High Voltage Forum

General electronics => Beginners => Topic started by: kamelryttarn on February 10, 2019, 05:46:39 PM

Title: Resistor tolerance?
Post by: kamelryttarn on February 10, 2019, 05:46:39 PM
I would like to user fixed resistors as calibration for a couple of Pt100 and Pt1000-to-4-20mA current loop converters and I was wondering if a fixed resistor (metal film or wire wound) with extremely low temperature coefficient changes value or if it can be considered stable?

For example, if I order a 0.1% resistor specified as 100 Ohm, the actual resistance may vary between 99,9 and 100,1 which isn't much but when translated to degrees Celsius it's roughly -0,2 to +0,2.

My question is: Apart from temperature drift, will a fixed resistor shift in resistance value or can I use a low ppm fixed resistor of any value and type and attach a small note to each stating the corresponding temperature once I have been able to accurately determine that?
Title: Re: Resistor tolerance?
Post by: kamelryttarn on February 14, 2019, 02:27:18 PM
I made this spread sheet to try and visualize what impact the resistor tolerance has when using them as calibration points

https://docs.google.com/spreadsheets/d/1Cs-OpPVZ9Inlz1PG1GYzi1S5flYNSTyw2RnShtDgI1U/edit?usp=sharing

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