[TriEmbed] I2C range extension

[Carl Nobile]

Pete,

I read the spec on Wikipedia
https://en.wikipedia.org/wiki/Power_over_Ethernet

The spec is defined by power rating primarily. At the bottom of the page it
shows current. It looks like these currents are minimal currents not
maximal. But, as you said, based on wire length and if power is held steady
the wire resistance will kill the actual delivered current.

~Carl


On Fri, Oct 2, 2015 at 9:30 AM, Pete Soper <pete at soper.us> wrote:

> Thanks for the correction. So 300ma through each of the two power-carrying
> pairs. But if we recall Brian's Ohm's Law talk and look at the voltage drop
> across 26 gauge wires we see where the limit really comes from. The voltage
> drop is spectacular for even a few dozen feet.
>
> -Pete
>
>
> On 10/02/2015 09:06 AM, Carl Nobile wrote:
>
> Pete,
>
> I just checked, there are two specs PoE and PoE+. The first one has a
> maximum current of 300mA and the second one has a max of 600mA. Obviously
> both are too low. Too bad, this was a good idea.
>
> ~Carl
>
>
> On Fri, Oct 2, 2015 at 8:36 AM, Pete Soper via TriEmbed <
> triembed at triembed.org> wrote:
>
>> WIthout a switching converter on the other end the wrong order of
>> magnitude of current is available:
>>
>>   https://en.wikipedia.org/wiki/Power_over_Ethernet#Power_capacity_limits
>>
>> On 10/02/2015 07:02 AM, Jim Ray via TriEmbed wrote:
>>
>> Has anyone modified Raspberry Pi to use PoE for power? Using standard
>> Ethernet to drive a communications sub system based on another Raspberry Pi
>> that has the requisite i/o and processor makes a lot of sense to me.
>>
>>
>> -Pete
>>
>> _______________________________________________
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>>
>>
>
>
> --
>
> -------------------------------------------------------------------------------
> Carl J. Nobile (Software Engineer)
> carl.nobile at gmail.com
>
> -------------------------------------------------------------------------------
>
>
>


-- 
-------------------------------------------------------------------------------
Carl J. Nobile (Software Engineer)
carl.nobile at gmail.com
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