This is an improved circuit from the earlier version also found in the April 1972 Radio Electronics magazine. The power transistors must be provided with heat sinks.
In the figure we have an improved method of varying the voltage of a 7812 regulator. The circuit is...
This 5-range current measurement circuit was found in the September 1989 issue of Radio...
Found in an old English publication this circuit uses a dual gate MOSFET. Coils not specified....