ttg fixed supply

ned1 · Posted: Mon Jul 04, 2005 9:37 pm Post subject: ttg fixed supply

Hi, I would like to fix a supply in my car without using the lighter (to big with wires in the way), with a in line fuse, switch and transformer, can you get some sort of car adaptor and if so where from.
Thanks
ned

Andy_P · Posted: Tue Jul 05, 2005 1:02 am Post subject:

As you've mentioned a transformer, you've not fallen into the first trap that several people on the forums have - assuming you can just wire a power plug into the car's wiring. 12 volts up the TomTom's 5 volt input = "bang"

However, what you DON'T want is a transformer! Transformers only work with A.C. current.
You WOULD use one in, for example, the TomTom mains adaptor, where it is used to reduce 120/240 mains voltage down to a few volts A.C. and then additional components (rectifier diodes, capacitors and possibly a regulator I.C.) are used to convert the A.C. into 5V D.C.
But in the car you have D.C. already, so it only needs to be put through a regulator circuit to reduce it down to 5V.

As this circuitry is what is already present in the cigar lighter plug, the easiest way (IMHO) is to buy an extension lighter socket cable, cut off and discard the plug end and wire the lead into the car electrics. Then just plug the TomTom adapter into the new socket and lose the whole lot behind the dashboard.
That's how I'll be doing it when I stop being so bone idle!

Andy_P · Posted: Tue Jul 05, 2005 1:11 am Post subject:

Forgot to mention - you can get extension leads from Maplins for £2.99 or just a cable mounting socket for 99p. Halfors probably do something similar, too.

ned1 · Posted: Tue Jul 05, 2005 9:21 am Post subject:

Thanks for that Andy,
Sorry to a pain but have you a part # for it to make sure I get the right bits.
Ned Wink

ned1 · Posted: Tue Jul 05, 2005 9:30 am Post subject:

When you say "cut off and discard the plug end" are you talking about the
part on the ttg that plugs into the lighter or the other way round !!
please give me a idot's guide Embarassed

rkm_hm · Posted: Tue Jul 05, 2005 1:05 pm Post subject:

ned1 · Posted: Tue Jul 05, 2005 2:44 pm Post subject:

Ok great, got it, thanks Roger and Andy
Rolling Eyes

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