Abstract: A passaged PTC heater is electroded by hot aluminum spraying. A hot alkaline solution is used to dissolve and remove undesired aluminum that may be coated on the passage walls. However, prior thereto, the aluminum electrode coating is covered with a protective solvent-removable alkaline-resistant resist ink.

Abstract: An electroceramic device formed of a body of electroceramic material and a process of making the device is disclosed. The body has an outer perimeter edge and two sides, each of the sides forming an exterior face. At least one groove is disposed on one of the exterior faces of the body, the groove extending from the edge and forming an opening on the exterior face. A lead wire is disposed in the groove and extends outwardly from the body through the edge. A metallized, electrically conductive coating is disposed on each of the exterior faces, and are electrically insulated from each other. The coating fills any voids left between the lead wire and the interior of the groove, whereby to hold the lead wires in place within the groove and form an electrical connection with the coating. Another lead wire is provided for the other coating, and that lead wire may be disposed in another similar groove.

Abstract: An electroceramic heater including a pair of metallized electrodes disposed upon the sides of an electroceramic body and a pair of lead wires ultrasonically welded and metallurgically to the electrodes, with the inner ends of the wires being swaged such that they have a generally flat appearance.

Abstract: An electroceramic heater including a pair of metallized electrodes disposed upon the sides of an electroceramic body and a pair of lead wires gap is welded to said heater. A specially sized copper pad is disposed between the lead wires and the electrodes.

Abstract: An insecticide dispenser capable of setting off a charge of insecticide to fumigate a room and then automatically shutting itself off before the completion of the dispensing of the charge of the insecticide, whereby the dispenser can be safely left unattended during the fumigation of a room. The dispenser includes a container for the insecticide and a fusible member that will break during the volatilization of the insecticide thereby to break the electrical circuit and turn off the power supply.

Abstract: A PTC heater has passages therethrough through which a fluid can flow to be heated. The passages are separated from each other by thin walls of PTC material. Electrical current flow is in a direction normal to the thin walls. A short duration pulse of high electric current is applied to the heater in order to eliminate any electrical shorts between passages.