主权项 |
1. A thermally sensitive electrical security device comprising:
a. a thermally sensitive switch, capable of both opening and closing repeatedly responsive to temperature within at least one thermal isolation chamber; b. at least one primary heater, the switch and primary heater being electrically coupled in series; c. a secondary, lower temperature heater that is continually connected to a power connection means; d. an output load receptacle, coupled in series with the switch and the at least one primary heater, for connection to a load providing a security output function; and wherein the switch, the at least one primary heater and the secondary heater are located within the at least one thermal isolation chamber; wherein the switch, the at least one primary heater, and the output load receptacle are electrically connected so that when the device is powered through the power connection means, the switch is being heated by the at least one primary heater and the secondary heater to reach a first given temperature, the switch opens, and then closes at a second lower given temperature after a time period determined by heat transfer between the at least one thermal isolation chamber and the environment, thereby preventing and allowing respectively powering of the output load receptacle to power the security output function by generating a variable time switching of the load.
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