What Is a Capacitive Voltage Divider?

A voltage divider is a type of passive linear circuit generating an output voltage that is a fraction of the input voltage. It’s possible to create these circuits using fixed-value resistors or reactive components. 

The Stangenes offering of capacitive voltage dividers are specially created for diagnostic and monitoring applications, also commonly referred to as voltage monitors. These components can take a multi-kilovolt signal and output a low voltage signal that can be read on oscilloscopes and other monitoring devices. 

Introduction to Capacitive Voltage Dividers

When deciding whether to use a capacitive voltage divider, understanding how it works can help.

Typically, when two interlinked circuit elements form a series, the input voltage divides through the elements. When circuit elements are interlinked but parallel, the electrical current will also normally split through the components. As a result, series circuits operate under the voltage divider rule while parallel circuits operate under the current divider rule.

Also called the potential divider rule, the voltage divider rule is crucial for analyzing circuits by helping calculate each element’s individual voltage. 

The elements of the circuit will dictate the category of the voltage divider rule, particularly these three categories:

• Capacitive voltage divider
• Resistive voltage divider
• Inductive voltage divider

How Does a Capacitive Voltage Divider Work?

These devices work by connecting two capacitors in a series with a resistor. One capacitor receives the input voltage, while the other is grounded. You can modify the voltage ratio between both capacitors by changing their resistance values.

The electrical current travels through the divider via the resistors, forming an electrical field in the process. This field influences each capacitor’s charge and thus alters their respective voltages. The benefit of this operation is the ability to precisely control circuit voltage levels without any physical adjustment to the circuit elements.

Advantages and Disadvantages of a Capacitive Voltage Divider

Capacitive voltage dividers offer several key benefits and disadvantages.

Some of the advantages of these devices include:

• Reduced resistance — Compared to resistors, capacitive voltage dividers have less resistance, meaning less dissipation of waste energy as heat.
• Optimized accuracy and precision — Using a series of capacitors offers superior accuracy and precision compared to resistors and other dividers.
• Low power consumption — Voltage divider capacitors need minimal power to function, which is why they’re ideal for low-voltage applications.

Meanwhile, some potential downsides of using capacitive voltage dividers could include:

• More expensive than other types of dividers — Lower voltage capacitive dividers can be more costly than other types of dividers. Higher voltage resistive dividers can also be expensive.
• Increased complexity — To get the best results from these dividers, it’s critical to carefully calculate and design them, which can limit their use in some applications.
• Sensitivity to temperature fluctuations — Ambient temperature can significantly influence the divider output, potentially leading to inaccuracies. This is why Stangenes uses temperature-compensating components to reduce this effect.

Capacitive Voltage Dividers from Stangenes Industries 

Depending on your application, you may benefit from the use of a voltage divider capacitor. Stangenes Industries offers capacitive voltage dividers as well as compensated resistive voltage dividers in nearly any size or shape to meet your unique specifications. Our voltage dividers can be used for pulse voltages up to 800 kV, and we can custom-make units suitable for higher voltages. 

To learn more about our offerings or get started on an order, request a quote today!