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Lie Detctor


Codyhtml
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ok i got info on my transistor and soldered it in i hooked up the pot and it workes ether way it just reverses like you have to turn it left with it hooked up one way and turn it right hooked up the otherway but i checked ind i  can't find any shorts i thinght that would be the problem it dosent work i can't get it to drop below .6 millamps and then if i put the electrodes on and have sombody lie or somthing it dosent change even if i touch the electrodes toghter without a person so i don't know i bad cap wouldent be the problem a reversed or bad cap and it wouldent be a problem eith the transistor would it or is there probably a short and i just can't find it sorry for asking so many questions most of you guys could build this in like 1 day with parts from your junk box but i guess i'd never learn and be able to help other people later if i never got help

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Hi Cody,
The transistor isn't working or the batteries aren't 4.5V. The schematic shows a longer line for the positive terminal of each battery cell. Each of the two batteries are 3 cells and they could be AA cells.
With nothing connected to the electrodes the meter should try to go backwards between 0.7mA and 3mA depending on the setting of the pot.
With the electrodes shorted together, the meter should read between about 2.5mA (full scale for a 1mA meter) to backwards 3mA, adjusted with the pot and should be able to be zeroed. It should do the same if the capacitor is shorted.

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