This is the typical audio amplifier for a 1967 television. We found it in a magazine from the time. Note the use of the output transformer and the high supply voltage. The circuit is an RCA CTC21.
This circuit produces a signal that has the waveform of the sound produced by or near the banjo....
This is a circuit with a period component that consisted of a voltage reference. The circuit is...
This circuit doubles the frequency of a rectangular signal applied to its input. The circuit has a...