As illustrated, the switch circuit by capacitive oscillator, the integration network, and a comparator circuit relay control circuit. When the body close to the induction metal
plate, inductive capacitance to ground increases, the composition of the 555 astable multivibrator start-up or change in the oscillation frequency, alternating square wave output of the network after the three points, added to IC2 (LM324) with the phase of the comparator, and the set reference voltage, and outputs a negative pulse jump change, VT1 conduction, K pull, load circuit switched on. Conversely, disconnected. Induction plate size selection, should not be lower than the oscillation frequency of several thousand kHz.