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Which resistance values are considered conductive, dissipative, or insulating?
Why testing ESD materials is so important
ESD materials play a central role in protecting sensitive electronic components from electrostatic discharges (ESD)Even voltages that are neither visible nor perceptible to humans can permanently damage electronic components or significantly shorten their lifespan. Furthermore, such damage often leads to quality problems, failures, or even costly warranty claims.
For this reason, special [materials] are particularly used in electronics, automotive, semiconductor and battery manufacturing. ESD materials for use. These include, among other things, plastic housings, packaging, work mats, coatings and floor coverings. They are intended not only to reduce the generation of electrostatic charges, but also to dissipate them in a controlled manner and thus effectively protect sensitive components.
To ensure these materials can reliably and permanently fulfill their protective function, their electrical properties must be regularly checked. This is the only way to guarantee that the required ESD properties are maintained even under real-world operating conditions. The most important parameter for evaluating an ESD material is its electrical resistance, as it largely determines how quickly and to what extent electrical charges can be dissipated.
How do you test ESD materials for resistivity and dissipative properties?
Testing ESD materials is an important part of quality assurance in the electronics, automotive, semiconductor, and plastics industries. The aim is to ensure that materials dissipate or isolate electrostatic charges in a controlled manner, thereby preventing damage to sensitive components.
Even a single uncontrolled electrostatic discharge (ESD) can permanently damage electronic components or significantly shorten their lifespan. Therefore, ESD floor coverings, ESD packaging, ESD workstations, plastics, and coatings are regularly tested for their electrical properties.
Measuring surface resistance and volume resistance determines whether a material is conductive, dissipative, or insulating. The measurement results serve as a basis for selecting suitable materials, monitoring production processes, and ensuring compliance with quality standards.
Regular testing of ESD materials thus helps to avoid electrostatic discharges, increase product safety and ensure the long-term quality of electronic assemblies and systems.
What are ESD materials?
ESD materials are special materials designed to either dissipate electrostatic charges or reduce their generation in the first place. Depending on the application and specific requirements, materials with different electrical resistance ranges are used. While some applications require the fastest possible dissipation, others prefer a controlled and uniform discharge.
A conductive material typically dissipates electrical charges very quickly. With ESD materials, however, this process is deliberately controlled and significantly slower. This prevents sudden and potentially damaging electrostatic discharges that could impair or even destroy sensitive electronic components.
To reliably assess the electrical properties of a material, classification is usually based on the surface resistance or volume resistance. Both parameters provide important information about how electrical charges behave on or within a material and whether the material is suitable for the intended ESD application.
Conductive, dissipative or insulating – what is the difference?
The classification is based on the measured resistance value.
Conductive materials
Conductive materials have a very low electrical resistance. This allows electrical charges to be dissipated almost instantly. The typical resistance range is below 10⁵ Ω. Examples of conductive materials include metals, conductive carbon coatings, and special conductive plastics.
Conductive materials
Conductive materials constitute the classic ESD range. They prevent uncontrolled electrostatic discharge and simultaneously ensure the safe and controlled dissipation of charges. The typical resistance range is between 10⁵ Ω and 10¹¹ Ω. This class of materials includes, among others, ESD plastics, ESD packaging, ESD work mats, and ESD floor coverings.
Insulating materials
Insulating materials, or insulators, almost completely prevent the flow of electricity. This allows electrostatic charges to build up and be stored for extended periods. The typical resistance range is above 10¹¹ Ω. Typical examples include standard plastics, glass, ceramics, and numerous paints and coatings.
Classification of materials based on their electrical resistance
Materials are classified as conductive, dissipative, and insulating based on their electrical resistance.
| Klassifizierung | Typical resistance range | Features | Typical examples |
| Conductive | < 10⁵ Ω | Electrical charges are dissipated very quickly and almost without delay. | Metals, conductive carbon coatings, special conductive plastics |
| Dissipative (ESD) | 10⁵ Ω to 10¹¹ Ω | Charges are controlled and safely dissipated. This prevents dangerous electrostatic discharges. | ESD plastics, ESD packaging, ESD work mats, ESD floor coverings |
| Insulating | > 10¹¹ Ω | The flow of electricity is largely prevented. Electrostatic charges can build up and be stored for extended periods. | Standard plastics, glass, ceramics, many paints and coatings |
In practice, conductive materials are particularly well-suited for ESD applications. They offer an optimal compromise between the safe dissipation of electrostatic charges and the protection of sensitive electronic components. Whether a material is classified as conductive, dissipative, or insulating can be reliably determined by measuring its surface or volume resistance. Therefore, precise resistance measurements are an important part of quality assurance in the electronics, automotive, plastics, and semiconductor industries.
Measure surface resistance or volume resistance?
Which measurement parameter is relevant for evaluating a material depends primarily on the specific application and the required material properties. While in some cases the behavior of electrical charges on the material surface is the focus, in other applications the resistivity within the material is crucial. For a meaningful evaluation, it is therefore important to understand the differences between surface and internal resistivity. Volume resistance to know.
Surface resistance
The Surface resistance This describes the ability of a material to conduct or dissipate electrical charges along its surface. This parameter plays a particularly important role in ESD applications, as electrostatic charges often initially build up on the surface of a material.
Measuring surface resistance is therefore particularly relevant for:
- ESD workstations
- Packaging
- Floor coverings
- Coatings
This measurement can be used to assess whether a surface can dissipate electrostatic charges quickly and in a controlled manner to effectively protect sensitive electronic components.
Volume resistance
In contrast, volume resistance describes the electrical resistivity through the material. It indicates how strongly a material opposes the flow of current within its volume and is therefore an important parameter for material characterization.
