
We’ve had a few emails and posts about folks who wanted to build their own lie detector, here’s one (and how it works) – “The circuit diagram of the Lie Detector is shown above. It consists of three transistors (TR1 to TR3), a capacitor (C1), two lights or LEDs (L1 & L2), five resistors (R1 to R5), and a variable resistor (VR1). Suitable transistors to use are BC547, BC548 or BC549, or any other small NPN transistor. The Lie Detector circuit works based on the fact that a person’s skin resistance changes when they sweat (sweating because they’re lying). Dry skin has a resistance of about 1 million ohms, whereas the resistance of moist skin is reduced by a factor of ten or more.” Link.
4 thoughts on “Lie Detector Electronic Kit and Circuit Explanation”
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Where do we get the parts to build it.
What parts do we need.
How much do they cost and make sure there for kids.
sir please tell me whole process to make a lie detector , that where resistances implement and where led and electrode implement.tell me whole process to make a lie detector step by step