This low frequency divider uses unijunction transistors. The bipolar transistor can be a BC548 and the zener diode Z4XL can be a 12 V zener. The circuit was found in a 1967 publication.
This circuit came out in an American magazine that no longer exists. It's the Electronic...
This circuit originally came out in a Budget Electronics from 1981. The American magazine no...
This is the traditional audio preamp configuration with the National Semiconductor LM382. The...