This circuit was obtained from an American 1980s documentation. The frequency depends on the crystal and the circuit may be a PNP that reaches the generated frequency.
Found in a1968’s Burr Brown documentation, this shield uses an integrated circuit from that time,...
This amplifier, to detect biological signals in implanted transmitters, uses transistors such as...
This General Electric circuit was found in a 1964 documentation. The circuit triggers a relay when...