EngineeringSlash- The electronic projects,electronic project,electronic schematic,electronic design » Lie detector http://www.engineeringslash.com Engineering blog- electronic circuits , electronic projects,electronic schematic,electronic design,simple circuit and hobby circuits Tue, 09 Feb 2010 05:03:16 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Lie detector circuit http://www.engineeringslash.com/simple-circuits/lie-detector-circuit.html http://www.engineeringslash.com/simple-circuits/lie-detector-circuit.html#comments Sat, 23 Jan 2010 10:46:06 +0000 admin http://www.engineeringslash.com/?p=165 lie detector

Here’s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring skin resistance, which goes down when you lie.

Here are the details of the specific parts you will need

Part Total Qty. Description Substitutions

R1 1 33K 1/4W Resistor
R2 1 5K Pot
R3 1 1.5K 1/4W Resistor
C1 1 1uF 16V Electrolytic Capacitor
Q1 1 2N3565 NPN Transistor
M1 1 0-1 mA Analog Meter
MISC 1 Case, Wire, Electrodes (See Nots)

Notes
1. The electrodes can be alligator clips (although they can be painful), electrode pads (like the type they use in the hospital), or just wires and tape.

2. To use the circuit, attach the electrodes to the back of the subjects hand, about 1 inch apart. Then, adjust the meter for a reading of 0. Ask the questions. You know the subject is lying when the meter changes.

http://www.aaroncake.net/circuits/lie.htm


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