Collector Modulation Circuit – Working, Advantages and Disadvantages

Collector Modulation Circuit – Working, Advantages and Disadvantages: 

In Collector Modulation Circuit, the transistor Q1 makes an RF class C amplifier. The carrier signal is applied to the base of Q1. VCC makes collector supply used for biasing purpose. Also, the transistor Q2 makes a class B amplifier which is used to amplify the audio or modulating signal.

Base Modulation Circuit Working Principle

Base Modulation Circuit Working Principle:

The carrier signal from a crystal oscillator is coupled to the base terminal of the amplifier through transformer T1.

Emitter Modulation – Circuit Diagram and its Operation

Emitter Modulation – Circuit Diagram and its Operation:

The carrier signal from a crystal oscillator is coupled to the base of amplifier through capacitor Cin. The modulating signal is applied to the emitter circuit. The capacitors Cin and CC are so chosen so as to bypass carrier frequency only.

Square Law Diode Modulator – Circuit Diagram and its V-I Characteristics

Square Law Diode Modulator – Circuit Diagram and its V-I Characteristics:

Square Law Diode Modulator utilizes the nonlinear region of voltage-current dynamic characteristic of a P-N diode. This square law diode modulator method is suited at low voltage levels because of the fact that current-voltage characteristic of a diode is highly nonlinear, particularly in the low voltage region

Generation of DSBSC Signal using Balanced and Ring Modulator

Generation of DSBSC Signal using Balanced and Ring Modulator:

Balanced modulator may be defined as a circuit in which two nonlinear devices are connected in a balanced mode to generate a DSBSC signal.

Single Sideband Modulation (SSB)

Single Sideband Modulation (SSB):

Phase Shift Method of Single Sideband Modulation SC Generation method uses two balanced modulators and two phase shifting networks. This method avoids the use of filters.

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Amplitude Detection Process

Amplitude Detection Process:

The process of demodulation demands that the modulated wave has some definite average value and the carrier wave is separated out. Hence in demodulation of an AM wave two operations, viz. rectification of the modulated wave and elimination of the RF component of the modulated wave are involved.

Square Law Detector Circuit and Working Principle

Square Law Detector Circuit and Working Principle:

The square law detector circuit is used for demodulating modu­lated signal of small amplitude (i.e., below 1 V) so that the oper­ating region may be restricted to the nonlinear portion of the V­-I characteristics of the device.

Linear Diode Detector or Envelope Detector

Linear Diode Detector or Envelope Detector:

Diode detection is called the envelope detection as it recovers the audio frequency signal envelope from the composite signal. Diode detector is also called the linear detector as its output is proportional to the voltage of the input signal.

Simple Slope Detector – Circuit diagram and its Characteristics

Simple Slope Detector – Circuit diagram and its Characteristics:

Simple Slope Detector circuit consists of a tuned circuit which is slightly detuned from the carrier frequency ωc. In other words, the circuit uses two tuned circuits which are tuned to two different frequencies.

Balanced Slope Detector – Working, Advantages and Disadvantages

Balanced Slope Detector – Working, Advantages and Disadvantages: 

This circuit employees two slope detectors connected back to back to the opposite ends of a centre tapped secondary of the transformer. Thus voltages supplied to the two sides are in phase opposition.

Foster Seeley Detector – Circuit Diagram, Working and its Phasor Diagram

Foster Seeley Detector – Circuit Diagram, Working and its Phasor Diagram:

This Foster Seeley Detector circuit consists of an inductively coupled double tuned circuit in which both primary and secondary coils are tuned to the same frequency (intermediate frequency).

SCR as Half Wave Rectifier Circuit Diagram

SCR as Half Wave Rectifier Circuit Diagram:

SCR as Half Wave Rectifier:

SCRs are very useful in ac circuits where they may serve as rectifiers whose output current can be controlled by controlling the gate current. An example of this type of application is the use of SCRs to operate and control dc motors or dc load from an ac supply.

SCR as Full Wave Rectifier Circuit Diagram

SCR as Full Wave Rectifier Circuit Diagram:

SCR as Full Wave Rectifier:

For Two SCR as Full Wave Rectifier are connected across the centre taped secondary, as shown in Fig. 26.32 (a). The gates of both SCRs are supplied from two gate control supply circuits.

What is DIAC? – Symbol, Construction, Operation and Applications

What is DIAC? – Symbol, Construction, Operation and Applications:

A diac is an important member of the thyristor family and is usually employed for triggering triacs. A diac is a two electrode bidirectional avalanche diode which can be switched from off-state to the on-state for either polarity of the applied voltage.

