This passive loudness control was obtained in an old publication. The critical component is the tapped potentiometer that can be adapted with an external resistor network.
When two pulses reach the inputs of the circuit simultaneously, the PUTs fire triggering the lamp...
Using a DAC038 IC this circuit is from Radio Electronics from May 1983. The circuit must be...
This well-crafted source with current and voltage regulation was found in American documentation from the...