Lie detector circuit design using transistors

This Lie detector circuit is designed using few common electronic components .The function of this lie detector circuit is based on the variation of the skin resistance that is used to vary the frequency of a tone oscillator . The contact rings can be two bars rings , about ¾ “ .This lie detector circuit can be powered using a 9 volts DC power supply or a battery . This detector circuit is not a very high efficiency project like other detector circuits which electronically measures changes in respiratory rate and volume, heart rate and blood pressure plus sweat gland activity that indicate arousal of the autonomic (involuntary) nervous system , but is very simple and can be used for educational study .