| 摘要 |
A resistor particularly useful as a self-regulating fluid heater has passages extending through a body of ceramic resistance material of positive temperature coefficient of resistivity (PTC) and has ohmic contact coatings formed on the inner walls of the passages. The passage walls define thin webs of the resistance material between adjacent passages and are of uniform thickness end to end. Slits located in the walls at the ends of selected passages accommodate electrically conducting means which interconnect the contacts in selected pairs of the passages. In that way, predetermined groups of the contacts are interconnected at respective ends of the resistor so that when the groups of contacts are connected in a circuit, electrical current is directed through the thin webs of resistance material between contacts of opposite polarity in adjacent passages, thereby to heat the resistor to self-regulate its temperature to efficiently generate heat for transfer to a fluid directed through the passages. Electrically conductive coatings are applied to the ends of the resistor body to be received in the slits and the body ends are then abraded for removing coating material outside the slits, thereby to interconnect the desired groups of contacts. |
