Single-supply op-amp, rails and all

by ourcircuits

9 parts

One 9 V rail and no negative supply: a 100 k/100 k divider parks the non-inverting input at half the rail, and the 1 µF coupling cap lets the signal ride on top of that bias while the 10 µF cap grounds the gain-set leg only for AC. The 5-pin op-amp cannot drive its output past the voltages actually solved at its V+ and V− pins, so an 11× demand on a ±0.5 V input runs straight into both of them and the output clips flat at 9.0000 V and at 0 V. The op-amp is a macromodel — a tanh-limited controlled source whose swing is read live from the rail nodes each step — with open-loop gain set to 1000 here; bandwidth, slew rate and output-current limit are not simulated.