Split DC adaptor for 12v and 5v

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lexdiamond20

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Joined 2013
#1
I have a BT module that will be integrated into my setup. The problem im running into is that it requires 5V as opposed to the 12 volts coming from my DC adaptor which will power my amp. Would my best bet be aquiring the following

Amazon.com: DC Female to 4 Male Power Splitter Cable for CCTV: Camera & Photo

and then using one cable to power the amp and utilizing a 12v to 5v converter such as this

Amazon.com : HOSSEN® DC/DC Converter 12V Step Down to 5V 3A Power Supply Module : Electronics

on the other cable going to the BT module?
 
#4
sofaspud said:
That looks like it would work. I don't know what a BT module is. Those Amazon items aren't expensive, but I would DIY it with a 7805-type regulator and an appropriate coax power plug spliced into the 12V line.
Click to expand...

Thanks. Though, if using the voltage regulator, would I need a heatsink in pulling .05 amps through it? I tried using a calculator for this and couldn't get an answer.
 
#6
sofaspud said:
That looks like it would work. I don't know what a BT module is. Those Amazon items aren't expensive, but I would DIY it with a 7805-type regulator and an appropriate coax power plug spliced into the 12V line.
Click to expand...

Just realized it would be cheaper to use USB car chargers as they already contain the voltage regulators and everything else I need. I can also pick them up locally at Microcenter for about $2 a piece. The Amazon items I previously linked ran up the price with shipping.
 
#7
Yes, that's a good idea... a cheap off-the-shelf 12V->5V converter... if you don't have voltage reg components at hand.
BTW,
I tried using a calculator for this and couldn't get an answer.
Click to expand...
This is super easy:
Just take the voltage dropped across the regulator (in this case 7V) and multiply it by the current through it (in this case 50mA), which gives
(12-5)*0.05=350mW
You'll find in the 78xx datasheet that this is little heat dissipation for a TO-220 package.
 
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