POSITIVE TEMPERATURE COEFFICIENT (PTC) RESISTANCE ELEMENT FOR USE IN A TONE GENERATOR

摘要

The specification describes a positive temperature coefficient (PTC) resistance element for a seat-belt monitoring system for an automobile that is adapted to provide timed audible and visual signals when operation of the automobile is initiated without the seat-belt being properly buckled. The resistance element is characterized by a body of PTC material having an anomoly temperature. The body has electrically conductive contact surface layers on different discrete surfaces of the body. One of the conductive surface layers is adapted to be conducted to a source of electrical power. The other conductive surface layer defines first, second and third contact areas which are electrically isolated from each other.