This tube circuit was found in the magazine 73 for radio amateurs in an issue from the 1980s. Note the transformer used to power the circuit.
This basic oscillator with tunnel diode generates a 100 kHz signal with 1 uW output power. The...
This amplifier for medium or high impedance magnetic headsets (above 200 ohms) was found in an...
This circuit provides precise signals of three frequencies, using CMOS technology. The integrated...