AC DC there the same thing. or DOH!!

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AC DC there the same thing. or DOH!!

I'll start off by saying that I am all too aware of the differences between AC and DC.

Last night I was finishing up a hack. I am putting a USB 2.0/FW 400 bridge and a removable hard drive rack into a old NEC CD-ROM case. So I reached into my bin-o-wall warts and pulled out one that said 12v 1 amp. I said great that will work to test with. Pluged it in and 30 sec later POP. I unplug it and look at the power adapter. The oputput is 12v AC not DC. DOH!! I pull the case apart and it blew one of the CAPs in the voltage regulator.

I plan on replaceing the cap but I am conserned that I may have damaged the voltage regulator. Does anyone know if this is likely or am I just worrying about nothing?

martakz's picture
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Nah, I doupt you've damaged a

Nah, I doupt you've damaged anything other that a few caps.

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There may be SOME hope...

In an ideal DC circuit, you will have the following:
- voltage rectification (which converts AC to pulsating DC)
- voltage regulation (which caps the voltage at a set peak, squaring off the wave some)
- volatage filtering (which 'smoothes out' the wave)
- voltage bleeding and/or filtering (which evens refines the wave-form and spits out different voltages as needed)

AC obviously leaves out the rectification.

If you are certain that the damage is limited to the regulator, you may be okay (and very lucky). Your best bet is to repair the power supply and verify that it is A-1. If it is repaired okay, then you would be best off to try to connect only one device at a time and verify that everything is okay. Do not hook everything up until you do, this way you can be sure that one of your devices is not bad. It would be hateful to have on device be bad and cause a cascade failure in the circuit path. Unless you have an o-scope, your best bet would be to plug it in all alone and see if it is okay.

--DDTM

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Last seen: 1 year 7 months ago
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I replaced the blown cap and

I replaced the blown cap and it works fine. I was planning on replaceing all of the caps but Fry's only had 1 in stock. So I guess I'll just see what happens.

Is it just me or are caps getting expensive. This one was $1.90

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Caps tend to only conduct in

Caps tend to only conduct in one direction, so that probally saved the rest of the board.

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