Two-tube regenerative receiver (T1595E)

This circuit is from a Radio Electronics from 1949. The circuit is battery powered and has high impedance listening.

Rain Alarm (CB15108E)
This alarm, from a 1996 magazine, can be fitted with two BC548s in the original configuration...
Simple touch switch (CB9563E)
Using only one general purpose transistor this circuit is powered by batteries. The lamp of the...
Programmable attenuator (CB9031E)
Can be used as a shield, this old American documentation circuit offers digitally selected...