I made a miller integrator with a dc offset. (The initial condition of the capacitor is set to zero so initial condition is not the problem). There is a capacitor or 10-7 F capacitance and a source resistance of 10K ohms. Due to the dc offset of 0.002 V, the integrator should cause the output signals to be like a ramp and eventually saturate when the 12 v saturation limit is reached. When I make this circuit in multisim online, the output is instantly -12.something. And it is a constant signal. why am I not getting a ramp towards saturation? Here is the circuit:
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1\$\begingroup\$ Possible duplicate of dc offset in a miller integrator \$\endgroup\$– Eugene Sh.Commented May 5, 2017 at 21:34
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\$\begingroup\$ No question is different. About the same circuit but different. \$\endgroup\$– Moeen AhmedCommented May 5, 2017 at 21:40
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\$\begingroup\$ OK, will take your word and retract the vote.. \$\endgroup\$– Eugene Sh.Commented May 5, 2017 at 21:42
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1 Answer
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Your circuit will integrate the offset voltage in the same way as any other input signal and do what you expect.
You will need to setup your simulation to include the startup otherwise it will delay until the system operating point is stable before starting the simulation.
There is probably a configuration of Multisim to do that.
One way to sidestep this is to put a switch across the capacitor that is opened at a specified time into the simulation (for example 1 millisecond).
answered May 5, 2017 at 22:35