Voltage/Current divider

Causes of Errors in Voltage Dividers and How to Fix Them

In electrical and electronic measurement systems, voltage dividers and current dividers play an important role in processing, distributing, and stabilizing signals before they are fed into measuring instruments.

Common causes of deviations in voltage dividers

A resistive voltage divider is essentially a network consisting of two or more series-connected components, in which the input voltage is reduced according to the ratio between component values. In industrial environments, this type of device is often integrated into specialized modules with solid construction, high stability, and more reliable results compared to self-assembled circuits. Thanks to their optimized structure, resistive dividers help minimize many types of errors during operation.

For example, voltage dividers such as the Tunkia TH0150, HV Hipot GDFR-R100, or Wrindu RDCF-150kV distributed by EMIN all use thermally stable materials and good insulation to reduce errors in industrial environments.

However, in actual operation, deviations may still occur for several reasons. The first is component tolerance. Even high-precision resistors such as 1% or 0.1% still exhibit certain deviations from nominal values. When multiple components with random deviations are connected in series, the overall division ratio can shift, reducing measurement reliability.

Temperature is also a factor that easily causes fluctuations. Every resistor has a temperature coefficient (TCR); when the environment heats up—especially in electrical cabinets operating continuously for long hours component values change with temperature, causing the division ratio to become unstable and deviations to increase over time.

Another common cause is the loading effect. When the divider is connected to a measuring device whose input impedance is not sufficiently high, this load draws current from the output, altering the original division ratio. This is a common design flaw in non-optimized measurement systems and can significantly increase inaccuracies if not accounted for from the beginning.

In addition, for AC signals, frequency is an unavoidable factor. Real components always contain parasitic capacitance and inductance. As frequency increases, these parasitic elements alter the total impedance of the divider network, causing the obtained ratio to deviate from theoretical values. This is particularly important in high-frequency applications or environments with many complex influencing factors.

Solutions to minimize deviations

1. Choose high-precision components

Instead of standard 5% resistors, use higher-accuracy components such as 0.1% or 0.01% with low temperature coefficients, for example 10 ppm per °C.

Prioritize specialized voltage dividers with signal isolation

In industrial environments with high noise and large temperature variations, using dedicated voltage or current divider devices is an effective choice.

Key features to consider include:

• Optical or dielectric isolation to reduce noise and protect equipment.

• Temperature compensation circuits to ensure stability across wide temperature ranges.

• Standardized input and output impedance to minimize loading effects.

2. Correctly calculate load impedance

The receiving device must have an input impedance at least 100 times higher than the total impedance of the divider network.

3. Perform periodic calibration

All measuring instruments must be inspected and calibrated periodically. Most voltage and current dividers include detailed instructions for users to compare deviations and restore the device to its standard state. You may also use professional calibration services to evaluate accuracy and obtain certification when needed.

In addition, choosing a reputable supplier with high-quality products ensures stable operation. EMIN provides a wide range of voltage and current dividers—from standard laboratory devices and high-power industrial models to calibration-grade units—offering comprehensive solutions to help businesses maintain stability in every measurement.