Op-Amp Integrator Simulation help needed

Thread Starter

mishra87

Joined Jan 17, 2016
741
Hi Guys,
please find attached LT Spice find.
I wanted to get triangular wave from 5V peak to peak (-2.5V to +2.5V) rectangular input signal with 50us high and low pulse
As per my theoretical analysis triangular wave should start from 0V to -2.5V and -2.5 to 0V , (Negative integrator).

Could anybody help me to get the results.

Regards
 

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crutschow

Joined Mar 14, 2008
24,927
Below is the simulation of your circuit, slightly modified.
I added an input DC block capacitor so that the average input is always 0Vdc, to avoid output offset from that, and lowered the value of R2 to reduce the start-up settling time.

1588357079446.png
 

Audioguru again

Joined Oct 21, 2019
1,467
I am surprised that the simulation did not use an impossible opamp with no input offset voltage.
I didn't look but maybe because the input transistor in the opamp are bipolar with some input bias current.
 

Thread Starter

mishra87

Joined Jan 17, 2016
741
Below is the simulation of your circuit, slightly modified.
I added an input DC block capacitor so that the average input is always 0Vdc, to avoid output offset from that, and lowered the value of R2 to reduce the start-up settling time.

View attachment 205907
Hi,
Thanks for your support.
I studied in some book as per below and i wanted to do the simulation but i did not see the same results in any of above simulation.
Could anyone please guide me here to get the results as per below.
1588436855529.png

Thanks in advance !!!
 
Last edited:

Thread Starter

mishra87

Joined Jan 17, 2016
741
Try this sim. I suspect a real-world circuit won't give the same results, because of input bias tolerances and non-rail-to-rail output of the op-amp.
Hi Alec_t,

Thanks for you support,
Yes, it worked as expected.

Thank you very much again !!!
 
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