5V Water pump and Arduino

I have a 5V water pump (2.3W) that I want to connect to my Arduino. Can I connect the pump with the 5v output pin on the arduino without any transistors or relays? If no, wich transistors or relays should I use?

The 5V pin cannot be used for motors and servos -- you need a separate motor power supply. Don't forget to connect all the grounds.

The attached image shows how to wire up a logic level MOSFET as the driver.

2.3W is almost 500 mA - plus a good bit for stall current.

Get a logic level MOSFET rated for 2-3A or better.

Here's one that should work for you. You can get them to handle more current if you need.

https://www.ebay.com/itm/5pcs-IRLB8721PBF-IRLB8721-8721-MOSFET-N-CH-30V-62AC-C-220-newC-C/273540328489?hash=item3fb0462c29:rk:1:pf:0

EDIT: Replaced link with proper MOSFET, thanks for pointing it out Wawa.

Bad example.
An IRF520 is NOT a logic level mosfet, shouldn't be used with 5volt logic, and certainly not with 3.3volt logic.
There are much better logic level mosfets out there.

That said, it most likely will work ok with that light load (~500mA).
Leo..

Wawa:
Bad example.
An IRF520 is NOT a logic level mosfet, shouldn't be used with 5volt logic, and certainly not with 3.3volt logic.
There are much better logic level mosfets out there.

That said, it most likely will work ok with that light load (~500mA).
Leo..

Oh my, is there a hole I can climb into. :-[ I just did a quick search on ebay and that's the main one that comes up and says good for 3.3v or 5v but I didn't verify in datasheet. Can't believe those are being sold to work with a PI. I do see the RDSon is 10v and high threshold so yeah would probably still work but barely.

Here's one that is logic level, IRLB8721PBF, sorry couldn't find a module but I'm sure they're out there. This one has 4.5v RDSon and much lower threshold, I verified this time. :slight_smile:

https://www.ebay.com/itm/5pcs-IRLB8721PBF-IRLB8721-8721-MOSFET-N-CH-30V-62AC-C-220-newC-C/273540328489?hash=item3fb0462c29:rk:1:pf:0

For the MOSFET I follow a few basic rules.

For the types mentioned above: IRL usually means logic level, IRF usually not. But the problem is that “logic level” may still require 4.5V. The IRL540 for example does not work with 3.3V logic level signals.

The second is: pretty much regardless of the VGS, TH value I look at the gate voltages the data sheet gives an RDS, ON value. If you need one for a 5V controller, you want to see RDS, ON values for VGS = 4.5V. If you need one for a 3.3V controller, you’re looking for something ~3V. If those values are not listed explicitly in the data sheet, it’s very likely not suitable for use at that voltage.

robsworld78:
Can't believe those are being sold to work with a PI. I do see the RDSon is 10v and high threshold so yeah would probably still work but barely.

That's eBay for you - people trying to dump such items with misleading descriptions isn't uncommon,
caveat emptor...

Don't read seller's descriptions other than to find the part number.

Then pick up the data sheet and check the actual numbers.

Often enough I do it the other way around: first decide on the part number, then find someone that's selling it.