A Simple Function Generator

Simple triangle-wave generators have a weak point in that the waveform of their output signal normally cannot be modified. The circuit presented here makes it possible to easyly alter the waveform of a linearly rising and steeply trailing saw-tooth sign via a symmetrical triangle-wave to a slowly trailing, steeply rising linear sawtooth. The wanted waveform could additionally be selected impartially of the frequency, which can additionally be varied uniformly from zero.2 Hz to eight kHz. At the same time, an oblong signal with variable responsibility cycle (also unbiased of frequency) is on hand at the rectangular-signal output of the circuit.

 
The circuit consists of integrator IC1b, whose output is applied to comparator IC1c. The output of the comparator is a rectangular signal The output of IC1b is raised through amplifier IC1d to a level that enables the full output voltage vary of the operational amplifier for use. Op amp IC1a provides a secure virtual earth, whose stage is set to 1 of 2 the availability voltage with P1. The easy surroundings of the frequency is made that which you can imagine by means of comments of part of the output of the comparator to the input of the integrator by approach of P2. This preset is regularly now not equipped in usual triangle-wave turbines. Network D1-R1-D2-R2-P3 makes it possible to provide integrator capacitor C3 completely different charging and discharge times.

This association enables the output sign at A1 and the accountability cycle of the rectangular wave signal at A2 to be various. Varying the amplification factor with P5 has no impact on the frequency set with P2. The slope of the signal aspects, the transient responses, and the output voltage range (rail-to-rail or with some voltage drop) depend upon the variety of op amp used. The TL084 used in the prototype offers a just right compromise between worth and assembly the wanted parameters. The circuit is highest constructed on a small piece of prototyping board. The circuit draws a present of no longer more than 12 mA.

Brief parameters:

Provides triangle-wave, sawtooth or rectangular signal
Waveform variable impartially of frequency (triangle wave and sawtooth)
Duty cycle of rectangular sign will be set independently of frequency

Applications:

Test and dimension
Pulse-width control
Summary of preset action:
P1 – units digital earth to a degree equal to Ucc/2;
P2 – units the frequency;
P3– units the waveform;
P4 – units the hysteresis of the comparator (frequency and amplitude of the triangle-wave sign)
P5 – sets the amplification of the triangle-wave and sawtooth alerts.