3-tube receiver (T1602E)

Found in a 1949 Radio Electronics, this circuit employs vacuum tubes of the time. Power supply not provided.

Headphone Extensions (CB23790E)
The figure shows three circuits for using headphones in amplifiers with speakers that do not have...
Nicad charger (CB9540E)
In this charger, the charging current is basically limited by the LEDs. The transformer is a low...
Fast Voltage Follower (CB4904E)
This configuration is from an old integrated circuit manual. The circuit can be applied to modern...