Found in a 1924 book by Gernsback, this circuit uses a double variable capacitor, a component not very common at the time. Listening was done on a loudspeaker at the time.
The circuit is from a Radio Electronics magazine from October 1987. The Triac must be equipped with a...
The integrated circuit used is not common today and the voltage gain is unitary. The circuit is...
This source with two symmetrical output voltages was found in 90s Radio Electronics. The 22 V...