Protection device for electrical circuit, has limitation unit comprising field-effect transistor to increase voltage drop when current exceeds limitation value, and actuating unit supplied from voltage drop in limitation unit

摘要

The device (1) has a limitation unit (5) for limiting current circulation in an electric circuit (3). A mechanical contact switch (7) is assembled in the circuit to open or close the circuit. An actuating unit (9) of the switch is connected at terminals of the limitation unit to open the switch when current exceeds a limitation value. The limitation unit comprises a field-effect transistor to increase the voltage drop when the current exceeds the limitation value, and the actuating unit is supplied from the voltage drop in the limitation unit.