Thermostatic relay (CB21285E)

We found this circuit in an old QST magazine. The circuit is powered according to the thermostatic relay used.

Balance Control (CB6310E)
This balance control for the channels of a stereo system was found in a 1969 Mullard...
Electronic Bongos (CB23959E)
The article that teaches the assembly is from a Radio Electronics issue from July 1969. The...
Undervoltage alarm (CB22186E)
Found in old English documentation, this circuit is still current. The circuit trips with a sound...