High Voltage Forum

General electronics => Beginners => Topic started by: Mads Barnkob on October 16, 2019, 07:56:20 AM

Title: Analog Panel Meter Shunt Calculation and Custom Scale Design
Post by: Mads Barnkob on October 16, 2019, 07:56:20 AM
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I needed a 50A current meter for the 1800W induction heater ( https://highvoltageforum.net/index.php?topic=530.0 ), but had none with the proper scaling. I do however have a large box of 1mA blank scale meters, so I decided to do a video on the following topics:

- Learn how to calculate the shunt resistor for your analog panel meter
- Guesstimate the internal resistance of a unknown meter
- Design custom scales if you have a blank meter or want to use a meter for another purpose than its original.

Link to scale-o-matic: http://stiftsbogtrykkeriet.dk/~mcs/Scale.html
Link to Meter from Tonne software: http://www.tonnesoftware.com/meter.html
Title: Re: Analog Panel Meter Shunt Calculation and Custom Scale Design
Post by: klugesmith on October 16, 2019, 05:36:46 PM
Very nice!
Your presentation may serve as a warning to beginners who scrounge a meter with a printed scale of amperes or kilovolts, and connect it directly to a source that matches.

Does the scale-o-matic program do nonlinear scales? 
I needed one on this vacuum gauge readout, for a Convectron 275.  The lines were drawn in Excel, from voltage-to-pressure tables in the manual.  Text added by hand to save time; different versions in the two pictures.