What is electrostatic discharge (ESD)?

Electrostatic discharge or ESD is a spark or discharge resulting from a large potential difference in an electrically insulating material that causes a high and very brief electric current pulse. Power supplies have to comply with the minimum ESD requirements specified in EN 61000-6-2.

The electrostatic charge of objects results from the static electricity in different materials. A discharge can damage delicate electronic components. Electronic devices can be put at risk, for example, if someone wearing well-insulated shoes walks across a well-insulated floor covering. Therefore, in the production process for electronic components, comprehensive measures have to be taken to prevent ESD charges.

The minimum ESD requirements for devices are specified in EN 61000-6-2. The test conditions are described in EN 61000-4-2.

The following two test methods are used:

• Contact discharge:
  ESD voltage is discharged using high-voltage relays and a probe placed directly on a metal surface (the device housing).
• Air discharge:
  A probe charged with the ESD voltage is moved close to the test device until there is a sparkover. The air discharge method is used for non-conductive surfaces (for example, plastic housings or metal housings with an insulation film) and for electrical contacts.

The test device must be in operation during the ESD test.