Two-tone solar buzzer (CB20493E)

This circuit was found in a 1991 publication. The transistor can be a general-purpose type.

Touch Switch (CB12007E)
A touch of the sensor makes the load bistable (load) connected in Q1. For a BC548, a 6 V or 12 V...
Asymmetric Astable 4093 (CB16089E)
With the use of an additional diode and a resistor, the configuration of the figure can be...
Proximity sensor (CB9570E)
This circuit was found in documentation from the 1980s. The circuit uses several components of the...