racing car control

In most cases the current for a racing track is supplied by a mains voltage unit fitted with a three-position switch, with which the maximum voltage, and hence the maximum speed of the car can be adjusted. Although it is likely that in practice only the fastest position will be used, it is in view of the younger racers that the circuit is so designed that (by means of a potentiometer) it can be used with all positions of the switch on the supply unit.