SOND FOR AUTOMATISK PAVERKNING AV EN REGLERKRETS FOR EN ANTIIMKRETS

摘要

The glass pane of a vehicle window is provided on the surface of its central viewing area with a plurality of spaced, parallel linear heating resistors. First and second buses, disposed laterally of the central viewing area, extend transversely of the resistors and supply electric power to the resistors. A miniature transistorized control circuit mounted at a corner of the pane away from the central viewing area controls the supply of power to the buses. A plurality of moisture sensing, electrically conductive probes are provided on the pane at widely spaced zones and are connected to the input terminal means of the control circuit. Each probe includes a first portion coextensive in length with a resistor and running parallel thereto. One of the probes has a second portion parallel to and closely spaced from one of the buses. The control circuit responds to detection of fogging of the pane by anyone of the probes.