# What DC power supply should I get?



## theinteresthunter (Jan 30, 2016)

I'm automatically controlling my point-to-point train with an Arduino that I've programmed. I need a 12v DC power supply to run the train.

Can anyone recommend a 12v power supply? The amps are my main concern, I think. 

My locomotive O gauge Williams diesel locomotive SD45-201. The details of that engine say it has a 6-amp reverse board. Thus, do I need to get a 12v power supply that can do 6A? 

I'm not knowledgeable on wattage and amps... and that's why I'm looking for your help. Thanks!


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## wvgca (Jan 21, 2013)

I you are looking for a 12V supply, I assume that you are powering the Arduino and shield both off that supply... 
The current rating of the supply is dependant on the current rating of the motor shield.. 
do you know what the shield is rated for??


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## theinteresthunter (Jan 30, 2016)

I think the shield's current rating is 2000mA.

Here are the specs for the motor shield (MotoMama v2.0):
https://www.itead.cc/wiki/MotoMama

I was planning on powering the Arduino and shield separately. Not because of any reason other than I thought that's what needed to be done. Case in point: I bought a 9v power supply for the Arduino and am now shopping/inquiring about a 12v power supply for the shield. If the right thing to do is to power them both from one supply, then I'll do that. I just thought they needed to have separate power sources. I can solder and such. My creativity is high, but my electrical theory is lacking.

(I checked out your train layout pics. Nice intensive work.)


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## wvgca (Jan 21, 2013)

in general, the Arduino and shield can use the same power source for 12V or less, for over 12V to the shield, the Arduino should be powered by the USB port 
In the case of the shield that you refer to, it looks like it needs 5V [which can be passed from Arduino], and 7-15V as well ..
In any case the L298 is around 2A maximum output... so a 12V supply of 2A would be okay ..for both the Arduino and shield supply


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## theinteresthunter (Jan 30, 2016)

Cool. Thanks for the help. I'll get a 12v 2a power supply.

On another note:
Do you think the 6-amp reverse board on the locomotive itself is limited by motomama sheild? If the locomotive's 6-amp reverse board is pulling 6amps, but the shield only can do 2amps... is there any sort of issue there? Newbie to the theory.


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## wvgca (Jan 21, 2013)

that question I leave to the forum O scale experts, I know nothing about those ...


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