Arduino UNO power supply

Development Boards Arduino
1

Hi, i need to know how the power 230v AC to be converted to 12v DC to power up the Arduino kit. Since it is quite a big project we cannot have a separate battery power given for each kit. Can we use a step-down transformer? which brand is good.other than that what ideas can be imposed.grateful if u all can help me.

thank you

2

The Arduino boards have voltage regulators that transform the input voltage to either 5VDC or 3.3VDC. The bigger the difference between the 5V and the supply (12V DC in your case) the more the regulator has to work and the more heat is generated and energy wasted. Supplying around 7.5V is enough to let the regulator to its job. But perhaps you can make or purchase a regulated 5V supply with a lot of power and then supply that straight to the power rail of the Arduino without going through the jack and regulator. This would be more efficient if powering many devices.

There are lots of transformers out there on the market that you can buy which convert 230VAC to a smaller DC voltage, and as commodities they are going to be cheaper than if you build a transformer yourself (for which there are many schematics available on the WWW as well).

First you would need to calculate how many mA or A you need in total and then work from there.

3

You should be able to source some AC to DC power packs that have a 7.5 to 12 volt output locally or online. You just need a power pack that:

  • - Has the correct AC plug for your outlets
  • - Has a output plug that is a barrel jack and sized 5.5x2.1mm.
  • - Has enough output current for your application. The Arduino won't use much on it's own, 500mA to 1000mA would be sufficient.
  • - The output plug needs wired with 'tip positive' polarity. (most power packs are, but double check!)

    • http://www.voxxintl.com/images/common/A … _FAQ_1.png

    SV-Zanshin raises a good point on the voltage, more is not better and more will just waste power as heat. 12 volts is fine but a 9 volt adapter would be better. 7.5 volts isn’t a very standard amount, but that would be ideal if you could find one.

    4

    You didn’t mention what country you’re in, but I have a few comments that may be of some use:

    First, most “wall-wart” power supplies these days are “switching” power supplies. Without going into the details, they should have labels on them saying what the input is. Most “switching” supplies have a very wide input, e.g., “100 to 240 V, 50 to 60 Hz”. You might need an adapter to plug it into your local outlets, but those adapters should be fairly easy to find.

    Second, you might look around at what we call “thrift stores” (that sell used goods) for some chargers for the older cell phones (before they all switched to using USB chargers, which are 5V DC) for some that have a DC output in the range of 7V to 12V. If the connector is wrong, you might have to cut off the existing one, and use a [solder-on connector, or if you don’t want to solder, you could use a [screw connector. Either way, make SURE you get the polarity correct! (See TS-Chris’s reply above!)

    A third option is to use a 9V battery with this [adapter. I’ve used a similar adapter to power an Arduino for several hours from an alkaline battery (as a “pass-around” when I give presentations to various groups). Adafruit sells a [holder for four AA cells. (Note that you can also order this through Digi-Key.)](4 x AA Battery Holder with 2.1mm Plug : ID 3784 : Adafruit Industries, Unique & fun DIY electronics and kits)](https://www.sparkfun.com/products/9518)](DC Barrel Jack Adapter - Male - PRT-10287 - SparkFun Electronics)](DC Barrel Jack Plug - Male - PRT-11476 - SparkFun Electronics)