The thermal photocontrol street lights use thermal relays instead of electromagnetic relays. So there will be a heater heating up devices like the bimetals and then actuating the mechanical contact. One of the advantages of thermal photocontrol is that the relay has less power than the electromagnetic relay. Another merit is that its slow response will not violate the photo control, causing shades or flashes.
Больше чтения: Рекомендации по проектированию светодиодного уличного освещения в умных городах
