| 摘要 |
PURPOSE: To prevent malfunction due to electrical short-circuit or the like and resulting accident even if splashes of water occurs, by forming on the surface of an insulating board conductive patterns composed of a pair of electrodes with such an interval that a splash of water allows the passage of electric current, and stopping power feed to the side to be supplied with electric power according to the electrical connection between the electrodes. CONSTITUTION: A pair of electrodes 32 for water splash detection are formed on a control board 30; the electrode B 32b, one of the pair is a conductive pattern 31 of an arc, approx. 5mm in diameter, and the electrode A 32a, the other of the pair, is a small circular conductive pattern formed at the center of the arc. The board 30 is provided under a heating apparatus horizontally with the conductive pattern 31 facing upward. If water or the like wets the surface of the control board 30 and conduction is provided between the electrode A 32a and the electrode B 32b, the electrode A 32a that has been at the high level is brought into the ground level like the electrode B 32b. A microcomputer detects that and stops power feed to the PTC heater as well. This prevents accidents due to splashes of water and assures safety. |
