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Author Topic: Arduino ac adapter  (Read 3929 times)

dhouston

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Re: Arduino ac adapter
« Reply #15 on: June 04, 2015, 07:55:50 AM »

This one probably is a linear model - you also need a $0.95 2.1mm adapter (on the right of the page).
http://www.parts-express.com/parts-express-12-vdc-1000ma-ac-adapter--120-050
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bkenobi

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Re: Arduino ac adapter
« Reply #16 on: June 04, 2015, 10:21:33 AM »

These guys are just down the road:

http://www.vetco.net/catalog/product_info.php?products_id=14098

I'm still looking around, but that seems like a valid candidate.

Brian H

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Re: Arduino ac adapter
« Reply #17 on: June 04, 2015, 11:20:52 AM »

Just remember. If the supply is not regulated. It output maybe high with a light load and low with a larger load. Than what the 12 volt 1 Amp rating is.
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bkenobi

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Re: Arduino ac adapter
« Reply #18 on: June 04, 2015, 11:34:33 AM »

I am confused on how the current is determined on power supplies like these.  I originally thought that the PSU would convert the 110VAC to the voltage and current specified and that would be forced through the electronics that are plugged in.  But at some point I was told that in reality, these PSU's can provide the current at the designed voltage.  So, if you have a device that needs 12VDC@0.5A, as long as the wall wart is listed as 12VDC and >0.5A, you would be good.  The device will pull what it needs up to the designed current of the PSU.  Are these unregulated units different?  Or, do I have this completely wrong?

Brian H

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Re: Arduino ac adapter
« Reply #19 on: June 06, 2015, 06:28:49 AM »

A power supply rated at 12 volts 1 amp. Can supply up to 1 amp of current, at 12 volts. A device using .5 amps would not exceed the 1 amp rating of the supply you chose.

The power transformer in the wall warts voltage varies with the load.

In a unregulated wall wart. The voltage maybe higher than the rating with a light load.  The rated voltage at the specified current and lower if a higher current is being supplied.

The regulated type. Takes the varying voltage and keeps it at the rated output voltage as long as the current rating is not exceeded.

So an unregulated wall wart rated at 12 volts 1 amp. Will be outputting a higher voltage, unloaded or lightly loaded.
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