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AC Adapters

PostPosted: Thu Mar 26, 2009 3:05 pm
by Mathieu Benoit
What are the general rules of thumb when you have a unit that requires an AC adapter and you have a million of them laying around, but not exactly the same spec as the unit. What are your safe alternatives? Also what are the potential dangers that you want to avoid?

Signed,

I just blew up me gear because I'm ill-informed.

PostPosted: Thu Mar 26, 2009 3:11 pm
by Mathieu Benoit
So, I know a couple of things (I think)... First is I check whether the output is AC or DC, second I check polarity if the output is DC because if the polarity is wrong that could lead to damage. I also check to match the voltage, if I can't match it I try to find the closest possible match (while aiming for lower than the voltage indicated if possible.) As far as the milliamps, I've always assume that as long as you are at least as high as what the device is looking for you are fine. I base that guess in my understanding of residential AC power where devices simple take the current that they need regardless of how much current is available on the circuit.

Have I missed anything or confused anything?

PostPosted: Thu Mar 26, 2009 3:24 pm
by Malcolm Boyce
I think you've more or less got it.

PostPosted: Thu Mar 26, 2009 3:30 pm
by Mathieu Benoit
What kind of tolerance should be used when the right voltage isn't in play though? How much is too far off? I know that if I go lower either it works or it doesn't. But going higher, where can I start expecting problems and possible damage? If the voltage is not exactly what is indicated but the device works anyways do I run the risk of any long terms damage?

I guess my personal questions rest in the voltage side of things because it's a little less clear to me. However I thought that this thread is probably a useful topic for a lot of folks out there.

PostPosted: Thu Mar 26, 2009 3:58 pm
by macrae11
I'm sure you can go quite a bit farther, but I try to never be more than +/- 1 V. I've got enough adapters around, and a few universals that I almost never have to break this rule of thumb.

The first two factors are the most important ones. Polarity and AC or DC. Them's the ones that'll put on a purdy smoke show real quick.



Just curious, what did you blow up?

PostPosted: Thu Mar 26, 2009 4:11 pm
by Mathieu Benoit
macrae11 wrote:Just curious, what did you blow up?


Nothing at all. I just wanted start a thread that helped other from blowing up their shit. Alain may be against this because it costs him clients in the shop, but at the same time, I'm sure he doesn't want to deal with consumer-grade surface-mounted gear either. Well at least not more than he has to.