The volume resistance is particularly frequently determined for the following materials:
- Plastics
- Composites
- Films
- insulation materials
Especially in the case of engineering plastics, insulating materials or electrically modified compounds, the volume resistance provides important information about the electrical properties and the suitability for certain applications.
For a comprehensive and reliable material characterization, both surface resistance and volume resistance are often measured. Only the combination of both measurements allows for a complete evaluation of a material's electrical behavior.
Which standards are relevant for measuring surface and volume resistivity?
When measuring surface resistance, volume resistance and specific resistance Globally recognized standards are used. These ensure that measurement results are comparable, reproducible, and can be evaluated independently of the respective testing laboratory.
The most important standards for resistance and ESD measurement include:
- IEC 61340 2 3 – Test method for determining resistance and specific resistance for ESD applications
- ASTM D257 – Standard test method for determining the surface resistance and volume resistance of insulating materials
- JIS K6911 – Japanese standard for measuring the surface and volume resistivity of plastics and other insulating materials
These standards describe, among other things, the required test conditions, the electrode geometry, the applied measuring voltage, and the measurement procedure. This ensures that measurement results for surface resistance, volume resistance, and specific resistance can be determined as uniformly as possible.
For standard-compliant measurements, special [equipment/tools] are often used. Resistance and resistivity measuring devices Systems such as the Hiresta-UX and Loresta GX II support measurements according to the procedures described in ASTM D257 and JIS K6911 and are also suitable for numerous applications within the IEC 61340 series of standards. However, the specific conformity of a measurement to the standard always depends on the measurement setup used, the electrodes employed, and the defined test conditions.
Compliance with recognized standards plays a crucial role, particularly in the electronics, automotive, plastics, battery, and semiconductor industries. Standardized measurement methods form the basis for reliable quality assurance, adherence to customer specifications, and the objective evaluation of the electrical properties of materials.
In practice, surface resistance and volume resistance are often determined using measuring systems such as Hiresta-UX, Loresta GX II or Loresta-FX, depending on the resistance range and the type of material.
Why are precise measuring instruments crucial?
Even minor environmental influences can affect measurement results, especially with high-resistance materials. Humidity, contamination, or unsuitable electrodes frequently lead to measurement deviations.
Professional resistance measuring devices enable standard-compliant testing and deliver reproducible results even in the high resistance range.
Different measuring instruments are used depending on the resistance range. Devices such as the Hiresta-UX are frequently used to determine surface and volume resistances of insulators. Low-resistance and conductive materials, on the other hand, can be precisely characterized with devices such as the Loresta-GX II or Loresta-AX.
Selecting the right measuring instrument for surface, volume and powder resistance measurements
| Measurement task | Typical resistance range | Typical materials | Suitable measuring instruments |
| Measurement of insulators and highly insulating materials | 103 - 1014 Ω | Plastics, films, ceramics, coatings, insulation materials | Hiresta UX |
| Measurement of the surface resistance of ESD materials | 103 - 1014 Ω | ESD plastics, ESD packaging, ESD work mats, floor coverings | Hiresta UX |
| Measurement of volume resistance | 103 - 1014 Ω | Plastics, composite materials, insulation materials | Hiresta UX |
| Measurement of conductive and semiconducting materials | 10-4 - 107 Ω | Carbon compounds, conductive plastics, coatings, films | Loresta GX II |
| Low-resistance measurements and material development | 10⁻² to 10⁶ Ω | Metals, carbon materials, conductive polymers | Loresta FX |
| Research and development of batteries and functional materials | depending on material and application | Electrode materials, separators, conductive layers | Loresta GX II, Loresta FX |
| Powder characterization | specific powder resistance | Battery powder, graphite, carbon black, cathode and anode materials | PD 600 |
The selection of the appropriate measuring instrument depends not only on the expected resistance range, but also on the type of material, the sample geometry, and the requirements of the relevant standard. While highly insulating materials are typically tested with the Hiresta-UX, instruments such as the Loresta-GX II or the Loresta-AX are particularly suitable for conductive and semiconducting materials. For the characterization of powders, for example in the battery, chemical, or materials industries, the PD-600 powder measurement system was developed. Selecting the appropriate measuring system not only allows for more precise measurement results, but also reduces measurement times and improves the comparability of the results.
Key facts at a glance
The classification of materials into conductive, dissipative, and insulating forms the basis of every ESD assessment. Only precise resistance measurements can ensure that materials provide the required level of protection and comply with the requirements of relevant standards.
Especially in the electronics, automotive and plastics industries, standardized measurement methods are indispensable to ensure product quality, process reliability and ESD protection in the long term.
Frequently asked questions about material classification and resistance measurement
A material is considered conductive if its electrical resistance is very low and electrical charges can be dissipated quickly. Typically, materials with a resistance below 10⁵ Ω are classified as conductive. These include, for example, metals, conductive coatings, and special conductive plastics.
Conductive materials allow for the controlled dissipation of electrostatic charges, thereby preventing harmful electrostatic discharges. They typically have a resistance between 10⁵ Ω and 10¹¹ Ω and are frequently used for ESD packaging, work mats, floor coverings, and engineering plastics.
Surface resistance describes the current flow along the material surface, while volume resistance assesses the current flow through the material itself. Special electrodes and resistance measuring devices are used for both measurements, employing defined measuring voltages and test procedures.
Key standards include IEC 61340-2-3, ASTM D257, and JIS K6911. These standards describe test methods for determining surface resistance, volume resistance, and resistivity, as well as the required test conditions.
The measurement results are influenced by factors including temperature, humidity, material properties, measuring voltage, electrode geometry, and the chosen measurement setup. Therefore, resistance measurements should be performed under defined and reproducible conditions whenever possible.
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