What is Electrostatic Discharge (ESD)?
What is ESD and How Do We Protect Our Computers From it?
You might have heard or read that before you work on the internal components of the computer, like when you are performing an upgrade, you must observe the ESD precautions.
So what is this ESD? ESD is an acronym for Electrostatic Discharge. It is a rapid transfer of static charge between two objects with different potentials especially when they come into contact or close proximity.
For an ESD event to occur, it requires a build up of Electrostatic charge. This electrostatic charge is created when different materials rub together, one of the materials ending up being positively charged and the other negatively charged.
When this electrostatic charge comes into contact with the right material, it is transferred and an ESD event occurs. This charge is the one that destroys the electronic components because the intense heat generated can melt or vaporize the tiny parts of the component.
Symbol for Electrostatic Sensitive Protected Device
How Electrostatic Discharge is Created
Humans generate high levels of static charges in their bodies, a good evidence being the shock we experience when walking on a carpet and touching something metallic like a doorknob.
For humans, in order to feel a static shock, most people need at least about 3,000-4,000V on their body, while for an electronic component it may only take 100V, or even less, to cause a considerable damage. This level of voltage can be nearly continuously present on our bodies without us knowing it or feeling any effects.
If two objects that have different voltages (potential) approach each other closely enough to touch, or are placed in close proximity a charge may pass from one of the object to the other in a fast electrostatic discharge.
While this process only lasts a microsecond or less, the peak discharge current can be several Amps and the peak power can be in the kilowatt range! If subjected to ESD sensitive components like memory, processor, chip-sets etc, that high voltage destroys them. ESD is actually the major cause of semiconductor device failures in the electronic field.
This Symbol Denotes Devices is Susceptible to ESD Damage
What Causes ESD?
ESD can be caused by static electricity (build up of electric charge) which is often created when separation of electric charges occurs when two materials are brought into contact and then are separated (tribocharging).
This is usually because the friction between the two creates a difference of electrical potential that then leads to an ESD event.
The other cause of ESD is electrostatic induction, this happens when an electrically charged object is placed near a conductive object isolated from ground.
The charged object creates an electrostatic field that causes electrical charges on the surface of the other object to redistribute creating regions of excess positive and negative charges.
An ESD Rubber Mat Structure
What Damage Does ESD Cause in an Electronic Device?
We can categorize the damage from ESD into two:
Catastrophic damage – even the name here is suggesting the kind of damage we expect. This causes total failure of the electronic device immediately after the ESD encounter.
This will be as a result of a semiconductor junction or a connecting metallization having been damaged by the electrostatic discharge.
Latent damage – after an ESD attack, the component seems to be working fine only to fail sometimes in the future.
Antistatic Wrist Strap
How Do We Take Care of ESD?
There are a wide range of measures or ESD precautions that can be taken to protect your computer components from being affected by ESD. Here are some of the basic ones you can utilize.
- Make use of a grounded rubber mat: - ESD mats are designed to drain the Electrostatic charge from items placed on them.
They are divided into two categories:- ESD table top mats or ESD Work surface mats used to place the motherboard or any other component you are working on and floor mats placed on the floor of your workplace.
- Make use of anti static wrist strap: - The wrist strap is worn or tied on the wrist and the other end of the wire is hooked using crocodile clip to the chassis (unpainted parts of your system unit).
This is a sure way of grounding all the ESDs that will be generated by your body.
- 3.Spraying anti static solutions: - You can spray anti static solutions in your workshop to reduce static build up.
All the above methods you have to make use of some money, but the others mentioned here, you don't have to spend even a single cent.
- Before working on the internal components of your computer, start by touching the grounded metal casing.
- Hold ESD sensitive devices by edges.
- Do not remove ESD sensitive devices from their anti static bags unless you are ready to use them. This should also apply when you are storing or transporting them.
ESD poses a serious threat to electronic components especially the motherboard components. So, it is vital for a computer technician or anyone working with the ESD sensitive components to make sure that he or she observes the ESD precautions.