This amplifier with fixed AC bias was found in a 1947 documentation. The circuit uses two transformers in the power supply and two full-wave rectifier tubes.
This circuit is suggested by General Electric in 1966 documentation. The Triac must match the...
This circuit was suggested by Popular Elecronics from the 90's. The circuit has high input...
This circuit is nothing more than a turn signal for two alternating LEDs that can decorate a robot...