Found in a 1924 documentation, this circuit is powered by 3 batteries, two of which are high voltage. The output is a high impedance headphone jack.
This circuit can control the power from 0 to 70% of the maximum power on a load. The circuit was...
This circuit is from a Radio Electronics from October 1970. The circuit uses transistors from that...
This tone control was obtained from the CA3140 datasheet, originally created by RCA. The CA3140...