Found in a 1967 Electronics World, this preamplifier uses an integrated circuit from that time, difficult to obtain today. The maximum frequency is 15 kHz.
This circuit uses old germanium transistors because it was found in an old magazine from 1973....
This digital circuit is from a Radio Electronics magazine from December 1991. It does not use a...
Found in a 1990s Motorola documentation, this circuit aims to protect a triac that drives an...