The operational amplifier–the “op-amp”–was created to do by analog means what we now do digitally: to add, subtract, divide, multiply, integrate, and differentiate. In application, though, op-amps have long been used for so-much more. Fairchild Semiconductor (now part of onsemi) introduced the μA741 in 1968. It (and subsequent versions produced by other manufacturers) quickly became one of the most widely-used ICs in electronics.

This discrete-component version of the venerable 741 may seem only a curiosity, but it is a fully-functional op-amp following the original circuit as published by Fairchild. For amateur-radio work, it can be used, among other things, as part of a mic or audio-output circuit or to amplify and scale DC voltages in AGC or S-meter circuitry. It's designed for 2N3904 and 2N3906 transistors. Bare PCB only. Components not included.