how to reduce voltage
Printed From: the12volt.com
Forum Name: Vehicle Wiring Information & File Requests
Forum Discription: Request Car Alarm, Car Stereo, Cruise Control, Remote Starter, Navigation, Mobile Video, and Other Vehicle Specific Wiring Info, Manuals, Tech Tips
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=32725
Printed Date: June 03, 2024 at 9:16 AM
Topic: how to reduce voltage
Posted By: edlojeski
Subject: how to reduce voltage
Date Posted: May 25, 2004 at 3:48 PM
i've got a 9v device which i've used successfully via a cigarette lighter adapter from radio shack (12v -> 9v), but now i would like to hard-wire it in. my jeep has the second accessory plug so i was thinking of just splicing into that, but i'm not sure what i need to reduce the 12v to 9v in place of the huge adapter.
any insight appreciated.
thanks.
Replies:
Posted By: xetmes
Date Posted: May 25, 2004 at 5:37 PM
depends on the current draw, easiest was would be a discrete voltage regulator, just make sure it is not always powered as it will waste power...
Posted By: edlojeski
Date Posted: May 25, 2004 at 5:52 PM
can you elaborate? my knowledge is limited to basics, i.e. switches and relays...
where could i find this regulator? how/why would it waste power?
fyi, it would be for a wireless video receiver, so not sure what the draw is. i guess i could put it on the same relay as the camera switch...
thanks.
Posted By: xetmes
Date Posted: May 25, 2004 at 9:30 PM
the easiest way may just be to buy a female cigarette receptical and just use the adapter you already have, and hardwire it in. A voltage regulator is a small 3 terminal device that can provide a voltage reduction, many different kind exist and many can supply 1A to 1.5A. The cheapest ones will waste a few milliamps without any load... If you want a regulator they can be purchased at most any electronics stores (maybe radio shack, hopefully...) or online at places like mouser.com or digikey.com
Posted By: edlojeski
Date Posted: May 26, 2004 at 12:18 PM
hmm... i was hoping not to have to go the adapter route, just in terms of space behind the console.
somebody else recommended a transformer (something about more coils on one side than the other).
i'm just looking for the "guts" inside one of those cigarette lighter adapters-- what do they use?
thanks.
Posted By: xetmes
Date Posted: May 26, 2004 at 1:02 PM
you could use a transformer, it will not be very simple though since you will have to oscillate the DC voltage, step it down and rectify it, it would not be worth all the work. I would assume cig adapters use a linear regulation device to save cost. A voltage regulator is probably your best bet, as long as you are not drawing more than 1 amp...
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