This circuit is from a 1997 publication, but it can be assembled with a BD136 for TR1. The resistor R11 cut when scanning the circuit is 680-ohm. The circuit uses a moving point indicator to drive external loads with different voltages applied by a keyboard. The supply can be done with voltages of 6 V applied in the line of pin 3 of the CI. The power supply does not have to be symmetrical.
