Random Nerd Tutorials

Circuits – How to identify PNP and NPN Transistors (with a Simple Circuit)


In this project I’ll make one of the easiest PNP and NPN circuit identifier on earth. You’ll see how easy It is to make one! I’ve also made a post to help you learn more about the Transistors theory. (I highly recommend you to read it first).

This project is great to learn more about:

  • Transistors
  • Simple DIY Circuits
  • PNP and NPN TransistorsElectronics components, transistors

Parts Required:

  • 1x LED
  • 1x Pushbutton
  • 1x 1k Ohm Resistor
  • 1x 10k Ohm Resistor
  • 1x Breadboard
  • 1x 9V Battery (and Battery Clip)
  • Some Wires


Pnp circuit schematics

Final Product

PNP and NPN transistor identifier

PNP and NPN transistor identifier

Watch out it works:

Basically when you put a PNP transistor on the circuit the LED turns ON if you hit the pushbutton. If you put a NPN transistor on the Circuit the LED will stay OFF.

Thanks for reading, you can contact me by leaving a comment. If you like this post probably you might like my next projects, so please support me by subscribing my blog and like my Facebook Page. Ok? It’s free…  Make sure you also share my projects It helps me a lot!

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