| 摘要 |
The present invention relates to a self-regulating electrical resistance heating element, to an appliance containing same, and to processes for their manufacture. The self regulating electrical resistance heating element comprises: a non-electrically conductive substrate (12); a first metal oxide (14) having a positive or negative temperature coefficient of resistance below a predetermined operating temperature deposited on said substrate; a second metal oxide (16) having a temperature coefficient of resistance opposite to that of said first metal oxide deposited on said substrate adjacent said first metal oxide; and first and second electrical contacts (18; 20) disposed such that a current can pass between the contacts through the first and second metal oxides. By placing the respective metal oxides, in e.g. discreet lines, tracks or areas, adjacent one another, with a contact there between or with a sufficient overlap to ensure a good electrical contact it is possible to provide self-regulating electrical resistance heating elements for applications where a large area (compared to 20 e.g. a kettle element) is needed, such as might be the case in a washing machine, dishwasher or tumble dryer.
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