This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is intend to receive MW station and the transistors are germanium types not easy to find today.
This circuit is from an English magazine from 1980, but it can be easily assembled with more...
Found in Philips' 1968 documentation, this circuit serves as a 6.3 V reference for high stability. |...
In critical applications of the RS-232 interface, the danger of induced voltages in the cables must...