How does static electricity arise?

Static electricity is a natural physical phenomenon that accompanies us every day. In everyday life we notice it as a small spark when touching metal, but in electronics manufacturing it can damage components worth thousands of euros. Understanding how it arises is the basis of effective ESD protection.

What is static electricity?

Static electricity is electric charge accumulated on a material surface. When two materials touch and separate, electrons move between them – one gains a surplus, the other a deficit. A potential of several thousand volts builds up; on contact with an object at a different potential, an electrostatic discharge (ESD) occurs.

The triboelectric effect

The most common cause is the triboelectric effect – the exchange of electrons when materials touch and separate: walking across the floor, clothing friction, handling plastic bags, moving containers, unrolling adhesive tape, or shifting components in packaging. Plastics are therefore among the biggest sources of problems.

How much voltage can build up?

The values are surprisingly high: walking across carpet up to 35,000 V, handling plastic up to 7,000 V, getting up from a chair up to 18,000 V. People only feel discharges from about 3,000 V – yet modern components are damaged far below that.

The influence of humidity

Humidity plays a decisive role. At low humidity (10–20%) the highest charges occur; at higher humidity (60–90%) they are much lower. Dry heated air in winter noticeably increases the ESD risk.

How to reduce charge build-up

Dissipative ESD flooring, ESD table mats, controlled humidity and ionisers for insulating materials that cannot be grounded all help. The framework is an EPA workstation.

Conclusion

Static electricity inevitably arises wherever materials touch and separate. The article how an electrostatic discharge works shows how the resulting discharge damages components. Find more guides in the ESD Guide.