This switching buck regulator with the NE5560 was found in the February 1980 issue of Radio Electronics magazine. The power transistor must be provided with a heat sink.
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....