How do i get trapezoidal wave at frequency 20Hz by using square wave and LM741 Op-Amp?
can you please explain in details to get it with saturation concept?

 

Lots of ways to skin the cat. One method would be to pass the square wave through another op-amp circuit, an integrator, to produce a triangle wave. Then pass that triangle waveform through a standard amplifier circuit to clip the peaks. Adjust the gain to clip at the desired level and produce the trapezoid of your choice.

Or, instead of op-amp circuits to make a square wave and then a triangle, you could use the voltage on the timing capacitor of a 555 timer circuit to give you a waveform that resembles a triangle. It's not precisely a triangle because it's the voltage of a charging/discharging RC tank, but it's very close for many applications.

 

Do you want Tri symmetrical about ground or offset ?

Is square wave symmetrical with respect to ground or offset ? Vmin,
Vmax.

Just 20 Hz, frequency does not change ?

Power supply to power circuits, what is its voltage(s) ?


Basic approach -



Regards, Dana.