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Topic: Power a 1A arduino standalone circuit without regulator (Read 131 times) previous topic - next topic

jeanot1314

Hi,

I made a circuit with around a 100 LED. It need almost 1A at 5V to work.

As the limited current of the Arduino is 500mA over the USB (because of the fuse), i decided to make an Arduino standalone. Everything is working fine, i just have problem on the power part :

I can use a 9V (or more) power supply with a regulator like a L7805. But the dissipation make the regulator getting very hot so i have to add a radiator. My circuit is working fine with this solution.

To simplify my circuit i had the idea to use a 5V/2A power supply (which are very cheap on ebay) and to plug it directly to the 5V circuit of my board (with 10uF cap as filter). But my circuit give me some very bad results turning on the LED... I can't really use a regulator to have more than 4.5V output with a 5V power supply (tension drop a lot) right?

In theory, a 5V/2A power supply should give me a nice and clean 5V (same than a regulator) no? So do i need to make a better filter?

Thanks for your help, i am quiet stock in here :s

Boardburner2

To simplify my circuit i had the idea to use a 5V/2A power supply (which are very cheap on ebay) and to plug
Post a link to the supply you are using

jeanot1314

yes,

it s this kind of supply :
http://www.ebay.com/itm/Useful-Power-Supply-Converter-Adapter-EU-Plug-AC-100-240V-to-DC-5V-2A-Switching-/121487306561?pt=LH_DefaultDomain_0&hash=item1c49352f41

weedpharma

First mistake is to believe component ratings on unknown ebay stores!!

Weedpharma

Boardburner2

#4
Feb 27, 2015, 01:13 pm Last Edit: Feb 27, 2015, 01:18 pm by Boardburner2
That psu does not appear to be regulated from the sticker.
They normally boast that.

It says switchmode in the text, but iv had similar before which turned out to be just rectified ac.

Have you measured its output voltage ?

jeanot1314


Yes i did,

I have 5.12V on output. I will try a little test to see if the supply can handle at least 1A

Thanks for your answers  :)

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