Astable 555 (CB21101E)

This 50% duty cycle configuration was found in a Popular Electronics from the 1990s. The operating frequency is given by C1.

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...