How to use the voltmeter multiplier resistor calculator
Find the series resistor that extends a meter movement to a higher voltage range. Enter meter resistance, meter full-scale current, desired full-scale voltage in the fields above; the series resistor, total resistance are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “voltmeter multiplier”, “extend voltmeter range”, “series resistor for meter”, “calculate voltmeter multiplier resistor”, “find series resistor”.
Formula
Variables
- Rm — Meter resistance (Ω)
- Im — Meter full-scale current (µA)
- Vr — Desired full-scale voltage (V)
Worked example
With meter resistance = 1000 Ω, meter full-scale current = 50 µA, desired full-scale voltage = 10 V, the calculator gives series resistor ≈ 199 kΩ; total resistance ≈ 200 kΩ.
Frequently asked questions
What is the voltmeter multiplier resistor calculator used for?
Find the series resistor that extends a meter movement to a higher voltage range. It helps with questions such as “voltmeter multiplier”, “extend voltmeter range”, “series resistor for meter”.
What is the formula for the voltmeter multiplier resistor calculation?
Series resistor (kΩ) = (Vr / (Im × 1e-6)-Rm) / 1000. Total resistance (kΩ) = [Series resistor]+Rm / 1000. Here Rm is meter resistance (Ω), Im is meter full-scale current (µA), Vr is desired full-scale voltage (V).
What inputs do I need for the voltmeter multiplier resistor calculator?
You need meter resistance in Ω, meter full-scale current in µA, desired full-scale voltage in V. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the voltmeter multiplier resistor calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the voltmeter multiplier resistor result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.