| 摘要 |
<p>An electrically-powered heating panel in the form of an electric blanket comprises a dual coil heating element 2, a device 3a for supplying electrical current to the element 2 in pulse form, and a control (4) operable so as to at least reduce current flow to the blanket in the event of undue increases in "on" pulse duration, so as to prevent overheating of the panel. The device may comprise a thermal relay which supplies electrical energy to the blanket cylically, in "on" and "off" pulses of discrete form. The control may comprise a positive temperature coefficient thermistor operable whereby when the current "on" pulses become too long, (and therefore cause the blanket 1 to overheat), the thermistor rapidly increases in temperature and operates to reduce current flow. <IMAGE></p> |
