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Bed wetting alarm

Posted: Sun Jun 12, 2016 12:50 am
by G8RPI
Nice circuit aprart from the mains power supply. A unit like this that is by design in contact with a wet person should ideally not be powered from the mains, and if it is the power supply MUST be a low leakage medical grade type. The maximum leakage current for this type of application is 300uA. see
A power supply can have high leakage even without a fault. First (and possibly last) thing you know is when the alarm goes off and you reach for the (grounded) bedside lamp........
Best method is stick with battery power.