Electrostatic discharge (correctly: discharge of static electricity): Charge balancing process between solid, liquid or gaseous media with different electrostatic charge. Usually accompanied by surface, corona, spark or even lightning discharge, can, however, also only be conducted via a contact point, i.e. if the potential difference does not exceed 330 V before contact.
In the case of sparking, flammable gases and vapours or explosive mixtures may be ignited and electronic components may be damaged or destroyed or the functionality of electronic equipment may be impaired through the currents and fields resulting from electrostatic discharge. The first effects fall within the scope of fire and explosion protection and technical safety, whereas the last effects fall within the scope of protection of electrostatic-sensitive devices (
ESDS) and electromagnetic compatibility [
EMC].
Possible human body discharge from persons to circuits, printed circuit boards, operating elements, and receptacle surfaces during transport, assembly, testing, operation, repair, and service operations are of particular importance when using electronic equipment.
The following electrical values are to be expected:
- Energy content 10 to 30 mJ
- Electrostatic voltage 0.1 to 20 kV
- Discharge current up to 30 A pulse amplitude
- Rate of current change up to 100 A/ns
- Electric field strength 1 to 4 kV/m
- Magnetic field strength up to 15 A/m in cm nearness to discharge
