Voltage controlled oscillator and circuit

Voltage Controlled Oscillator

jojo July 29, 2018 7 Comments
VCO (Voltage controlled oscillator) Voltage controlled oscillator is a type of oscillator where the frequency of the output oscillations can be varied by varying the amplitude of an input voltage signal. Voltage controlled oscillators are commonly used in frequency (FM), pulse (PM) modulators and phase locked loops (PLL). Another application of the voltage controlled oscillator is the variable frequency signal generator itself. The block diagram of a typical voltage controlled oscillator is shown below. Voltage controlled oscillators can be...
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Function Generators

jojo August 13, 2017 14 Comments
All About Function Generators A function generator is a signal source that has the capability of producing different types of waveforms as its output signal. The most common output waveforms are sine-waves, triangular waves, square waves, and sawtooth waves. The frequencies of such waveforms may be adjusted from a fraction of a hertz to several hundred kHz. Actually, the function generators are very versatile instruments as they are capable of producing a wide variety of waveforms and frequencies. In...
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PUT Controlled Sawtooth Wave Generator

jojo February 25, 2010 No Comments
A PUT controlled sawtooth generator circuit is shown in figure. When power is first applied, the programmable unijunction transistor (PUT) is off. The capacitor C begins to charge up and the output voltage rises. This continues until the output voltage (which is also the PUT anode voltage) is about 0.7 V above the control input (the gate voltage). The PUT gets switched on. The capacitor C is shorted out through PUT and, therefore, capacitor gets immediately dis­charged through the...
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Sawtooth Wave Generator

jojo March 25, 2014 15 Comments
Sawtooth wave generator. Many people often get confused between sawtooth wave and a triangular wave. Sawtooth waveform is a type of linear non sinusoidal waveform with a triangular shape in which the rise time and fall time are different. A pure triangular waveform is is also linear, non sinusoidal and have a triangular shape but it has equal rise and fall times.The sawtooth waveform can also be called an assymmetric triangular wave. The graphical representation of a triangular and...
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Triangular waveform using Schmitt Trigger

jojo February 25, 2010 62 Comments
How to make a Triangular waveform using Schmitt Trigger and Integrator ? Another triangular-waveform generator that needs fewer components is shown in figure. The arrangement consists of a non-inverting Schmitt trigger Ax and an integrator A2. The output of a Schmitt trigger is a rectangular wave that drives an integrator. The output of the integrator is a triangular wave, which is fed back and used to drive the Schmitt trigger. Thus first stage drives the second, and the second...
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Triangular wave generator

Triangular Wave Generator

jojo August 28, 2018 11 Comments
Triangular wave generator using opamp This is an interesting project for newbies. This article is about creating a triangular wave generator using opamp IC. There are many methods for generating triangular waves but here we focus on the method using opamps. This circuit is based on the fact that a square wave on integration gives a triangular wave. What are Triangular waves? Triangular waves are a periodic, non-sinusoidal waveform with a triangular shape. People often get confused between the...
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Schmitt Trigger using Op-Amp

jojo August 13, 2017 12 Comments
Schmitt Trigger or Regenerative Comparator Circuit A Schmitt trigger circuit is also called a regenerative comparator circuit. The circuit is designed with a positive feedback and hence will have a regenerative action which will make the output switch levels. Also, the use of positive voltage feedback instead of a negative feedback, aids the feedback voltage to the input voltage, instead of opposing it. The use of a regenerative circuit is to remove the difficulties in a zero-crossing detector circuit...
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Pulse Generator using Op-Amp

jojo February 25, 2010 10 Comments
How to make a Monostable Multi Vibrator using 741 IC ? As already explained , a monostable multivibrator (MMV) has one stable state and one quasi-stable state. The circuit remains in its stable state till an external triggering pulse causes a transition to the quasi-stable state. The circuit comes back to its stable state after a time period T. Thus it generates a single output pulse in response to an input pulse and is referred to as a one-shot...
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Square Wave Generator using Op-Amp

jojo July 9, 2012 13 Comments
How to make an Astable or Free running Multi vibrator using 741 Op-Amp ? The non-sinusoidal waveform generators are also called relaxation oscillators. The op-amp relaxation oscillator shown in figure is a square wave generator. In general, square waves are relatively easy to produce. Like the UJT relaxation oscillator, the circuit’s frequency of oscillation is dependent on the charge and discharge of a capacitor C through feedback resistor R,. The “heart” of the oscillator is an inverting op-amp comparator The compa­rator...
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Zero Crossing Detector using IC 311

jojo February 25, 2014 3 Comments
How to make a Zero Crossing Detector using  311 Op-Amp IC ? A zero-crossing detector using IC 311 (8 pin DIP unit) is illustrated in figure. The positive (above 0 V) going input signal drives the output transistor on, the output going low (- 10 V in this connection). The negative (below 0 V) go­ing input drives the output transistor off, the output going high (+ 10 V in this connection). The output is thus an indication of whether...
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