Voltmeter:
A simple DC voltmeter could be constructed through placing a resistor (RS), known as a multiplier, within series with the ammeter meter movement, and marking the meter face to read voltage display in the figure. Voltmeters are linked in parallel along with the load (RL) being measured.
![899_Voltmeter.png](https://www.expertsmind.com/CMSImages/899_Voltmeter.png)
Figure: Simple DC Voltmeter
Whenever constructing a voltmeter, the resistance of the multiplier has to be determined to measure the desired voltage. By the Equation(14-1) is a mathematical representation of the voltmeter's multiplier resistance.
V = ImRs + ImRm
ImRs =V - ImRm
Rs = V/Im -Rm (14-1)
where
V = voltage range desired
Im = meter current
Rm = meter resistance
Rs = multiplier resistance or series resistance