor spins within a magnetic field, electromagnetic induction occurs, inducing an electromotive force (emf) in the armature’s conductors, similar to a generator’s operation. This induced emf opposes the applied voltage (following Lenz’s law) and is referred to as back

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RC (resistor-capacitor) circuit

Resistor Capacitor circuit (RC circuit) A resistor-capacitor (RC) circuit is a combination of a resistor and a capacitor connected in series or parallel to a voltage or current source. The resistor restricts the flow of current in the circuit, creating a voltage drop across it proportional to the current passing

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Schmitt trigger

A Schmitt trigger is a type of electronic circuit with hysteresis, primarily used to convert non-linear input signals into digital output signals. It helps in cleaning up noisy signals, squaring up waveforms, and providing a more stable output.

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555 timer IC

555 Timer IC

The 555 timer, introduced in 1972 by Signetics, is a timing generation IC which is popular for its simplicity, affordability, and versatility.

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H-bridge simple representation

H-bridge circuit

What is an H-bridge circuit? An H-bridge circuit forms the fundamental configuration for controlling a DC motor’s direction—either clockwise or counterclockwise. Comprising four switches (made using relays or transistors) arranged in the shape of the letter ‘H,’ this setup allows the motor to move in different directions. Engaging one pair

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model of opamp

Operational Amplifiers (Op Amp)

Op Amp is a short name for operational amplifiers. In electronics, it is used for operations like addition, subtraction, integration, differentiation, logarithms, gain, buffer (to amplify power), etc. That is how the name “operational” is justified.

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Basic LC oscillator without feedback

LC Oscillators

Q factor, Damping factor, Center / Resonance frequency, Condition for oscillations, Active LC oscillator circuit, Tuned circuit, LC Tank circuit

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