Latching relay (CB25722E)

The figure shows how to connect a relay to obtain the latch effect. The circuit is from an Electronics Now from June 1994.

Lights On Reminder (CB10425E)
This circuit was obtained in a 1978 magazine, but it can be easily assembled. What the circuit does...
Intercom using old phones (CB20676E)
With this circuit it is possible to use a pair of old telephones in a wired communication system. The...
Remote control transmitter (CB23712E)
This remote-control transmitter for the 27 MHz band was found in the November 1960 Radio...