This circuit produces a signal that has the waveform of the sound produced by or near the banjo. The circuit is from an 80's American documentation. The signal must come from an ordinary guitar.
This receiver with two common JFETs was found in an old English documentation. The phone is...
This TTL circuit with the 7493 makes the binary count of the pulses sent by a flip-flop with the...
This circuit was found in a Popular Electronics from the 90s. The counter circuit is not common...