This circuit was found in an American documentation from the 80's. The components are from that time. It provides a variable output of 18 to 30 V with a current of 200 mA.
This circuit, suggested by Siemens, allows the activation of 24 V solenoids from TTL LSL signals,...
In the figure we have the way to linearize the response of a TTL port with the use of a feedback...
In the figure we have the original version of an amplifier with high input impedance, 1.2 M ohms....