6AC7 Amplifier (T450E)

Obtained in MIT documentation, this 4-stage circuit has high gain for small signals. The power supply sources 150 V.

Lock Timer (CB5980E)
It is like to the previous circuit with a lock that keeps the LED on at the end of the timer. The...
Commercial Radio SRF25 (CB18401E)
This 6-transistor Japanese radio from the 1960s used germanium transistors and had an output power...
Sewing Machine Motor Control (CB25103E)
This simple SCR control was found in the December 1987 issue of Radio Electronics magazine. The...