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Discussion Starter #1
You feed a DC signal to an AC/DC transformer? I'm trying to find a way to get my MP3 player integrated into the car so that I don't need to pull it out to charge it. I'd like to avoid purchasing and isntalling an automotive inverter for this purpose. The transformer specs are as follows:

Creative
model: TESA9B-0501800-A
P/N: AD20000002420
Switching Adapter
Input: 100-240V @ 50-60 Hz @ >.28 Amps
Output: 5v @ 1.5A

So what will it do?
Produce no output
Damage the Transformer
Produce a damaging output
Produce a nonharmful output

It's certainly not going to work... I guess I need to figure out a voltage regulating circuit and build my own adapter... Voltage regulation.. easy. Current regulation...hmmm. anyone got the circuitry know-how? I guess the key lies in determing the charging resistance of the device.

Any help would be appreciated. Btw: this is a lithium-ion battery ill be charging so i need to be 100% sure...not even a replaceable battery on this particular player.
 

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Discussion Starter #3
..useful.

Anyway, i found this voltage/current regulator... specs on it seem to indicate it should work- goingto correspond with the company and verify. the only thing concerning me is that it says its input voltage is 40v, but allows up to 60 before it will blowout. Now, im not sure if that means the normal max is 40, but spikes of 60 are okay, or if 40v is required to make it work. I don't see any reason that i would need more than the output voltage to make it work.

http://www.selectronic.fr/includes_selectronic/pdf/Thomson/L200.pdf
 

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I'm glad I could help. :-D

Why don't you get a car adapter and take it apart to hardwire it to the lighter or something? I've seen that done and works pretty well. Especially if you can solder on some connectors.
 

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well, if you buy a car charger for it, you could splice the car charger into the cig lighter, and then custom mount a hold or something for the mp3 player.


i do believe i have a link....ok maybe not. but badgerbiker did something like this. search for it, and you'll find it.
 

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I feel like I'm in the Christmas Story, "You'll shot your eye out, Kid!"
You'll likely fry the transformer with direct current.
 

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Discussion Starter #7
Bah. I suppose i should just shell the cash instead of over-complicating everything... Honestly id sorta forgotten the possibility of just buying a car adapter ;p Its the engineer in me i guess. lol.
 

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what MP3 player do you have, that you can't buy a car charger for?
 

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You can buy a charger that would give that would work. For example, my Sidekick is a 5v 1A charger. You could use that, though it won't charge as well.
 

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sooooooooo what'd you decide?
 

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Discussion Starter #15
sry, went and played some online pool ;p

Im either going to try and get the actual creative car charger (it appears to be the easiest to modify to hardwire in) or im going to install and auxillary power plug in the lower compartment of the center console and get a cheap 12$ adapter off ebay.
 

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You've probably finished this project already, but I thought I'd answer your question:

[quote author=Zorminster link=topic=66337.msg1137913#msg1137913 date=1168221116]
You feed a DC signal to an AC/DC transformer? [Snip]
[/quote]

You will get no output from a transformer on DC. Transformers rely on the AC to produce a magnetic flux in the transformer core, at steady state DC you will get no flux, and hence no output.
If you're using a wall-wart inverter (like the boxes you plug directly into the wall) you may be able to rip it apart and bypass the transformer part and hook in before the voltage regulator. Depending on the design of the circuit this could get you the output you want.
If an adapter is only $12 tho it's probably not worth your time to try and modify the AC/DC inverter.
 

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[quote author=Zorminster link=topic=66337.msg1137943#msg1137943 date=1168221936]
Bah. I suppose i should just shell the cash instead of over-complicating everything... Honestly id sorta forgotten the possibility of just buying a car adapter ;p Its the engineer in me i guess. lol.
[/quote]

WHAT?! If you had an engineer in you, you would have known better to ask what would happen if you fed 12v DC into an AC Transformer..... comon man....
 
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