Door buzzer or alarm (CB20492E)

This solar powered circuit was found in a 1991 documentation. The transistor is a general purpose NPN.

Intermittent buzzer (CB20494E)
This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...
Fuzz Distortion Pedal (CB11247E)
This well-known configuration of the guitar effects pedal was obtained in an English magazine from...
Complementary Mini Amplifier (CB970E)
This simple circuit was found in the Spanish magazine “Todo Electronica”, in an edition of 1996....