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Electrostatic Discharge (ESD)

In this video from ITFreeTraining, I will look at electrostatic discharge. Electrostatic discharge occurs when a statically held charge moves to another object that has an unequal charge in order to balance the charge held between the two objects. This can damage electronic devices. This video will look at how you can prevent electrostatic discharge from damaging your equipment. Download PDF handout http://itfreetraining.com/handouts/ap... Electrostatic Discharge (ESD) 0:24 To start with, I will look at what electrostatic discharge or ESD is. Electrostatic discharge is simply a rush of static charge to another object. So, when an object with a lot of charge comes into contact with an object with no charge, the charge will attempt to equalize across the two objects. To understand this better, consider that you have a human. Humans don’t store or create static electricity that well. This is because humans are mostly made of water and our bodies don’t generate a lot of electricity. We only need a small amount of electricity to move our muscles and make are hearts beat etc. However, things like the clothes that we wear can create and store a lot of static electricity. Clothes made of synthetic materials are more prone to creating and storing static electricity. Material like cotton does not create or store as much static electricity as synthetic materials do. Also, if the humidity is low, this increases the amount of static electricity that can be created. For example, static electricity can be built up by the body quite easily by shuffling your feet across a carpet. If the humidity is low, the amount of static electricity that is built up is a lot higher. So, let’s consider what happens when your body builds up a static charge. Discharge 1:46 When your body builds up a static charge, the charge will follow the path of least resistance. The destination will be a body with unequal charge. So essentially the static electricity is attempting to balance the charge out with another body. One of the most common examples you will come across of static electricity is when you touch a door knob. If your body is charged up with static electricity, usually from walking or dragging your feet on the carpet, when you touch a door knob the static electricity will be transferred to the door knob and to ground. When this occurs, you will usually get a mild electric shock. To get around this, rather than touching the door knob, grab the door knob with your whole hand. This will increase the surface area of contact and thus increase the amount of surface area the static electricity can travel through. This will decrease the chance that you will get an electric shock. Touching a door knob while statically charged won’t cause any problems other than a minor electric shock. However, touching an electrical component can cause damage. Let’s have a look at how you can prevent this from happening. Work Area 2:56 To start with, let’s consider what a work area may look like when it is designed with anti-static protection. Keep in mind, this is just a simple example and there is a huge range of anti-static devices and furniture you can purchase. Everything from the floor, the chair, the desk and your cabinets can be designed with anti-static in mind. For the general IT technician, unless it is a specially designed area, you will probably have little anti-static prevention by design. The most common ESD equipment that you will come across is a workbench. An ESD workbench will need to be grounded to give somewhere for static electricity to go. This is done either by a power cable or ground cable. Using a power cable is the more common way of doing it. You will find that some devices and cabinets use the power cable to provide a ground. Static electricity needs to have somewhere to go, but it’s not always about providing a path of least resistance. Let’s have a look why. Anti-Static Mats 3:58 To help prevent electro static discharge from damaging electronics, one common method is to use anti-static mats. The mats may be stuck on a table or purchased as separate mats. It may surprise you but anti-static mats are made of high resistance material. Essentially this means that ESD will flow across the material at a very slow rate. I keep talking about having a path of least resistance, so why would you want something of high resistance material rather than providing a path of less resistance? References “The Official CompTIA A+ Core Study Guide (Exam 220-1001)” Chapter 3 position 2989-3528 “Picture of officer worker. Suit” https://openclipart.org/detail/293106... “Static electricity” https://en.wikipedia.org/wiki/Static_... “Picture of anti-static bags: Background removed” https://en.wikipedia.org/wiki/Antista... Credits Trainer: Austin Mason http://ITFreeTraining.com Voice Talent: HP Lewis http://hplewis.com Quality Assurance: Brett Batson http://www.pbb-proofreading.uk