This circuit can modulate a laser rate at frequencies of 50 kHz. We found the old documentation. The bipolar transistors can be the BD135 and 136 and the FET admits equivalent.
This circuit is from an English publication from 1978, but it can be assembled with BC548 for TR2...
This simple voltage regulator with FET was found in American documentation from the 1980s....
This circuit was used to regulate the speed of small DC motors of cassette recorders. However, if the...