I need to power an actuator that requires 12 volts and consumes between 5 and 10 amperes depending on the weight it is charging. Therefore I bought a power supply of 12 volts and 10 amperes.

My intention is to send in the arduino output the 12 volts and the current provided by the power supply.

The options that I have thought are the following:

a) Connect the power supply to the arduino input pins and send the voltage and current from the power supply to the actuator through the arduino output (I know I could do it directly to the actuator, but I am interested in doing it through of arduino since it will involve programming code to put conditionals)

My doubt with this option is if I do not damage the arduino by connecting that power source with that amperage. If there is no problem, my question is if I could handle the current of the power supply at the output or the current could only be handled by what arduino gives that would not be much.

b) The other option that I think is simply to send a flag to the output and then this flag activates the power supply in some way and then I could use the 12 volts and the 10 amperes to connect them to the actuator.

I would like you to guide me on the alternatives I have thought about and tell me what would be the right thing to do, or if you know some other way in which you should do it.

Thank you very much in advance Cheers

  • 1
    sounds like the arduino will make a great fuse .... you cannot send 10A of current through the arduino ... research how to control motors with the arduino
    – jsotola
    Commented Jun 29, 2019 at 6:02
  • 1
    Think "Relay". Google that plus the magic "Arduino" keyword and you'll see lots of results that give you some nice circuits.
    – Majenko
    Commented Jun 29, 2019 at 10:44
  • @Majenko I was just checking that on the internet, my question now is whether it would be better to do it with transistors because the relay is mechanical and could be damaged and have a short lifespan, besides if I could do it with transistors considering these voltages and currents? Thanks :)
    – punk code
    Commented Jun 29, 2019 at 16:35

2 Answers 2


As others have said, an Arduino pin can't handle 12V, and can't handle anywhere near 10A of current directly. A digital pin on an Arduino is limited to 20mA, or 1/500 as much current as you need, at 5V, which is less than half the voltage you need.

If you try to connect 12V to a pin on an Arduino pin you will almost certainly destroy that pin, and may destroy the entire Arduino. If you try to source or sink even 1/100 of the current you are talking about through an Arduino pin, even at 5V, you will also probably destroy that pin and possibly the entire Arduino.

This sounds like a good application for a power MOSFET transistor. With that much current you'll need to put a heatsink on the transistor.

Here's one that would work:


You'd use a logic pin from the Arduino to control the gate on the transistor, and the transistor would switch 12V at high current with very little resistance.

If the actuator is inductive, you'll need to protect the transistor with a suitably large "flyback diode" to protect it from the reverse current (or "back EMF") you get from an inductor when you remove power from it:


  • It seems a good solution.Now Im going to research how to control the current and voltage levels with the mosfet. Thanks :)
    – punk code
    Commented Jul 1, 2019 at 7:29
  • I see I need to connect the 12V power supply to the mosfet and the lineal actuator, If I am correct?. And then i Would need another independent source of 5V for the arduino, or I can use the same power supply of 12 V by reducing with a voltage reducer, if this is the case what happen with the current of the source that is 10A, There is no problem since arduino will only consume the current it needs?
    – punk code
    Commented Jul 1, 2019 at 8:26
  • PD I am using a lineal actuator.
    – punk code
    Commented Jul 1, 2019 at 8:41
  • The Arduino has a built-in voltage regulator. You could feed 12V into the barrel connector on the Arduino and it would regulate that down to the 5V it needs. As long as your power supply is strong enough to drive your actuator and the Arduino without too much voltage droop it should work, although as the actuator turns on and off there will likely be significant variation in the voltage supplied to the Arduino. You should probably add filter capacitors to the feeds to both the actuator and the Arduino to even out the voltage.
    – Duncan C
    Commented Jul 1, 2019 at 12:17

Duncan's answer is how I would do it as well. Indeed that is how I did do it as well.

Having said that the challenge I had to work out was how to mix the voltages. For me, this was the hardest part of the project as I had little idea about current and voltage.

I also wanted to use just one power supply.

So what's the problem? The LED strip requires 12V@1Amp. Which is, I think the upper limit for what can be supplied to arduinio's power jack. Also the arduino can only supply a small current at 5v to switch the relatively massive 12V 1A led circuit.

The MOSFET was the answer (after multiple failed attempts). MOSFETs are apparantly safe for connection to Arduino as there is apparantly no electrical connection between the base (where the arduino connnects) to the other two pins (where the power flows). The articles I read say that the base is insulated from the rest of the circuit by a piece of glass!

Anyway, Here is my Motion activated stair lighting project. I am not an electronics expert, but FWIW, this has been running flawlessly 24x7 for almost 12 months now.

  • Hey thanks a lot for your answer, and also for sharing your project :), Cheers.
    – punk code
    Commented Jul 1, 2019 at 7:29

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