A question that comes up, again and again, is “Are ElectroStatic charges and ElectroStatic discharges different?” so we thought it’d be helpful for everyone to put together a blog post on the subject. So, let’s get started:
ElectroStatic charges and ElectroStatic discharges are different. All material can tribocharge (generate ElectroStatic charges). This is static electricity which is an electrical charge at rest. When an electrical charge is not at rest but discharges (i.e. ESD), problems can occur. All matter is constructed from atoms which have negatively charged electrons circling the atom’s nucleus which includes positively charged protons. The atom having an equal number of electrons and protons balances out having no charge.
Electrostatic charges are most commonly created by contact and separation; when two surfaces contact then separate, some atom electrons move from one surface to the other, causing an imbalance. One surface has a positive charge, and one surface has a negative charge.
The simple separation of two surfaces, as when tape is pulled off a roll, can cause the transfer of electrons between surfaces, generating an ElectroStatic charge.
The amount of static electricity generated varies and is affected by materials, friction, area of contact and the relative humidity of the environment. At lower relative humidity, charge generation will increase as the environment is drier. Common plastics generally create the greatest static charges.
Many common activities may generate charges on a person’s body that are potentially harmful to electronic components.
If two items are at the same electrostatic charge or at equipotential, no discharge will occur. However, if two items are at different levels of ElectroStatic charge, they will want to come into balance. If they are in close enough proximity, there can be a rapid, spontaneous transfer of electrostatic charge. This is called discharge, or ElectroStatic Discharge (ESD).
Examples in daily life:
Electrostatic Discharge in Daily Life
In a normal environment like your home, there are innumerable ESD events occurring, most of which you do not see or feel. It takes a discharge of about 2,000 volts for a person to feel the “zap”. It requires a much larger ESD event to arc and be seen. While a discharge may be a nuisance in the home, ESD is the hidden enemy in a high-tech manufacturing environment. Modern electronic circuitry can be literally burned or melted from these miniature lightning bolts. Even less than 100 volts might damage a sensitive Class 0A component! ESD control is necessary to reduce and limit these ESD events. For more information on the damages ESD can cause, check out this post. For tips on how you can fight ESD in your production area, you should read this post.