Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can I use a ordinary 1K ohm potentiometer to convert 12V to 5V?

  1. May 5, 2014 #1
    I have a 1K ohm potentiometer.(datasheet is attached below). My aim is to convert 12V to 5V,which I would then apply to power the Arduino microcontroller. I'm not quite sure if I CAN use the potentiometer I have ie T93 YA 1K 1035 to do this conversion.
    The datasheet says that the maximum voltage applicable for 1K ohm is 22.5V. But,the MAX.power given is 0.5W. This doesn't make concurrence since my input voltage is at 12V and 0.6 A,which means the power applied would be 7.6W.So,does that imply this potentiometer could not be used for the purpose of 12V to 5V conversion?

    How do I go about calculation?
    I'm new to electronics stuff.

    Attached Files:

  2. jcsd
  3. May 5, 2014 #2


    User Avatar
    Science Advisor

    Since the Arduino consumes a varying current but requires a fixed voltage you should use a voltage regulator. The 5 volt regulator part number you should look for is 7805, they are a commodity available everywhere. That will solve your problem better than any potentiometer you might use. If you use a potentiometer, at some time you will certainly exceed the specified maximum input voltage to the Arduino which will almost certainly destroy it.
  4. May 5, 2014 #3

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    Baluncore is exactly right, you need something automatic.

    12 volts - is this for use in an automobile?

    If so you might consider LM2931 regulator. It comes in 3 terminal like 7805 but is intended for automotive application so includes two nice features:
    1. It's reverse polarity protected to protect your arduino against reversed battery leads when somebody makes a mistake giving you a jump-start
    2. It has overvoltage protection to around 60 volts which protects against alternator surge caused by loose battery cables.

  5. May 5, 2014 #4


    User Avatar
    Gold Member

    Using a pot, or a resistor to drop voltage for a uP will never never never work reliably. Don't even think about it.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook