I want to hard-wire my 9v and 6v scanners to my car but I don't want to use
a cig lighter adapter (unless I can take the thing apart, I am putting the
wiring under my carpet). I am not an electronics guru by any stretch of the
imagination although I can usually solder without starting large fires.

Any tips or schematics for voltage converters to drop my car's 12v down to 9
and 6?

Thanks.

"User" wrote in message
...
I want to hard-wire my 9v and 6v scanners to my car but I don't want to
use
a cig lighter adapter (unless I can take the thing apart, I am putting the
wiring under my carpet). I am not an electronics guru by any stretch of
the
imagination although I can usually solder without starting large fires.

Any tips or schematics for voltage converters to drop my car's 12v down to
9
and 6?

Look for some 3 terminal regulators. Especially if the current is under 1
amp. There are some that will handle more. A number might be like a LM7808
for a 8 volt regulator. All you do is mount them to a heat sink and you
have 3 leads. One to the car's 12 volt source, one to the ground and an
output wire. YOu will also need 2 capacitors, one on the input and another
on the output. They are only about a dollar each.
Some are around that you can adjust the voltage with a resistor or two.

If you have a capacitor on the output of any linear
VR IC you must include a diode in series with the
input +V to protect the VR IC against reverse
current tht will result from removing power with any
DC continuity to ground. LM78xx and LM317 are
tuff ICs but I destroyed several before I learned
about the diode. A 1n4002~1n4008 will work fine
and they are dirt cheap. It iaslo a good idea to put
a 2 or 3 amp fuse in seriers for some overcurrent
protection.

Terry

Okay, here's what I did for my GPS unit that is 4.5 volts. I went to
the local Wal-Mart and found some $1.00 clearance car charger/adapters
for cell phones. Most of them that I saw showed the voltage and
(milli)Amps. I found one that was the correct voltage and had enough
Amps to cover my device. I cut the ends off and wired it in with my
preferred connectors. Once it worked, I bought another just for
backup.

Good luck.



On Thu, 30 Dec 2004 21:27:34 -0700, "User" wrote:

I want to hard-wire my 9v and 6v scanners to my car but I don't want to use
a cig lighter adapter (unless I can take the thing apart, I am putting the
wiring under my carpet). I am not an electronics guru by any stretch of the
imagination although I can usually solder without starting large fires.

Any tips or schematics for voltage converters to drop my car's 12v down to 9
and 6?

Thanks.


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