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 power supply, found in an Argentine publication from the 1970s, uses a wire potentiometer of 25 W or more...
This circuit was obtained from an English magazine from 1979, but can be easily assembled today...
The oscillator shown in the figure generates a 1 kHz tone that is reproduced on the speaker with...