How voltage follower works
Connecting the output directly to the inverting input makes a unity-gain buffer. An ideal buffer draws no input current, so source resistance does not create an input drop. It supplies the load current from its power rails. Without the buffer, the source and load resistances form a voltage divider.
Ideal DC equations assume negative feedback and operation within the supply rails. The guest uses a generic op-amp model; finite gain, input loading, output current and saturation can change the simulated result.
Change the form inputs or click a component value on the schematic. Choose Try in CircuitSim to simulate the configured circuit.