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 experimental amplifier was found in the 1960 Mullard transistor reference manual. The...
This circuit from Motorola is from 1968, appearing elsewhere on this site. The transistors admit...
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...