kindly give me the details of lie detector using microcontroller

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please give me the details of lie detector using microcontroller

This is a false capture circuit or a Lie detector. The basic principle of human skin resistance. While dry skin is a resistance of about 1 Mega ohm but if the moisture resistance of the skin is reduced. When the body is excited or scared or not sure that the skin is wet than usual.

The operation of the circuit is a circuit of R1 and R2 divide the line voltage and the probe used to measure the resistance of the skin, which is parallel to R2.So voltage drop across R2 is based on the resistance of the skin With is whether the skin resistance of about 1 mega ohm to a strong fall through about 4.5 volts, but if the skin wet (liar), the resistance is less than 1 mega ohm at a voltage drop across Of less than 4.5 volts. It uses the pressure is in the bias voltage to flow in Q1 - BC548, where Q1 and R3 buffer circuit to circuit.