This circuit was found in a Motorola manual from 1968. As it can be obtained 20 V at 15 kHz from 120 V x 60 Hz. The components are of the time.
This circuit is from an Electronics Now from August 1995. The triac is according to the load that...
Although it was found in a British magazine 1976, this circuit can be easily upgraded with the...
This circuit was found in the January 1992 issue of Radio Electronics magazine. The capacitor...