Path: utzoo!utgpu!cunews!software.mitel.com!grayt
From: grayt@Software.Mitel.COM (Tom Gray)
Newsgroups: sci.electronics
Subject: Re: RE Descrambler
Message-ID: <6548@healey>
Date: 15 Feb 91 14:02:02 GMT
References: <1991Feb9.233031.25283@sactoh0.sac.ca.us> <17660151@hpfcdj.HP.COM>
Organization: Mitel. Kanata (Ontario). Canada.
Lines: 32

In article <17660151@hpfcdj.HP.COM> myers@hpfcdj.HP.COM (Bob Myers) writes:
>>I've finally decided to build the descrambler and have a quick
>>question.  What does NPO stand for on capacitors?  Is there
>>anything I should know before I start building this thing?
>
>"NPO" stands for "Negative-Positive-Zero" (if it stands for anything), and
>basically means a ceramic capacitor whose value changes very little with
>temperature.  (I believe that "C5G" or something like that is the present

I agree with Bob's statements here but maybe there is a need for a
small qualification. I too thought that NPO was a classification
of the temperature rating of a ceramic capacitor.

However.

I was told in no uncertain terms that NPO is a TYPE of ceramic
used for capacitors. Examining a capacitor catalogue showed that this
was the case. In short NPO capacitors have a low temperature coefficient
but not all low temperature coefficient capacitors are NPO.
I previously worked for a large company where the terms Z5U, Y5V
NPO etc were used to describe caps of all types. It came as
a complete surprise to me to find that NPO pertained to only
one type of ceramic.

A great electronic trivia question - stump your firends. 
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