Lie detector electronic project circuit design using transistors
This lie detector electronic project is designed using few common electronic parts. This lie detector can test a person whose status is modified in certain situations (as in the polygraph test) by "observing" biofeedback. Because a person's skin resistance depends on the state in which that person is, skin resistance increases with depth state of relaxation.
The electronic scheme presented, affects skin resistance frequency of oscillator built with transistor T2 . Both electrodes, with ring shape, are applied on two fingers of a hand. The more deep state of relaxation corresponds to a lower frequency sound that you will hear in your headset.
The second oscillator, built with transistor T1 also produce sound. In this case you can still adjust the height of the potentiometer P1 sound at frequencies corresponding to the other oscillator, the deepest state of relaxation. If the two oscillator signals are run separately to a stereo headset, the maximum relaxation is achieved when sound from the right side sounds has the same frequency like sound from the left side.