Overvoltage protection device for control circuits using power transistors.

摘要

A protection device for circuits comprising at least one power transistor, for example PMOS or NMOS transistor,for controlling by modulation the speed of a direct current motor fed from the electricity mains through a rectifier, characterised in that at least one varistor (10) is provided in parallel with the input of the rectifier (3) and at least one varistor (11) is provided in parallel with the power transistor.