Capacitive Relay (T1527E)

Found in Popular Electronics from August 1956 this sensitive two-tube relay is powered directly from the mains power supply.

60 Hz pulses with the MM5369 (CB24930E)
The figure shows how to generate a 60 Hz clock signal for TTL circuits. The circuit is from Radio...
Instrumentation amplifier (CB23846E)
This circuit for an isolated instrument or multimeter can increase the sensitivity of your...
CMOS Astable Multi Tone (CB10723E)
Although it is a common configuration today, this circuit was taken from an old publication. The...