Today I received normally closed solenoid valve which I am going to use in automated pot watering system , I realised the valve takes 24 dc volt as input and Arduino has maximum of 5volt , using some power booster I can convert it to some extent but I think 24 volt is too much .

So how should power 24volt solenoid valve from Arduino uno?enter image description here

  • Howmany power does the solenoid use? Get a 24V power supply, or your 19V laptop power supply may actually do the trick just fine.
    – Paul
    Nov 15, 2016 at 16:59

3 Answers 3


enter image description hereSince the solenoid requires higher current than the arduino can provide you can use an alternative power source for the solenoid (maybe a couple of batteries) and switch it with a TIP120 transistor.

  • Got it here : instructables.com/id/… Nov 15, 2016 at 13:13
  • Yes that was my source when i first implemented it. Nov 15, 2016 at 13:18
  • Actually I have plan to power over Ethernet if Arduino can handle 24 volt dc I can break part of voltage from same dc input to solenoid valve Nov 15, 2016 at 13:48
  • Arduino Uno Input Voltage Limit Nov 15, 2016 at 14:05
  • 1
    You can get a DC-DC (buck) converter, to step down the 24V to 5V.
    – Gerben
    Nov 15, 2016 at 16:08

You have 2 choices:

1 - Preferably, use a N-channel MOSFET. Best for usage of voltage between 9 and 60, these are great little modules that can control voltage flow.

2 - Use a relay. A little more expensive, but can handle main's voltage.

  • Why PNP instead of NPN? How do you turn off a PNP with only 5V?
    – Gerben
    Nov 15, 2016 at 16:06
  • @Gerben, my bad...
    – Dat Ha
    Nov 15, 2016 at 16:07
  • An “NPN MOSFET”? You mean an N-channel MOSFET, or an NPN BJT. Nov 15, 2016 at 16:37
  • @EdgarBonet An N-channel MOSFET. Could an NPN MOSFET also mean NPN BJT? Because I think I was clear enough by putting MOSFET in capitals.
    – Dat Ha
    Nov 15, 2016 at 18:47
  • 1
    A BJT can be either NPN or PNP. A MOSFET can be either N-channel or P-channel. There is no such thing as an NPN MOSFET. Nov 15, 2016 at 20:37

24V AC or DC? Relay would be good for either.

Low Rds N-channel logic level MOSFET (IRFL540) would be good for sinking DC current.

  • 1
    The OP said "the valve takes 24 dc volt as input" in his question. I think that means 24VDC. Dat Ha recommended using a N-channel MOSFET back on Nov 15, 2016. Do you think your answer adds any new information that may help the OP or any future visitors to this question?
    – VE7JRO
    Mar 14, 2018 at 0:46
  • Dang, I need to remember to look at the dates of the original question! That's the 2rd or 3rd time I've been caught up like that.
    – CrossRoads
    Mar 14, 2018 at 1:47
  • 1
    Do you think your answer adds any new information that may help the OP or any future visitors to this question?
    – VE7JRO
    Mar 14, 2018 at 2:06
  • No, feel free to remove the whole thing.
    – CrossRoads
    Mar 15, 2018 at 13:12

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