Water-Activated Triac Switch (CB24054E)

This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V power source must be isolated from the mains.

| Clique na imagem para ampliar |

Differential voltmeter with FETs (CB23655E)
This circuit was found in a Radio Electronics from May 1965. FETs are from the time, but the...
Sawtooth generator (CB8884E)
This circuit can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...
2-Tone Siren (CB18189E)
Because it uses TTL integrated circuits, this siren must be powered by 5 V or as indicated with D1 to...