The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "Spehro Pefhany"
Subject: Re: Digital Meter Scaling Question
User-Agent: tin/pre-1.4-19990216 ("Styrofoam") (UNIX) (Linux/2.2.14 (i586))
Date: Mon, 07 Oct 2002 18:42:26 GMT
NNTP-Posting-Date: Mon, 07 Oct 2002 14:42:26 EDT
The renowned Ed Edmondson wrote:
> I have a Datel panel meter rated at 2 volts full scale and I am measuring a
> voltage in the 200 mV full scale range. Is there anyway to us an op amp to
> increase the measured voltage to operate this meter and obtain better
> resolution? The meter works OK on the 2 volt range but all the readings are
> 0.XXX volts instead of X.XXX volts.
Typically the reference is just dropped to 100mV from 1 volt, and a couple
changes are made to the auto-zero and integrating components and presto,
100uV resolution with less than a count of noise and no appreciable zero
To use an op amp with a 10:1 gain is possible, easy even, but you'll have
to pick the op-amp carefully (Vos and TCVos and maybe Ib) and take into
account the common mode range of the op-amp. Easiest to use (not cheapest)
would be a rail-to-rail chopper op amp, which would be much better than
"it's the network..." "The Journey is the reward"
email@example.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup