Hi I constructed a circuit to create a 1Hz square wave with LM741 Opamp. The first part makes that and it makes it perfectly.
But I need to convert it to a 8Vpp triangular wave. Without any offset, I simulated the circuit below in LTSpice it was flawless. But in real life I got some weird offset from the output of the triangular wave converter.
Figure I implemented, first part creates 1Hz 21 Vpp zero offset square wave,2nd part convert this into a triangular wave with 8Vpp:
In real life it has 8.2 Vpp which is very good for me but it starts from -6 to +2 (it has -2 V offset)
How can I get rid off this offset?
Better one:
Best Answer
That's the classic problem you get when trying to drive an integrator from a square wave.
The integrator's output will drift towards one supply or the other and may eventually saturate because:-
1) Square wave is not perfectly symmetrical (square). The saturation limits for the square wave generator are not symmetrical.
2) The integrator op amp has input offset voltage and input bias currents.
You can't use a polarised cap because it is being to charged to both polarities. Use a non-polarised cap or keep cap value lower and use a non-electrolytic.
Below is a favoured way of generating a triangle wave. It uses a non-inverting schmitt trigger driving an integrator.
Triangle wave output amplitude is set by ratio of R1 to R2.
Frequency is set by R3*C1 time constant.