Third Order Low Pass Filter (CB25264E)

This circuit was found in the December 1990 issue of Radio Electronics magazine. It was used in a home theater sound system.

Sensitive Photo Relay (CB894E)
This photo-relay uses a Darlington stage to increase sensivity. Any photo-transistor can be used....
Operational Fuzz (CB11029E)
This circuit was obtained from Hands-On Electronics, an American magazine of January 1987. The...
Plasma Lamp with Triac (CB26134E)
We found this circuit in a Radio Electronics Experimenter from 1990. The circuit uses a common...