Device with PTC heating cable comprising a current limiting device

摘要

The heating device has a heating cable (7) with a positive temperature coefficient (PTC) and a current limitation device for limiting a current crossing the PTC cable. The limitation device has a resistive unit (6) with a negative temperature coefficient (NTC) mounted in series with the heating cable (7). The NTC unit is chosen such that its resistance is negligible when PTC cable has reached its stable mode.