Symmetrical breaking current is the moment when fault occurs maximum fault current is observed and decays with respect to time. Symmetrical breaking current = RMS value of ac component of short circuit current at the instant of separation of the contacts. Symmetrical breaking capacity is less than asymmetrical breaking capacity.
When voltage changes occur in rapid succession, with magnitudes large enough to cause lighting level variations. The human eye-brain response is most sensitive to periodic r.m.s. voltage changes that occur at around 8 - 10 cycles per second.
The function of a thermopile is to transfer the heat radiation emitted from the object to a voltage output. The output is in the range of tens or hundreds of millivolts. Thermopiles are used to provide an output in response to temperature as part of a temperature measuring device
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