This audio mixer was found in an old American documentation. The potentiometers are 1M and the input capacitors are 100 nF. The circuit requires power supply voltages from12 to 18 V.
This circuit, from a 1973 publication, locks the relay when the light that falls on the LDR is cut...
Found in the December 1986 issue of Radio Electronics magazine, this circuit is designed to select 4...
This typical two-transformer push-pull step circuit can be found on many small old radios and...