This special effect doorbell circuit was found in the January 1984 issue of Radio Electronics magazine. The components are quite common and transistors such as the BC548 and BC558 can be used.
Found in a 1969 Electronics World, this circuit is intended for amplifying analog cable TV...
Place the lamp on the ignition threshold via R2. Your approach causes it to light up. The secret is...
This circuit has a voltage gain of approximately 100 times and can operate with medium and high...