This circuit is from a Popular Electronics from the 90s, consisting of a repeater relay for remote control of TV, which today can be done by Wi-Fi or other simpler resources.
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...