Wall Adapter Power Supply - 9VDC 650mA

High quality switching 'wall wart' AC to DC 9V 650mA wall power supply manufactured specifically for Spark Fun Electronics. These are switch mode power supplies which mean the output is regulated to 9V (no more 14V outputs!) and the capable output current is much higher (650mA!).

These will power most projects that don't require more than 650mA of current. Center-positive 5.5x2.1mm barrel connector.

Works with 100-240VAC inputs.

Check out our Unregulated Power Supply Tutorial

Wall Adapter Power Supply - 9VDC 650mA Product Help and Resources

How to Power a Project

February 7, 2013

A tutorial to help figure out the power requirements of your project.

Light Up Your 3D Printer's Bed

June 27, 2018

Having issues viewing your print in a dark lit room? In this tutorial, we will be using LED strips to light up a print bed's area on a LulzBot 3D printer!


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • windrago / about 13 years ago / 2

    Does this work with Arduino 2009 or fries it?

  • JGG / about 13 years ago / 2

    Are the "guts" available just as a circuit board (populated), preferably with some mounting holes? If not, suggestions on where to buy something similar, or maybe make the schematic available? I'd like to use it as part of an embedded system.

  • Tim R / about 13 years ago / 2

    Be careful with what outlets you plug it into. The prongs can be pulled out if the outlet applies too much pressure. The retail version I purchased from Micro Center last weekend ended up this way.

    • cmlburnett / about 12 years ago / 1

      Ditto, and the metal pin was left in the socket. One of the few times I've intentionally had to test the insulation on my pliers.

    • Gizmo E. / about 13 years ago / 1

      Yep, mine did the same thing. Except mine actually cracked the whole faceplate in a couple places as well.
      Reattached the prong, and still had to throw away adapter... put out 9V and seemed to short whenever a load was applied lol.
      Still, the price is pretty hard to beat..

  • BricoGeek / about 14 years ago / 2

    European plug please!!!

  • tweedius / about 10 years ago / 1

    Just bought the "new" version of this and it died in a little over 3 months. When I say died I mean that it turned into a sine wave generator peaking at ~14V.

  • Member #522981 / about 10 years ago / 1

    If possible, ship with order 957252

  • Member #168373 / about 12 years ago / 1

    I bought it, and finally tested it. Found out the unit is cracked. The screw isn't holding it together, but it just lightly is snapped in. Won't buy this anymore. The one from Amazon was same price, no issues!

  • Member #196151 / about 13 years ago / 1

    These make the best guitar pedal adapters! They take up one plug slot (very convenient) and they put out very clean voltage. If you play electric guitar I would recommend to buy a handful of these. Before you use them, remember to reverse the wires because you need negative tip with pedals. It takes 5 minutes to remove the cover and switch the wires, then you are good to go.

  • Member #159066 / about 13 years ago / 1

    Is it possible to order this with a longer cord? The length works for what I need sometimes, but I could use a couple extra feet for some of the powered chairs I use these on.

    • Young Maker / about 13 years ago / 1

      Solder on some dual conductor stranded wire between the connector and the cord, observing polarity :).

  • timballas / about 13 years ago / 1

    Man, I love you guys at Sparkfun. I really love the Phillips head screw and easy access tabs! It's also great that you don't squirt these things full of silicone or glue or whatever crap most have in them.

  • After a 3.3V voltage regulator, can I safely run this at a higher current? Say at 1A?

    • Ivan747 / about 13 years ago / 2

      Depending on the regulator: if it is a linear regulator (and it probably is) then no, the maximum output would be about 650mA. What a linear regulator does if to act as a series resistor, dropping 9-3.3V which equals 5.7V as heat. You might have used a resistor to drop the voltage going into an LED, tis works almost the same.
      The difference between a regulator and a resistor, in this aspect, is that a regulator knows the current flowing and adjusts itself to compensate the difference. So basically is behaves like a smart resistor that adjusts it's resistance based on the current flowing through it.

  • Scrubb / about 14 years ago / 1

    What is the configuration of the barrel connector? polarity/hot/etc? Is there a manual or schematic blow up?

    • Member #302270 / about 12 years ago / 1

      It Says Center-positive 5.5x2.1mm barrel connector

    • rfordh / about 14 years ago / 1

      The product description says "Center-positive 5.5x2.1mm barrel connector."

  • SteveL / about 14 years ago / 1

    Could I use this to power an Arduino?

  • g123456 / about 15 years ago / 1

    This is not UL listed or CSA approved. Might be important if you need something that is.
    Does anyone know where I can find a safety-certified version of a 9V >500mA adapter?

    • Dickcheney / about 8 years ago / 1

      I usually make it a rule to only leave an adapter plugged in unattended (to charge a battery or power something that I want to keep on) if it is UL listed.

    • MatthewFarrow / about 13 years ago / 1

      15W 9V Adaptor
      Claims to be UL and cUL approved. Not sure about CSA.

  • Aerodyno / about 15 years ago / 1

    And by three 'pins' I meant "prongs" ... you know, the ones that go in the wall socket. Connect negative to ground, so your arduino gets a true ground instead of a floating one.

  • Aerodyno / about 15 years ago / 1

    If you could make one that has three pins, so the negative output is connected to ground, that would be awesome. Right now I'm having issues with some sensors because I don't have a true ground on my arduino... Of course I discovered these problems only when I disconnect USB (which has true ground, through my laptop power supply) and connect this power adapter.

    • Try a 10K pull-down resistor to ground, might help stabilize the sensors by blocking some of the floaty-ness. :)

    • rfordh / about 14 years ago / 1

      That seems strange that your project isn't working with a floating ground. What kind of sensors are you using?
      If you really need a true ground, just connect a ground pin on your Arduino to ground directly. You don't need the power supply to do it for you.

  • h3X / about 15 years ago / 1

    Does this plug work in Europe? The pins look different from what I'm used to.

    • BB / about 15 years ago / 1

      Yes it does (works at 220V), but you'll need a plug adaptor to fit your sockets.

Customer Reviews

4.6 out of 5

Based on 12 ratings:

Currently viewing all customer reviews.

2 of 2 found this helpful:

Fantastic little wall adapter

Shipped fast and works great!

2 of 2 found this helpful:

Gets the job done at a great price

I have a 9 and 12 volt version of these , both work excellent with decent cord length. Ive been playing with lm386 amps and these make excellent power sources

2 of 2 found this helpful:

Best power supply for arduino on the market

I just powered up 160 Arduinos with these power supplies with no issues!

1 of 1 found this helpful:

Its Excellent!

It helped me in my projects,

1 of 1 found this helpful:

Item TOL-00298, has my approval

I have been purchasing these for a couple of years now to use on some of my production run product. I know I have purchased at least a couple hundred. I have never had one come back from the field with a problem other than someone inflicting damage to the cord. Good product at a reasonable cost. Thanks!

Good piece of gear

Bought this to power up a small breadboard for my Arduino work.. Built the kit, plugged this and voila, lights and power. Thanks.

It does exactly what you expect

By providing power from the wall in the specified manner

Good power adapter

With all the wacky cheapo sub-par products out there. This adapter is consistant. Greenbacks well spent. Last thing i want to do is stick a outboard regulator to something thats supose to do its job inthe first place

Great item to have for small projects

Compact, suitable for all small projects that requires 9V and low current. Good quality product.

Gets the job done.

Works great and is relatively compact. Could be improved by offering a version with the orientation of the plug rotated 90° also the LED is very bright, a dimmer indicator would be sufficient, or possibly no LED at all.