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 two-station intercom was found in documentation from 1966. R4 should be experimentally...
This circuit was found in a 1978 publication. Equivalent operational amplifiers can be used. The...
This circuit was found in a RCA documentation from 1977. The integrated circuit is uncommon today. It is...