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Emergency LIghting


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11 hours ago, Jaco de Jongh said:

Dave, how does the globe know the power is off, how do they differentiate between you switching off the power and a power failure?

Technically it is possible. If the switch is off, then the power is off AND the terminals of the lamp is open circuit. But if the switch is on, then either there is power on the terminals OR the terminals will be almost short-circuited (the grid that it is connected to appears almost as a dead short). So with a bit of clever circuitry the lamp can determine whether the switch is on, even if the power is off.

Whether this is what they actually do is another question of course.

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