Posted by KaraS on May 27, 2005, at 16:30:09
In reply to Re: rethinking my answer, posted by so on May 27, 2005, at 9:31:33
> > So is the consensus now that this is too risky because we're not sure of polarity? I don't understand why you would need an AC adapter where input is AC and so is output. I thought the whole point was to adapt between AC and DC? (but what do I know??) And, if the output wasn't in the right form then why did it work when I tested it?
>
> Some of this gets into electrical engineering (and actuarial) questions beyond me unless I conduct considerable research. If you can afford the 15 bucks, the new adapter might be the surest shot. Otherwise:
>
> The adapter does a couple things - first it serves as a transformer - reducing output voltage from 120v to 12v. We're pretty sure your spare covers that part.
>
> Some adapters convert from AC to DC, but not all. Some circuits just need the lower voltage, and there are AC to AC transformers out there that only reduce voltage. It's beyond me to say what would be harmed by using AC voltage in any particular DC circuit. The broad group of risks to consider would be A. fire, B. damage to the device supplied voltage and C. damage to the transformer itself. But these are just broad groups -- I can't rule them in or out or say how much risk.
>
> Then the other risk involves reversed polarity. Technically, I can't rule out fire as among the broad group of risks for reversed polarity, but instinctively and based on experience, damage to the equipment might be the only practical risks, then I can't honestly assess those risks without A. knowing something about the devices and B. studying electrical engineering.
>
> If the device -- the antena -- works with the spare, that would seem to sugget it works. But we don't know it's not slowly damaging something. Then it becomes a matter of how much is the antena worth to you to risk finding out how long it will hold up. I have had devices fail immediately upon being supplied with current when the polarity is reversed. So your asking advice from somebody who has destroyed devices for lack of care or knowledge. And I would tend to rule out fire as a risk if the voltage is right, but I just can't based on the little I know.
OK, thanks again. I'll pay the extra $15. It's better to be safe than sorry. Actually, it's not just $15, because I have other things to replace because of that little devil... but again, better safe than sorry.Take care,
Kara
poster:KaraS
thread:503045
URL: http://www.dr-bob.org/babble/social/20050525/msgs/503770.html