This circuit was found in a National Semiconductor manual from the 1980s. The operational amplifier is from that time and the waveforms are shown in the diagram.
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...