schottky diode again..

From: Richard Erlacher <edick_at_idcomm.com>
Date: Wed Nov 3 16:49:33 1999

If you have a diode of any kind which behaves more as a resistor and less as
a diode, i.e. it measures more or less the same in both directions, though
differently on different settings on your DMM, I'd say it's broken. The
reason for all the discussion about batteries is that a set of batteries for
a typical notebook costs only a bit less than $200 for a cheap one, and it's
useful to know whether the notebook works before buying a new battery pack.
Most of them don't work with no battery at all, though some do. If there's
something wrong with your diode and the diode is in the charging circuit,
with behavior like you've described, it will discharge your battery and
subsequently into deep discharge, which will permanently and irrevocably
damage NiCd and NiMH batteries.

A schottky diode is simply a diode. It has doping different from a typical
silicon diode, hence has a lower forward voltage, hence dissipates less
power than a silicon diode at the same current. If it has measurable
resistance cathode to anode and anode to cathode which is about the same,
it's no longer acting as a diode.

Dick

-----Original Message-----
From: jpero_at_cgocable.net <jpero_at_cgocable.net>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Wednesday, November 03, 1999 3:30 PM
Subject: schottky diode again..



Sheesh, that topic wandered off the diode discussion!

Snip!

The important thing I wanted to hear about is how schottky
diodes reacts if good and what it's like when bad or sick on a DMM
with different resistance scale settings used, diode test also seems
says "good" but I know it's very low current also low voltage so that
would usually not screen out sick diodes. That why I used resistance
ranges just to be sure.

Yes, I pull diodes and transistors out for checks to be sure.

Ingore the battery thing please. I'm more concerned getting the
notebook going.

Thanks.

Wizard
Received on Wed Nov 03 1999 - 16:49:33 GMT