Re: 12v down Cat5 again

[Robert Kearns <robkearns@xxxxxxxxx>]

Hi David,

Try the following site, it has a voltage drop calculator which also shows
power dissipation: http://www.gweep.net/%7Esfoskett/tech/poecalc.html

I has a camera which requires up to 1 amp running over cat5 using two pairs
with no problems.

Rob

On 1/9/06, David Chapman <david@xxxxxxx> wrote:
>
> Yes I know it's been discussed before but I can't find any consensus
on
> the
> figures.
>
> Although it has batteries my WM968 weatherstation needs 12v - mainly
to
> power the backlight behind the LCD display which comes on when you
touch
> it.
>
> Got the meter out and it's 12v and needs 10mA most of the time
increasing
> to
> 150mA for the 10 seconds or so when backlight is on. Although it's
Cat5
> I'm
> sending good old RS232 down it to the Com port of the PC - I think
just
> pins
> 2, 3 and 7 so should have potential to double up the available pairs
to
> supply 12v if necessary, distance is about 10 metres.
>
> Be great to feed the 12v from node zero and avoid the black box. I
would
> of
> course put a fuse in to protect the cable but is an occasional 150mA
> asking
> too much ?
>
> David C
>
> ps I was talking about RS232 during Christmas after the Spitting Image
> tribute with some friends who don't go back further than USB. Anyone
else
> remember the Spitting Image tribute song to the "RS232, RS232, RS
two
> thirty
> two interface lead" ?
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>


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