Unijunction metronome (CB21701E)

This traditional metronome circuit is powered by voltages from 9 to 12 V and output drives a common speaker.

Light Relay (CB19976E)
This circuit activates a relay when the sensor receives light. The sensor can be any common LDR,...
0 to 20 V x 1 A Power Supply (CB1186E)
We found this circuit in a 1980 documentation. With basic changes, including transistors that were...
Wind Detector (CB5155E)
When a small air current reaches the piezoelectric sensor, a small audio signal is generated and...