Circuit Simulator Java Applet

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Circuit Simulator is produced by Paul Falstad, and is available from .

Circuit Operation

The op-amp compares the voltages applied to the inverting and non-inverting inputs, producing one of two fixed output levels depending on which input is larger. The output swings towards the positive supply rail if the non-inverting input is larger, or towards the negative supply rail if the inverting input is largest.

Please see the op-amp comparator topic for more details.


  1. Adjust the sliders at the right hand side to vary the inputs and observe the output voltage if the upper (non-inverting) input is greater than, equal to, or less than the lower (inverting) input.

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