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For my homework, we are supposed to simulate an inverting and noninverting amplifier using a single supply and the LM324 opamp. I built the inverting amplifier using a voltage divider, but my output voltage is not a sinusoidal wave rather a square wave that has a cutoff. The output signal should be amplified sinusoidal wave. so, how can I fix this?

Heres the schematic of the circuit: enter image description here

Here are the screenshots of the results enter image description here

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Two problems; firstly you need to AC couple the 2.5 Vrms signal to the 470 ohm resistor (R1) or you inevitably are trying to force the op-amp to produce an output voltage that is highly offset from mid-rail: -

enter image description here

If you can't AC couple, you should bias the 2.5 Vrms signal so that it has the same DC level as the node of R3 and R4. Maybe by doing this: -

enter image description here

The 2nd problem is that 2.5 Vrms is 7.071 volts RMS and, with an amplifier gain magnitude of approximately 20 (R2/R1) the op-amp will try and produce an output level of 141.4 volts p-p. That of course is impossible for the LM324 or any op-amp on the limited power supply voltage of 9 volts.

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  • \$\begingroup\$ Other than decreasing the R2 and R1 ratio, Is there a way I can fix the 2nd issue, or is that an issue that exists in the simulation but not in the real world? \$\endgroup\$
    – Mohit Singh
    Commented Oct 29, 2020 at 1:22
  • \$\begingroup\$ You can't expect an op-amp to produce an output signal in peak-to-peak values that is close to or bigger than the voltage difference between its power rails @MohitSingh \$\endgroup\$
    – Andy aka
    Commented Oct 29, 2020 at 9:05
  • \$\begingroup\$ What you should consider doing next if you are done with this question and answer. If you need clarification, add a comment. \$\endgroup\$
    – Andy aka
    Commented Oct 29, 2020 at 10:27

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