The capacitor used in this circuit can have values between 5 and 30 uF. The circuit is of old documentation for radio amateurs. Observe the special source used in the supply.
This simple circuit was found in an English magazine that no longer exists, January 1970 issue. It is...
This circuit, suggested by a 1975 documentation, detects an electrical discharge in a storm by...
This circuit for timing small loads was found in a 1964 General Electric documentation....