I was studying avometer, and came across this paragraph which I find

[uzair_ha91]

I was studying avometer, and came across this paragraph which I find confusing: "The voltage measuring part of the avometer is actually a multirange voltmeter. It consists of a number of resistances each of which can be connected in series with the moving coil galvanometer with the help of a switch called the range switch. The value of each resistance depends upon the range of the voltmeter which it controls..."
I thought that the resistances make up the range, so why does it say that their values depend upon the range? What range are we talking about here? Please clarify...

 

[Darryl]

Im guessing, but I think they would be referring to the FSD for full scale deflection current of the moving coil galvanometer.

The series resistance will scale it's current based on I = V/R. V is the measured Voltage, and R is the total resistance of the moving coil galvanometer and the range resistance value.

This brings up the term "Ohms per volt" which is a measure of "goodness" of (mainly) analogue meters.
The AVO is a classic instrument rugged and accurage and a pleasure to use.

 

[charng]

It is understandable that this paragraph may be confusing at first glance. Allow me to provide some clarification on the topic of avometers and their voltage measuring capabilities. The avometer is indeed a multirange voltmeter, meaning it has the ability to measure voltage at multiple ranges. This is made possible by the use of resistances, which are connected in series with the moving coil galvanometer through a range switch. The value of each resistance determines the range of the voltmeter that it controls. In other words, each resistance is responsible for measuring a specific range of voltage. Therefore, the values of the resistances do indeed depend on the range of the voltmeter they are controlling. I hope this helps to clarify any confusion you may have had.