|  Phaedrus420 | Jan 2, 10:46am | This is a copy|paste from my page, hopefully this is a better way to find what I need.
I'm also posting this in Hack
Ok, internet, I need help.
Seriously
So I've got one of those FM transmitters to get audio from [device] to [radio].
It eats batteries.
I want to power it from 'my' truck's wiring.
How do I turn 11-14.5 volts into 3 volts?
I'm looking at the LM117, but wouldn't know how to use it.
I've seen the schematics and whatnot, but they just say Rv and Cv, and it is as yet beyond me to figure out what values I need, except by using a variable resistor for guess and check.
Also, will the switching make noise on the transmitter?
How about running the transmitter from the 5v on my USB port?
Will it blow up, or just put out a stronger signal?
I promise that once I get it up and running (There's more to the rig I have in mind, but it's secret for now), I'll make a HOWTO for instructables or something.
Maybe I'll just go to Radio Shack and ask them.
That was a joke.
"We have answers."
As long as your are asking about cell phone plans.
Even then, good luck.
Thanks. |
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Engineering → Discussion