Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by modern equivalents. The circuit is for resistive loads.
This power supply, found in an Argentine publication from the 1970s, uses a wire potentiometer of 25 W or more...
This circuit was obtained from an English magazine from 1979, but can be easily assembled today...
The oscillator shown in the figure generates a 1 kHz tone that is reproduced on the speaker with...