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Re: [Amps] What's wrong here- dropping resistor for DC meter?

To: <amps@contesting.com>, "Ed Heimbach" <supermechanic18360@yahoo.com>
Subject: Re: [Amps] What's wrong here- dropping resistor for DC meter?
From: "k7fm" <k7fm@teleport.com>
Reply-to: k7fm <k7fm@teleport.com>
Date: Sat, 9 Jul 2011 06:56:21 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Something is not right.  The meter does not care if the voltage comes 
through dropping resistors or reads directly, so having a string of 
resistors will not affect linearity.

There is another issue with the meter.  First, it could be simply not 
calibrated for dc.  Stupid question, but make sure it is not an ac meter. 
Then, it could be calibrated for a steel panel and not be in one.  Or it may 
not be shielded and not calibrated for a steel panel, but be in one.

Check the calibration with 0-5 volts dc.  Another possibility is that your 
calibrating voltage is off and you are assuming error in the wrong 
instrument.

Finally, there is a free meter scale software program that will allow you to 
make a new meter face.

73,  Colin  K7FM

Or, you can do like we do in airplanes for our compasses and make a meter 
correction chart placed next to the meter.  They are so damned important in 
airplanes that I just got an annual inspection and the inspector noted that 
I needed a compass correction card in plain view even though my compass 
reads correctly all 360 degrees.  Rules are rules.

73,  Colin  K7FM 

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