Re: Plug in power voltage?

["Matt Blaze" matthew.blaze]

On Aug 21, 2009, at 7:07, Klas Strandberg wrote:

> Hi folks!
>
> It would help me and users if I better knew about the plug in power
> voltage that different recorders provide.
>
> This is the test:
>
> 1/ Connect a potentiometer and a mA meter in series between input
> and ground.
> 2/ Set the potentiometer so that the mA meter shows 0,5 mA.
> 3/ Measure the voltage between input and ground.
>
> For the moment I am specially interested in the voltage that Sony
> PCM-D50 provides at a given current, like 0,5 mA.
>
> Klas.
>
>
>


And adding the Nagra ARES-MII to the list:

To summarize (view in a monospace font):

MODEL           V (unloaded)    V @ 0.50 mA    Load (Ohms)
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D
Sony D50          2.82            0.52           1030
Zoom H4n          2.84            1.82           3606
Olympus LS10      3.02            1.93           3828
Nagra ARES-MII    2.81            1.78           3580

The Sony remains an outlier here.

Again, my 0.50 mA current adjustments were only approximate -- I set
the load resistor to get as close to 0.500 mA to flow as I could, but
really got only within +/- 1 % or so.  So the loaded voltage isn't
exactly R * .0005, because the current wasn't exactly 0.5000 mA.  It's
just close.  Ohm's law still applies in Philadelphia, in spite of what
the numbers above might suggest!

V measurements were done with a recently calibrated Fluke 189.
Current was measured with a Fluke 289, also recently calibrated.

-matt


mab blogs at http://www.crypto.com/blog/