Variable high-current resistor, in particular for use as a protective element in the power switching art, and a circuit with the use of the high-current resistor

摘要

A changeable high-current resistor for use as a protective component in power switching technology has already been proposed, containing carbon as the resistor material, in which there is a boundary area with a transition region to another electrical conductor. If pressure is applied, the resistor can be kept low-ohmic in the transition region. In the present state of the art of the heat generated by the current in the resistor is transferred to the high-ohmic state. According to the invention, the pressure on the changeable high-current resistor can be suitable affected. The carbon and/or soot-containing layer (11) can be pressed by the force with a predetermined first degree of pressure on the other conductor (12, 13) to set the low-ohmic state of the resistor and, in short-circuit conditions, the pressure can be reduced within a sufficiently short time to a second degree at which the resistance in the transition region (15) increases by at least two orders of magnitude. Such high-current resistors (10) may be used in conjunction with power switches, power semiconductors, contactors and vacuum switches.