Circuit arrangement for a heating device which is heated by a PTC thermistor as a heating element, as a display of its heating state

摘要

In order to display the heating state of a heating device which is heated by a PTC thermistor (R1) as the heating element, a PTC thermistor (R2) is connected in the circuit arrangement as a comparator element, in parallel with the PTC thermistor (R1) and the voltage source (U). Each of these PTC thermistors (R1, R2) in each case has a fixed resistor (R3, R4) connected in series with it upstream. An evaluation circuit (4) and a display element (5) are provided in the bridge diagonal (3). <IMAGE>