STAT-X DEUTSCHLAND · COMPETENCE CENTRE
Understanding electrostatics. Recognising the connections.
From electric charge to shielding: background knowledge for practical ESD protection.
Electrostatics deals with stationary electric charges and their effects. Its principles explain why materials become charged, electric fields arise and suitable protective measures are necessary.
Four concepts worth distinguishing
Electric charge
A physical property that can be positive or negative. Like charges repel, opposite charges attract. The unit is the coulomb.
Potential and voltage
Electric potential describes the potential energy per unit charge relative to a reference point. Voltage is a potential difference between two points; its unit is the volt.
Electric field
An electric field describes the force acting on electric charges. It can act without direct contact with a charged object.
Resistance and dissipation
Electrical resistance affects current flow. Whether and how quickly charge can dissipate also depends on the overall arrangement – including capacitance and contact connections.
What explains common observations?
Contact and separation: where does charging come from?
When materials come into contact and are subsequently separated, charge can be transferred. Friction often repeats and intensifies these contacts. These effects therefore occur, for example, when unwinding film or walking.
The amount of charging depends on factors including the combination of materials, surface condition and environmental conditions.
Electrostatic induction: an effect without contact
An external electric field can displace mobile charges in a conductor. This creates regions with different charge distributions without the conductor touching the object causing the field.
When connections are made or broken, this can create a critical discharge situation. This is one reason to consider nearby insulating materials in ESD protection.
Discharge: why a spark is not necessary
During an electrostatic discharge, charge is transferred between objects at different potentials. Not every discharge produces a spark visible to people or a perceptible effect.
The sensitivity of electronic components therefore cannot be assessed using human perception.
Shielding: what does a conductive enclosure do?
Conductive enclosures can shield electric fields. The Faraday cage is a familiar example. How well an actual arrangement protects depends on its construction and the effect being considered.
For ESD protective packaging, the applicable properties and tests must also be considered. A metallic-looking surface alone does not demonstrate suitability.
Grounding and equipotential bonding: what is the difference?
Grounding establishes a connection to earth. Equipotential bonding connects conductive parts so that hazardous or unwanted potential differences are limited.
In ESD protection, these connections must suit the system and be compatible with electrical safety. An insulator cannot be discharged like a conductor simply by attaching a cable.
From early observations to technical applications
Amber and early observations
Long before modern electrical engineering, people observed that rubbed amber could attract light objects. The root of the word “electricity” comes from the Greek word for amber.
Systematic experiments
William Gilbert systematically investigated electrical and magnetic phenomena. Later, Benjamin Franklin’s work, among others, contributed to the understanding of electric charge.
Describing forces quantitatively
Charles Augustin de Coulomb investigated the forces between electric charges. The law named after him describes how these depend on charge and distance.
Understanding fields and shielding
Michael Faraday’s work shaped the understanding of electrical and magnetic phenomena. His experiments with conductors and charge distribution illustrate important principles of electrostatics.
What does this mean for your ESD protection?
The physics stays the same – the application determines the measures.
A grounded conductor, a charged insulator and a sensitive component behave differently. Effective protective measures must therefore consider both the properties of the materials and the operational process.
In electronics manufacturing, the focus is on protecting sensitive components. In areas with potentially explosive atmospheres, the applicable additional requirements must be observed; an ESD protection concept for electronics does not automatically cover this task.
Apply the principles to your process
The “Understanding ESD” page connects these concepts with typical risks and protective measures in the electronics industry.
Sources and further reading
- Historical background: History of electrostatics – VDE.
- Basics with images and animations: Electric charges explained visually – LEIFIphysik.
- Shielding in an experiment: Faraday cage – University of Konstanz video on HubbS.
- For operational use: Stat-X ESD standards overview.