an electric circuit device operable under a power supply includes : a circuit ; a first switch connected between the power supply and the circuit ; a capacitor tending to produce a first leakage current ; a second switch connected between the power supply and the capacitor , the second switch producing a second leakage current when it is cut off , the second leakage current being less than the first leakage current ; and a switch controller for turning on the second switch while both the first switch and the second switch are turned off , and after a first time passes for turning on the first switch .