From: "Tom Faloon"
Subject: Re: Digital Meter Scaling Question
Date: Wed, 9 Oct 2002 13:03:52 +0100
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NNTP-Posting-Date: Wed, 9 Oct 2002 12:39:49 +0000 (UTC)
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The solution to your question may seem simple in principle, (it's just a non
inverting OP Amp, and it could be knocked together in ten minutes) but
chances are, the results would be disappointingly inaccurate. It needs
careful component selection and design, and this depends on your
requirements. You won't get the help you want unless you specify the
requirements. (No guarantee even then, since it may take several hours work.
Newsgroups are great for quick answers to specific questions, with 5 minute
answers, but your problem raises a host of questions, and few folk will have
the time, or inclination to do your design for you.)
So, help someone to help you. You need to answer the following, at least to
What % accuracy do you want?
What is the source impedance of the voltage to be measured?
Will the system be battery operated, (If so, the amp may need to draw low
If used, is the battery voltage/type important?
If not battery operated, what power supplies are available, or what would
you like to use?
What is the temperature range you intend to use it in?
Is cost important?
Do you already have one or more preferred OP Amps in mind?
What is the panel meter part number? and where can one find a data sheet.
(I know you specified that already, but few folks are going to plough
through a dozen messages to find it! Put it all on one page, and hope for a
The meter I am using is a 5 volt LED panel meter. The part number is Datel
DMS-30PC-0-BS. The datasheet is available at www.datel.com.
Ed Edmondson wrote in message
> I really still need your help? Anyone have any amp suggestions?
> Ed Edmondson
> Alamosa, CO