Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: Maximum DC current in Archos FM?
From: Michael O'Quinn (michael_at_oquinn.info)
Date: 2003-06-29


Tom,

Your question tells me that you maybe should not be doing this. I don't
mean that as an insult, but you could very easily fry your Archos Box.

First, do you realize that when measuring current (amperage) you must
insert the meter INTO the circuit, not measure it ACROSS the circuit.
That means that for each trace you would want to measure the current on,
you would need to cut that trace and then use the meter to complete the
circuit.

If you attempt to measure current like you would voltage -- by placing the
probes across the circuit you are trying to measure -- you will get either
(or both) a blown meter (fuse, hopefully) or a blown Archos.

Maybe you already know this -- and I apologize if that is so -- but in
that case I would expect you to also know the answer to your question in
the first place.

To answer your question, I would imagine the charging circuits, voltage
regulator, and the HD would need a heftier meter. Something that can
measure 2 amps (2,000 mA) ought to do the job.

Oh, there might be some AC in the voltage regulator and/or charging
circuits, if they are switching rather than linear. And anything that has
a changing signal is also AC. (Like the digital signals, and the analog
audio signals, and the... Well, lots of things, actually.) Often
electrical circuits have both an AC and a DC component.

Just out of curiosity, what are you trying to accomplish with all of this?

Michael

On Sun, 29 Jun 2003, TP Diffenbach wrote:

>
> I'm trying to purchase a multimeter to trace the circuitry in my Archos FM. I
> assume the current is DC. What's the maximum amperage in the Archos FM? Will a
> multimeter that measures up to 200mA suffice (I suspect not)?
>
> Thanks,
> Tom
>
>



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa