The liquid detector is a detector with liquid alternating voltage and can be built using some common electronic components. Voltage alternative for this circuit is made using a gate with Schmit trigger function, which works as an alternative power oscillator. If between both electrodes is electrically conductive fluid as a result of recovery actio
n diodes D1 and D2, capacitor C4 is charged. When the capacitor voltage reaches the switching of logic gate N2 and connects relay device connected to it. When the electrodes make no longer contact, the relay switches off the device connected to it.