This circuit was obtained in a French documentation from 1981 and can be easily assembled. The analog instrument itself can be replaced by the current scale of an ordinary multimeter.
This is stage is transformer coupled and was found in na old publication of the year 1958. The...
This configuration of PWM control with the LM317 was found in a Popular Electronics from the 90s....
The critical components for this 1970s project are transformers. The original transistors are made...