12VDC/2A power adapter to power two systems?

[perplexabot]

Hey!
So I have a raspberry pi that uses 5V/1.2A and a LCD monitor that uses 12v/0.2A. I would like to power both using a single wall power outlet. I found a power adapter that converts 100-240VAC/50-60Hz/1.2A to 12VDC/2A.

I was wondering if it is as easy as cutting off the connector on the other side of the adapter, and using the +12/-12 wires to power the LCD (which I'm sure would work), then I would also tap the +12/-12 wires to a LM317T so that it outputs a regulated voltage of 5V (to the pi).

Will this work?

Thanks.

 

[davenn]

I was wondering if it is as easy as cutting off the connector on the other side of the adapter, and using the +12/-12 wires to power the LCD (which I'm sure would work), then I would also tap the +12/-12 wires to a LM317T so that it outputs a regulated voltage of 5V (to the pi).

Will this work?

yup ... ensure the 317 is well heat sunk ... it's going to dissipate a lot of watts of heat
namely 7 x 1.2A = 8.4W

edit ... also note that @ 1.2A that is right near the max for the LM317 ... best to use the TO3 case not the TO220 case version

 

[perplexabot]

yup ... ensure the 317 is well heat sunk ... it's going to dissipate a lot of watts of heat
namely 7 x 1.2A = 8.4W

edit ... also note that @ 1.2A that is right near the max for the LM317 ... best to use the TO3 case not the TO220 case version

Thank you for the quick reply! Great to hear it is that simple! Unfortunately now I have to solder together a new circuit for the TO3 instead of using an older circuit i had with the TO220.

Oh well, shouldn't be too bad. Thanks again.

EDIT: DAMN! Those TO3's are 40 bucks on digikey!

 

[davenn]

EDIT: DAMN! Those TO3's are 40 bucks on digikey!

seriously ? ... I pay around $2.50 locally for them

edit ... or you could do the eBay buck convertor thing much more efficient and you need not worry about the heatsink AU$8.00

http://www.ebay.com.au/itm/Adjustab...175084?hash=item27ec1ef02c:g:uuwAAOSwGvhUB~Mx