[Elecraft] P3 - powering from the K3 aux plug

[Alan Bloom]

On Wed, 2010-08-18 at 14:16 -0700, Lyle Johnson wrote:
> The short answer is no.

The long answer :=) is that the P3 uses a pair of DC-DC converters to
convert +12V down to the +3.3V and +5V needed by its circuitry.  This
tends to make the input "constant power" meaning that current times
volts is nearly constant.  With a 14V supply, the P3's current is well
under 500 mA.  But with 11V input, the current is close to that value.

The best solution is probably what a couple others suggested:  Use the
K3's switched "12V DC OUT" jack to power a relay which switches the
power to all the other devices.  Then you don't have to worry about it.

Alan N1AL



> 73,
> 
> Lyle KK7P
> 
> > ...The K3 plug says 0.5A max, which is what
> > the P3 draws.  So it looks like its either/or.  Is there
> > enough conservatism in the rating of that power socket to add the P3?
> 
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