This circuit for light modulated in frequency (FM) operating at 50 kHz was found in a 90’s Electronics Now. The circuit has an active filter. Modern equivalent transistors can be used.
Based on Allegro's A6275, this circuit controls the brightness of various displays. The circuit is valid...
This small transmitter can act as a wireless microphone operating in the medium wave range,...
This is the circuit of an RCA Dimmer sold in 1967. With it it is possible to control a load up to...