Op-amp tester created from IMSAI Guy's design (https://www.youtube.com/watch?v=3iTyC4anucY&t=119s). Circuit comprises an Op-amp based dual rail supply, a 4hz square wave oscillator fed into DUT's. This one can only do 1 device at a time - a dual op-amp or a quad op-amp with the same pin outs as an LM358 (dual) or LM324 (quad). My DC supply is limited to 30v so can only deliver +/-15v to the op-amps under test.