Electronic Circuits and Diagram-Electronics Projects and Design

RELATED ARTICLE SWEEP-FREQUENCY GENERATOR In most cases, the frequency of an oscillator is determined by the time constant RC. However, in cases or applications such as FM, tone generators, and frequency-shift keying (FSK), the frequency is to be controlled by means of an input voltage, called the control voltage. This can be achieved in a voltage-controlled oscillator (VCO). A VCO is a circuit that provides an oscillating output signal (typically of square-wave or triangular waveform) whose frequency can be adjusted over a range by a dc voltage. An example of a VCO is the 566 IC unit, that provides simultaneously…

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 fact, each of the waveform they generate are particularly suitable for a different group of applications. The uses of sinusoidal outputs and square-wave outputs have…

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 PUT. The output voltage, which is equal to the voltage across the capacitor, falls. When the current through the PUT falls…

How to make a Sawtooth Wave Generator using Op-Amp 741 IC ? Sometimes it is felt necessary to provide a relatively slow linear ramp with a rapid fall (or rise in the case of a negative ramp) at its end. This is a sawtooth wave. Also, in applications such as time base generators and power control circuits, the sawtooth must be triggered by (or be synchronized with) some control signal. The difference between the triangular and sawtooth waveforms is that in triangular waves the rise time is always equal to its fall time while the sawtooth waveforms have different rise…

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 drives the first. But the question arises on how the circuit gets started in the first place. This is explained below….

A simple sawtooth generator using a GTO and a Zener diode is shown in figure. When the supply is switched on, the GTO will turn on, resulting in the short-circuit equivalent from anode to cathode. As a consequence the capacitor C will begin to charge toward the supply voltage, as illustrated in figure. As the voltage across the capacitor C exceeds the Zener potential, there will be a reversal in gate-to-cathode voltage resulting in a reversal of gate current. Eventually, the negative gate current will be large enough to turn the GTO off. Now the capacitor C will begin to…