Clamping Voltage

Definition of Clamping Voltage

Clamping voltage refers to the maximum voltage level that a surge protector, such as a transient voltage suppressor (TVS) diode or varistor, allows to pass through to the protected device when a voltage spike occurs. It is the voltage level at which the surge protector starts to divert the excess current to the ground to maintain a safe voltage for the connected equipment. A lower clamping voltage generally provides better protection for sensitive electronic devices.


The phonetics of the keyword “Clamping Voltage” can be represented as:K-L-Æ-M-P-IH-NG V-O-L-T-IH-JHere, each letter represents the following sound:K – /k/ as in ‘key’L – /l/ as in ‘light’Æ – /æ/ as in ‘cat’M – /m/ as in ‘moon’P – /p/ as in ‘pole’IH – /ɪ/ as in ‘bit’NG – /ŋ/ as in ‘sing’V – /v/ as in ‘victory’O – /oʊ/ as in ‘go’L – /l/ as in ‘light’T – /t/ as in ‘time’IH – /ɪ/ as in ‘bit’J – /dʒ/ as in ‘jump’

Key Takeaways

  1. Clamping Voltage is the maximum voltage permitted through a surge protector, ensuring that connected devices are undamaged during voltage surges.
  2. Lower clamping voltage indicates better protection, as it significantly reduces the amount of excess voltage reaching the connected devices.
  3. Choosing a surge protector with an appropriate clamping voltage is crucial for safeguarding sensitive electronic equipment from potentially harmful electrical surges.

Importance of Clamping Voltage

Clamping voltage is an important technology term as it refers to the maximum voltage allowed to pass through a surge protection device, such as a surge protector or transient voltage suppressor (TVS), before it engages and diverts excess voltage to the ground.

In essence, it ensures the safety and protection of sensitive electronic equipment and devices from potential damage caused by voltage surges or spikes.

Having a lower clamping voltage generally provides better protection.

Thus, understanding and selecting the appropriate clamping voltage becomes crucial for maintaining optimal functionality, longevity and reliability of electronic systems, preventing costly repairs or replacements while safeguarding valuable data.


Clamping voltage is a critical parameter in the realm of surge protection devices, as it serves to protect sensitive electronic equipment from voltage spikes and transient overvoltages that can cause severe damage. These voltage fluctuations often occur due to events such as lightning strikes, power outages, or when large appliances switch on and off within a facility. Surge protective devices (SPDs), such as transient voltage surge suppressors (TVSS) and varistors, come into play when such circumstances arise.

These components are specifically designed to regulate and limit the voltage reaching the connected equipment, thereby safeguarding it from potential harm. The clamping voltage is essentially the maximum voltage level which the SPD will permit to pass through to the protected device; any voltage exceeding this threshold will be suppressed or diverted away from the equipment, ensuring its continued safe operation. The purpose of clamping voltage is to provide a clear point of reference in selecting appropriate surge protection solutions for specific applications.

By understanding the voltage tolerances of the delicate electronics in question, it is possible to choose an SPD that features a suitable clamping voltage rating, which in turn guarantees adequate protection without causing undue harm to the equipment. For instance, devices with low voltage tolerances may require a lower clamping voltage, while more robust equipment can handle higher clamping voltages. In practice, the clamping voltage must strike a careful balance: if set too low, the SPD may frequently engage and wear out prematurely, while if selected too high, it may not provide the necessary protection to the connected equipment.

By considering the clamping voltage along with other relevant specifications, users can ensure optimal protection for their electronic systems, prolonging their lifespans and maintaining their performance and reliability.

Examples of Clamping Voltage

Clamping voltage is a term used in electronics and electrical engineering to describe the maximum voltage limit that a device can tolerate without any damage. It is mainly used in reference to surge protectors or voltage clamping devices like Transient Voltage Suppressor (TVS) diodes, varistors, and gas discharge tubes. Here are three real-world examples of clamping voltage:

Surge protectors for home appliances: Surge protectors or power strips with built-in clamping voltages help safeguard sensitive electronic devices like computers, televisions, and gaming consoles from voltage surges or spikes. For instance, if there’s a lightning strike or a sudden power surge, the surge protector will clamp the voltage, ensuring it does not exceed its specified limit and thus protecting the connected devices from potential damage.

Automotive electronics protection: Modern cars include multiple electronic components and systems, such as engine management systems, advanced driver assistance systems (ADAS), and infotainment systems which are sensitive to voltage fluctuations. To protect these components, voltage clamping devices like TVS diodes, with specified clamping voltages, are used to absorb the sudden voltage spikes, ensuring that the devices and systems remain functional and unharmed.

Telecommunication and network infrastructure protection: Telecom and data centers rely on vast network infrastructures with various electronic components, including routers, switches, and servers, which can be highly sensitive to voltage surges and fluctuations. Voltage clamping devices, like gas-discharge tubes and varistors, with specifically designed clamping voltages, help to protect these equipment from damage caused by lightning strikes, power surges, or electromagnetic interference, maintaining network stability and continuity.

FAQ: Clamping Voltage

What is clamping voltage?

Clamping voltage, also known as let-through voltage or suppression voltage, is the maximum voltage level that a surge protection device (SPD) will allow to pass through itself to the protected equipment. It is a crucial parameter when evaluating the performance and effectiveness of an SPD since it determines the degree of protection it offers against voltage surges.

Why is clamping voltage important?

Clamping voltage is important because it signifies the threshold at which the surge protector diverts harmful voltage surges away from the connected equipment. A lower clamping voltage indicates better protection against voltage spikes, reducing the risk of damage to the connected devices.

How is clamping voltage determined?

Clamping voltage is determined by the design and materials of the surge protection device. The voltage level is usually specified in the product datasheet or technical documentation. In general, clamping voltage is measured during a standardized test, where a surge is applied to the SPD, and the let-through voltage is recorded.

What is an appropriate clamping voltage for my equipment?

The appropriate clamping voltage for your equipment depends on the specific requirements and sensitivity of the devices being protected. Equipment with lower voltage tolerances requires surge protectors with lower clamping voltages to ensure optimal protection. Always consult the manufacturer’s specifications for your equipment and choose a surge protector with a clamping voltage that meets or exceeds those requirements.

Can clamping voltage change over time?

Yes, the clamping voltage of an SPD can change over time due to factors such as temperature, age, and wear and tear. Frequent exposure to voltage surges, excessive current draw, or physical damage can degrade the components within the surge protector, leading to a higher clamping voltage. It’s essential to inspect and replace your surge protectors periodically to ensure optimal protection for your equipment.

Related Technology Terms

  • Transient Voltage Surge Suppressor (TVSS)
  • Metal Oxide Varistor (MOV)
  • Voltage Clamping Circuit
  • Surge Protection Device (SPD)
  • Peak Inverse Voltage (PIV)

Sources for More Information


About The Authors

The DevX Technology Glossary is reviewed by technology experts and writers from our community. Terms and definitions continue to go under updates to stay relevant and up-to-date. These experts help us maintain the almost 10,000+ technology terms on DevX. Our reviewers have a strong technical background in software development, engineering, and startup businesses. They are experts with real-world experience working in the tech industry and academia.

See our full expert review panel.

These experts include:


About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

More Technology Terms

Technology Glossary

Table of Contents