Breadboard Lie Detector

this fun easy project can be made using a breadboard and very little tools.


based on this project, but this project was made on a stripboard

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Step 1: Parts, Components and Tools!


1. Red and green 5mm LEDs (Red x1) (green x1)

2. 1 Breadboard, preferably a big one like the one i have x1

3. 10K Resistor x1

4. 47K Resistor x1

5. 470R Resistor x1

6. 1M Resistors x2

7. 3 pin potentiometer x1

8. Knob for potentiometer x1

9. 2N3904 transistors x3

10. 0.1uf mylar capacitor x1

11. 330uf 50v capacitor

12. 10M Bell wire/Stranded wire, Bell wire is Better x1

13. Aluminium foil

14. Tape

15. 9 volt battery clip

16. 9 volt battery


1. Wire cutters/scissors x1

2. Wire strippers x1 (Optional)

Step 2: The Schematic

So If you know how to read schematics, Well Done! you can easy make this without scrolling down even more. So bye i guess? But the people who don't know how to read circuit diagrams please email me at Thank you

Step 3: Bread Board Layout

the Image shows you the layout of a SMALL Bread board, Unlike the one i used to build the lie detector. I used a RH-32 Breadboard

Step 4: Simple Schematic!

this is a simpler version than the other schematic

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    7 Discussions


    Question 1 year ago on Step 4

    Where's the capacitor & potentiometer?

    Daniel Leviathan

    1 year ago

    How much volt with Mylar 0.1uF capacitor was ??


    2 years ago

    does the 0.1 uF capacitor have to be mylar? and where does the 50V 330uF capacitor go?


    1 reply

    Reply 2 years ago

    yes you do. And the 50v 330uF capacitor is placed, connected to the black wire of the battery clip and the potentiometer, (BTW the simple diagram is slightly wrong as the black and red wires should be switched around so the black wire is connected to the capacitor)


    3 years ago

    on the simple schematic the battery clip wires are the wrong way round black goes to the capacitor and the red goes to the led