Transistor Amplification – Arduino Workshop Project Video #2

This is the 2nd video in the Arduino Workshop tutorials series in which I show how to properly use a transistor to amplify a digital output pin. This is a must when you have to drive high current devices from an arduino like high power led’s and motors. Any questions or comments are welcome please post them!



470 ohm 1/4W 5% Carbon Film Resistor pk/5

Catalog #: 271-1317

10K Ohm 1/4-Watt Carbon Film Resistor (5-Pack)

Catalog #: 271-1335
1N4001 Micro 1A Diodes
Catalog #: 276-1101


RadioShack® NPN Transistors (15-Pack)

Catalog #: 276-1617


5mm High-Brightness White LED (2-Pack)

Catalog #: 276-017





Duration : 0:8:26


25 responses to “Transistor Amplification – Arduino Workshop Project Video #2”

  1. Halo2maniaccc Avatar

    You don’t use PWM …
    You don’t use PWM like you would for a servo. You have to use digitalWrite in arduino on the pwm pin. That will create the speed control you want. Also you could hook it up to an analog pin and try analogwrite. I don’t have the code for it but if you google for examples of analogwrite/digitalwrite you will find a few examples.

  2. AKSoapy29 Avatar

    How did you do the …
    How did you do the PWM of a motor? Can you PM me the code? Cause I can’t get it to work.

  3. Halo2maniaccc Avatar

    You can use any …
    You can use any standard npn transistor the 2n2222 just happens to be easily available at radioshack.

  4. AKSoapy29 Avatar

    And do I have to …
    And do I have to use the 2N2222 or can I use a different one?

  5. Halo2maniaccc Avatar

    Yes you can hook up …
    Yes you can hook up an external power source to it as long as the arduino is connected to ground. It doesn’t have a set power rating it depends on what transistor you use some can handle small loads while others can handle massive loads. This transistor can work up to 36v. Look up the datasheets for these transistors they will tell you all you need to know.

  6. sinnerrom Avatar

    instead of …

    instead of the Arduino power source can be used to connect to another power source? and which is the maximum and minimum volts and amps of that?

  7. tiputipu0052 Avatar

    hi, can you tell me …
    hi, can you tell me for building a AM transistor radion, if i want to use 2 transistors as darlington…then use amplifier for further amplification… ,,what should be the value of bias resistor(collector. base)in darlington…..i usually use bias resistor 100k for single transistor …similarly if i use 3 transistors as darlington..what should be the bias resistor..similarly if i use 4..5..6…

  8. Halo2maniaccc Avatar

    The motor was …
    The motor was pulled from a 6v rc car so I would assume its rated for between 5v and 7.5v to be safe. The max load of the circuit isn’t based on voltage, instead its watts (voltage x current). There is a max voltage of about 30v for that transistor but it can only push about 600mw so the current would be low. So the circuit doesn’t have to run at the running voltage of the arduino which allows a world of possibilities.

  9. samtheman1993388 Avatar

    So by using this …
    So by using this circuit what is the max load that you can power? I am guessing 5v as that is what the Arduino board runs at?? Also can you remember the voltage of that motor?

  10. Halo2maniaccc Avatar

    An LED is still a …
    An LED is still a diode so I would assume that it SHOULD work. I would ask someplace like 4hv because I don’t really know every difference between the two. My personal suggestion would be to just get the proper diodes from radioshack or online.

  11. dodgedart74 Avatar

    very stupid …
    very stupid question but, ive just been using LEDs for my diodes, that has no long term effects does it?

  12. herctrap Avatar


    we can …

    we can use it

    but how we can?

  13. herctrap Avatar

    can we use a mosfet?
    can we use a mosfet?

  14. Halo2maniaccc Avatar

    The transistor I …
    The transistor I used in the video has the same pin out as the one from Radioshack. Look at the flat and convex side of the transistor in the video.

    I don’t know why Radioshack doesn’t have them online but the diagram will be on the back of the package that they come in. It has tech specs about it as well as the basic pin out.

    Make sure you use the 2n2222 transistor because that “pack” of 15 only has 5 of them, the other 10 are different types. They will work but have different power ratings.

  15. edicus25 Avatar

    Great video, but …
    Great video, but what are the pins for the transistor? I looked for the data sheet on the Radio Shack web site and couldn’t find it.

  16. Halo2maniaccc Avatar

    O yea thanks to …
    O yea thanks to addzkebabs I just remembered that you can get them at Radioshack if you really need to go local or sometimes at hobby shops.

    However I would recommend that you DON’T go to Radioshack. It may be convenient but they will charge you like $20 for a breadboard that is slightly larger then the one in the video. If you go to ebay you can get one that is like 6 times larger, w/ free jumper wires and shipping for around $18!

  17. Halo2maniaccc Avatar

    The white board …
    The white board with all the holes in it is called a breadboard. It is used for rapid prototyping of circuits. You simply put component’s on the board and use wires and things to jump power around. This is a MUST HAVE and yes it will work for those LED’s. The blue circuit was the programmable part the white board was only for connecting it all together!

    You can get them at Sparkfun or ebay just search for “breadboard”. The ones on ebay are just huge w/ free shipping for a really low price!

  18. addzkebabs Avatar

    your a goose, but …
    your a goose, but anyway your get a braed board(white thingy) from any electronics store!

  19. hasnachos Avatar

    wow i ad no idea …
    wow i ad no idea what a transistor was or did, but now i see what its for… and the white circuit thing where you plug everything into, where can you buy one? would one of those work for programming a set of leds that can strobe in various blinking patterns?

  20. Halo2maniaccc Avatar


  21. st1gma888 Avatar

    Good stuff man.
    Good stuff man.

  22. Halo2maniaccc Avatar

    No problem!
    No problem!

  23. UserIsAnFBIAgent Avatar

    Thats pretty cool …
    Thats pretty cool stuff man, thanx allot.

  24. Halo2maniaccc Avatar

    Well if you get …
    Well if you get four of these and place them in an H bridge configuration you can have bi directional speed control but only for brushed motors. For brushless I believe controlling them in more complicated so I would have to check in with that. As for servos they already have the circuitry inside, all you have to do is connect them to a power supply and send them a pwm signal.

    Thanks for watching!

  25. addzkebabs Avatar

    Awesome! um, is …
    Awesome! um, is this going to power servo’s and brushless motors (with or with out the esc attached)? thanks.

Leave a Reply