Shockley Diode Equation, Symbol, Operation and Applications

Shockley Diode Equation, Symbol, Operation and Applications:

The four layer diode, also called the Shockley diode after its in­ventor Willian Shockley, is essentially a low-current SCR without a gate. It is classified as a diode because it has only two exter­nal terminals viz. anode and cathode.

Gate Controlled Switch (GCS) Circuit – Operation and Advantages

Gate Controlled Switch (GCS) Circuit – Operation and Advantages:

Gate controlled switch is designed for easy opening with a reverse-biased trigger. A GCS is closed by a positive trigger and opened by a negative trigger (or by low-current drop out).

Silicon Controlled Switch (SCS) – Symbol, Operation, Advantages and Application

Silicon Controlled Switch (SCS) – Symbol, Operation, Advantages and Application:

Silicon controlled switch (SCS), like the SCR, is a unilateral, four layer, three junction P-N-P-N silicon device with four electrodes namely cathode C, cathode gate G1, anode gate G2 and the anode A

Light Activated SCR (LASCR) – Symbol, Construction and Operation

Light Activated SCR (LASCR) – Symbol, Construction and Operation:

Light activated SCR is just an ordinary SCR except that it can also be light triggered. Most LASCRs also have a gate terminal for be­ing triggered by an electrical pulse just as a conventional SCR.

Power BJT – Construction, Operation and its Characteristics

Power BJT – Construction, Operation and its Characteristics:

Power transistors are large-area devices. Because of differences in geometry and doping concentrations, their properties tend to vary from those of the small-signal devices.

UJT Triggering of SCR Working Principle

UJT Triggering of SCR Working Principle:

One common application of the unijunction transistor is the triggering of the other devices such as the SCR, triac etc.

UJT Relaxation Oscillator – Circuit Diagram and its Workings

UJT Relaxation Oscillator – Circuit Diagram and its Workings:

UJT Relaxation Oscillator consists of UJT and a capacitor C which is charged through resistor RE when interbase voltage VBB is switched on.

UJT as Over Voltage Detector Circuit Diagram

UJT as Over Voltage Detector Circuit Diagram:

A simple dc overvoltage detector circuit is given in Fig. 26.96. It operates on the fact that the device remains switched off as long as the input voltage remain less than the peak point voltage VP of the UJT and as soon as input volt­age exceeds VP, the device is switched on.

Single Phase Full Wave Controlled Rectifier (or Converter)

Single Phase Full Wave Controlled Rectifier (or Converter): 

In case of Single Phase Full Wave Controlled Rectifier (or Converter) both positive and negative halves of ac supply are used and, therefore, the effective value of dc voltage is high and ripple content is less compared to half-wave rectifiers.

Single Phase Dual Converter Circuit Diagram with Four Quadrant of Operation

Single Phase Dual Converter Circuit Diagram with Four Quadrant of Operation:

We have seen that Single Phase full Converters with inductive loads allow only a two-quadrant operation. If two of these full converters are connected back to back, it is known as Single Phase Dual Converter

Three Phase Converter Circuit

Three Phase Converter Circuit:

Three phase converter could be half-wave, semiconverter, full-converter and dual converters. The 3-phase half-wave converter drives are only of theoretical importance and are generally not employed in industrial applications.

Step up Chopper – Definition, Circuit Diagram and its Working Principle

Step up Chopper – Definition, Circuit Diagram and its Working Principle:

In Step up Chopper, techniques by which the output of a chopper obtained is higher than the supply voltage. Such types of choppers are called Step up Chopper.

Step up Step down Chopper or Buck Boost Converter – Working Principle

Step up Step down Chopper or Buck Boost Converter:

A chopper can also be used for stepping up or down the supply voltage by varying its duty cycle. This is also known as a buck-boost converter.

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Step up Step down Chopper or Buck Boost Converter – Working Principle: 

Step Down Chopper with RLE Load Working Principle

Step Down Chopper with RLE Load Working Principle: The Step Down Chopper with RLE Load is shown to consist of a force-commutated thyristor, it could well be a transistor switch.

AC Regulator – Definition and Classification

AC Regulator – Definition and Classification:

AC regulators are classified as single-phase or three-phase. Each of these may be half-wave (i.e., unidirectional) or full-wave (i.e., bidirectional).

Three Phase Cycloconverter – Types, Working and Applications

Three Phase Cycloconverter – Types, Working and Applications:

Three Phase Cycloconverter:

A cycloconverter converts ac at one frequency to an ac of another frequency. Cycloconverters can be classified as single-phase to single-phase, three-phase to single-phase and three-phase to 3-phase devices.

Single Phase Full Bridge Inverter

Single Phase Full Bridge Inverter:

In this inverter, number of thyristors and diodes is twice of that in a half-bridge inverter. It consists of four thyristors and four diodes.

