The figure shows a typical circuit of a variac with a special transformer with sliding adjustment of the winding turns. The circuit is from an Electronics Now magazine from December 1997.
This circuit is part of an article published in the March 1990 issue of Radio Electronics...
Found in an American publication from 1968, this circuit aims to keep the torque of a DC motor...
In the figure we have the typical circuit of a Baxandall tone control applied to an operational...