This circuit was found in a 1967 Delco Radio documentation. The circuit has an input voltage of 250 V and the load current is 2 A. The transistors used are from that time.
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....