摘要 |
<p>The invention relates to circuit protection devices which comprise conductive polymer PTC elements. The devices of the invention will provide repeated protection against sudden increases in current to high levels, e.g. 5 amps or more, in circuits which operate at, or are subject to fault conditions arising from, voltages greater than 100 volts, e.g. mains supply voltages. A particularly valuable use of the devices is in the protection of circuitry in telecommunication apparatus which normally operates at battery voltages, e.g. up to 75 volts, but which can be accidentally subject to voltages above 120 volts. </p> |