What is Switching Circuit?

What is Switching Circuit?: 

The switching circuit essentially consists of a switch and an associated circuitry. The switch is the most vital part of the switching circuit

Transistor as a Switch Circuit Diagram and Working

Transistor as a Switch Circuit Diagram and Working:

Figure shows the output characteristics of a typical transistor for a CE configuration. The dc load line for a given collector supply voltage VCC and collector resistance RC is drawn on the output characteristics.

Switching Characteristics of Power MOSFET

Switching Characteristics of Power MOSFET:

Switching Characteristics of Power MOSFET:

witching Characteristics of Power MOSFET have the advantage of switching a large current off faster than a BJTs can because a power MOSFET does not have minority carriers.

Multivibrator definition and Types (Astable, Monostable and Bistable)

Multivibrator definition and Types (Astable, Monostable and Bistable):

Multivibrator definition and Types:

A multivibrator is basically a two stage R-C coupled amplifier with positive feedback from the output of one amplifier to the input of the other

Astable Multivibrator Definition and its Working

Collector Coupled Astable Multivibrator:

Collector Coupled Astable Multivibrator:

It is essentially a two-stage R-C coupled amplifier with the output of first stage coupled to the input of second stage; and the output of second stage coupled to the input of the first stage.

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Monostable Multivibrator – Operation, Types and Application

Monostable Multivibrator – Operation, Types and Application: Types of Monostable Multivibrators:

Collector-coupled monostable multivibrator

Emitter-coupled monostable multivibrator.

Bistable Multivibrator – Working and Types

Bistable Multivibrator – Working and Types:

A bistable multivibrator, as its name implies, has two stable states. It can stay in either of the two states indefinitely (as long as dc power supply remains on).

Commutating Capacitor in Bistable Multivibrator or Speed up Capacitor

Commutating Capacitor in Bistable Multivibrator or Speed up Capacitor:

Commutating Capacitor in Bistable Multivibrator is also called as Speed up Capacitor. Whenever a triggering pulse is applied to change the bistable state from one bistable state to another, it is necessary that the transition period should be minimum and it should require minimum but finite amount of energy.

Triggering in Digital Electronics | Types

Triggering in Digital Electronics | Types: 

Triggering in Digital Electronics is the process of applying an external signal to induce transition from one state to another.

Blocking Oscillator – Definition, Operation and Types

Blocking Oscillator – Definition, Operation and Types:

Types of Blocking Oscillator:

1.Monostable Blocking Oscillator

2.Astable Blocking Oscillator

Op Amp IC 741 Pin Diagram and its Working

Op Amp IC 741 Pin Diagram and its Working: 

The schematic diagram and Op Amp IC 741 Pin Diagram is shown in Fig. 33.4 (a) and in Fig. 33.4 (b). It is not necessary to understand every detail about the circuit design and its operation in order to be able to use the IC. What must be understood is the correct terminal connection and biasing for the input terminal, as well as the limitations on supply voltages, signal levels, and external load. In the schematic diagram shown in Fig. 33.4 (a), the base leads of Q1 and Q2 are connected to the pins on the IC unit and serve as the two inputs of the op-amp. Q1 and Q2 transistors form a differential amplifier circuit. Transistors Q12 and Q13 constitute a complementary emitter follower output stage. The output is taken at the emitter of transistors Q12 and Q13. This push-pull configuration allows the op-amp to have a very low output impedance, which is analogous to a voltage source having a very small internal resistance.

CMRR of Op Amp Formula (Common Mode Rejection Ratio)

CMRR of Op Amp Formula (Common Mode Rejection Ratio):

A measure of this rejection of signals common to both inputs is referred to as the CMRR of Op Amp and a numerical value is assigned, which is called the common-mode rejection ratio (CMRR).

Op Amp Differential Amplifier Circuit Diagram and its Operation

Op Amp Differential Amplifier Circuit Diagram and its Operation: 

A circuit that amplifies the difference between two signals is called a difference or Op Amp Differential Amplifier.

Differential Amplifier with two Op Amps

Differential Amplifier with two Op Amps: 

The gain as well as input resistance of the differential amplifier can be increased by using two op-amps. The characteristics of such an amplifier are identical to those of a noninverting amplifier.

Differential Amplifier With Three OP Amp

Differential Amplifier With Three OP Amp: 

Differential Amplifier With Three OP Amp consists of two stages—one formed by op-amps A1 and A2 and second by op-amp A3.

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Differential Input and Differential Output Amplifier

Differential Input and Differential Output Amplifier: 

The differential input and differential output amplifier is widely employed as a pre-amplifier and in driving push-pull arrangements.