This circuit is from an old American publication, using transistors of the time and operating with a 48 V power source. The load is 2.2 ohm, and the transistors must be replaced by modern equivalents.
With this circuit it is possible to vary the resistance by adjusting the mark/space reaction of...
This circuit is from a 1967 US publication. The configuration can serve as a basis for designs...
This analog TV circuit can be used on a small transmitter. The circuit is from an 80's American...