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Electronic lie detector

Electronic lie detector

A lie detector test-more correctly called a polygraph test-is really a whole battery of tests. It measures physical changes in our bodies when we undergo psychological stress. Measurements include pulse how fast your heart beats blood pressure, respiration how fast you breath and how much your hands perspire.The more you sweat, the better your skin conducts electricity. That is what this project does: it measures how good you, or anything, conducts electricity
What you need

3904 and 3904 transistors
4.7K and 82K ohm 1/4 watt resistors
.01 mfd ceramic disk capacitor
2″ 8 ohm speaker
9 volt battery snaps
18 guage solid (not stranded) wire
electrical solder, rosin core and a soldering iron
100% clear silicone caulk
Clear, flexible plastic sheet.

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