Electronic Systems Design’s Model 910210 UV Lamp Fail-Safe Switch is used with water purification systems and water vending machines. It measures the line current into the UV lamp power supply. When the line current is good, the switch is activated. When the line current is bad, the switch is not activated. The circuit requires no additional power to operate, as it steals its power from the lamp’s primary line current. It works with UV lamps with a nominal operating line current of 0.51 Amp at 115VAC.

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