Water Activated Relay
Circuit :  Marin Lukas, Croatia
Email  :  marin.lukas@zg.hinet.hr


Notes (English follows) :
Ovaj sklop je projektiran da ukljuci relej kada se na knotaktima pojavi voda.Tranzistor T1 moze biti zamijenjen s 2N2222A.Tranzistor T2 mora biti BC108. Na kolektor tranistora T1 osim releja mogu biti spojeni signal injektor, LE dioda, zarulja i ostali signalizacijski elementi.

In his circuit Marin has used two transistors wired as a high gain compound pair. Transistor T1 may be a 2N2222A and T2 a BC108. The current gain will be the product of each transistors beta, which will be a minimum of 140 x 110 or 15400. The power supply used can be any voltage from 4.5 to 15 volts, a typical 5 volt relay may require 60 mA to operate, in which case any fluid which passes a minimum current of 4 uA will activate the relay. This is easily achieved with tap or rain water.

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