Amps and Volts

homer911

Didnt know where to post this question but thought some physics head could advise:

I'm trying to source a cheap replacement transformer for a portable DVD player rated as 9V, 1.3A

The closest I can get to a cheap solution is 12v, 1A.

My (very) limited knowledge of physics tells me V=W/A

Would this 12v, 1A transformer work and not burn out?

Gurgle

homer911 wrote: »

Didnt know where to post this question but thought some physics head could advise:

I'm trying to source a cheap replacement transformer for a portable DVD player rated as 9V, 1.3A

The closest I can get to a cheap solution is 12v, 1A.

My (very) limited knowledge of physics tells me V=W/A

Would this 12v, 1A transformer work and not burn out?

I wouldn't recommend it. Most likely you will end up damaging both the DVD player and the power supply. Of course its possible to build a power supply that will work off either, but this is rarely (never) done in cheap MP gadgets, especially not gadgets with moving parts.

Consider the player as a simple resistive load, then you can use V = IR.

If the player draws 1.3A at 9V it will draw 1.7333A at 12V. This will blow the snot out of a transformer rated for 1A.

Likewise, the components of the Player are calculated for 9V - If you dump in 12V then you're driving 33% extra current into them.

Expect smoke.

Michael Collins

homer911 wrote: »

Didnt know where to post this question but thought some physics head could advise:

I'm trying to source a cheap replacement transformer for a portable DVD player rated as 9V, 1.3A

The closest I can get to a cheap solution is 12v, 1A.

My (very) limited knowledge of physics tells me V=W/A

Would this 12v, 1A transformer work and not burn out?

Definately not! You need the same voltage i.e. 9 V, and a current rating equal to or higher than 1.3 A.

This one here from Peats does the trick, albeit a bit on the expensive side (€25):
http://www.peats.com/cgi-bin/catalog.cgi?view_product=1&id=25879&sid=13&cid=144&scid=313

homer911

Thanks guys - much appreciated

I had been hoping to use this one, which was a bargain, but will keep looking for something more appropriate..

http://www.dealextreme.com/details.dx/sku.15990

homer911

Just to say that I found this website via an Ebay seller and got sorted

http://www.accessory4you.com

They accept PayPal and prices include worldwide shipping, so might be useful to someone

spideog7

Technically it would work if you stepped the voltage down to 9V (9V*1.3A = 11.7W).

But it'd only be worth doing that if you had it lying around, if you're buying it buy the right one.

Bear in mind you only really need to worry about the voltage, so if it's 9V output and and the current rating is higher than 1.3Amps then you're good to go.

EDIT: A bit late, but might help someone else all the same :P