delabs circuits
delabs circuits

delabs circuits

Electronic Engineering Schematics

Home - Circuits - Analog - Opamps - Triangle Oscillator

Square and Triangle Op-Amp Oscillator

Here is the circuit of a Op-Amp based Square Wave Generator. One of the main application of this is in a Simple PWM circuit and Triangle Opamp Oscillator. The Slope of the Triangle wave is compared with a DC Level to derive a pulse width or On-Time proportional to a Voltage. 

The Philbrick Archive and Operational Amplifier

This On-Time proportional to voltage is for a fixed oscillation rate based on C2-C3 and R15. The C2-C3 form a Unpolarized cap, This type is also used in crossover networks in speaker boxes. This is because, a plastic 4.7 uF (2 * 10uF series) is big and costlier, but a plastic cap is very stable and closer to an ideal cap.

First you need to know that most opamps in such circuits can give a square wave, but very few can swing to the rails (+/-5). For designing take 75% of Vcc. CA3130 is one that can swing to rails like a CMOS gate.

Active Filter Design with OpAmps

Assuming the swing of output is around +/- 4V, the pin 10 + input will be at +/- 2V. When the cap is discharged at 0 V, let us take that the output is +, the cap charges to a little above +2, - input becomes dominant, so output swings negative. This discharges the cap to 0 and then charges it negatively upto -2. This in turn flips the output to + as pin 10 turns dominant. Hence this continues as a oscillation, with a nice triangle across the cap for the PWM comparator.

Dominant means more +, 0 is positive compared to -2V. Also -2.5 is negative compared to -2.2.

Square and Triangle
            Op-Amp Oscillator


Generic Circuit Diagram of a Op-Amp based Square Wave Generator. Use it as a Simple PWM circuit or Triangle Opamp Oscillator.Used in A to D Convertors, Switchers and Communications .

Read More

Wide-Bandwidth Dual JFET Opamp LF353

"These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage."

Back to Analog Op-Amp Circuits

...


...

...


...

...


delabs Technologies

20th Mar 2020




...

Disclaimer and Terms of usage

The documents, software, tools and links are provided to enhance the ability of an electronics student, hobbyist or professional by sharing information. The information, links etc. should be used by the website visitor, at his or her own risk and responsibility. There may be concept, design and link errors in the pages.

Creative Work, ideas and documents of delabs can be used for Product Design and Development by R&D Engineers, Hobbyists, Students and even firms for creating useful products. These cannot be used for reprint, replication or publishing online or offline.