What is electrostatic discharge?
It is an unwanted electricity which is generated through tribocharging. Tribocharging is a type of contact electrification where certain materials become electrically charged after they are separated from a different material with which they were in contact. For example, lightning strike and in our childhood when we use to rub our hairs with the scale and than pick up the piece of paper through the scale.
How electrostatic discharge (ESD) effects electronics?
Static is simply the build up of charge between two surfaces. It arises when surfaces rub together and this results in an excess of electrons on one surface and a deficiency on the other.
The surface on which the charge accumulates will acts as capacitor. Unless there is a path for the charge to move through, the resulting voltage stays in place for a long period, giving rise to "static electricity."
When a conduction path exists, current flows through it and the charge reduces. The discharge has a time constant connected with it. With a high resistance, a lesser current will flow for a longer period of time. With a low resistance, the discharge will be significantly faster.
It can cause permanent damage to low power circuits and electro static sensitive devices.
There are multiple factors that decides the amount of voltage and current which are produced. The size of a person, the level of movement, the material against which the discharge is done, and the humidity of the air.
| Tribo-electric Material Series |
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The one at the top of the series will be receive positive charge, while the one at the bottom will be receive negative charge. |
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Positive charge Skin Hair Wool Silk Paper Cotton Wood Rubber Rayon Polyester Polythene Pvc Teflon Negative charge |
ANTI STATIC ESD WRIST STRAP
An anti-static device used to prevent electrostatic discharge (ESD) by safely grounding a person who is working on sensitive electronic components which could be damaged due to ESD, and component could get damaged due to ESD whether the person is working in a Factory or a small PCB. It is an adjustable wristband used by people in electronic factories or electronic engineers to protect electronic devices that can be damaged by ESD. It is manufactured with a conductive carbon interior coating for static control and protection.
The wrist strap first side which is worn on hand and the end of the strap
gets connected to the ground through a coiled cable as well as 1 mega
ohm resistor which is inside if the strap. The cable prevents the shock for
the electronic components. The coiled path itself work as a high resistor to protect the person wearing the strap.
FEATURES
- Adjustable wristband
- Coiled long cable comfortable while working.
- Made with Anti-allergic material.
STEPS TO USE ANTI STATIC ESD WRIST STRAP
- Choose a anti static ESD strap to ground yourself : There are 2 kinds of ESD straps – those that have a cord or wire you use to connect yourself to a ground, and other are wireless.
People working on the devices or the components should use a wired strap to get safe from the risks.
- Wear the anti static ESD strap around your wrist. The person working in manufacturing plants may first put on the strap before starting with the work, the ESD strap is easy wear as it is elastic. Make sure that the strap is in direct contact with your skin all the time.
- Attach the other end of the strap to a common ground. At the other end of the cord attached to your wrist strap is an alligator clip that you can use to connect yourself to a common ground. If the person is working at home he or she may not have a common ground point. In that case, hold the alligator clip to a metal part of the computer you're working on. Make sure the metal part that you clip your strap should be clean and unpainted. Painted surfaces are ineffective grounds.
- Wear the ESD strap whenever around the ESD-sensitive items. Any time the person is holding or working with computer components, such as motherboards or video cards, that are not installed in the computer case, keep yourself grounded. Otherwise, electrostatic discharge could damage those components. However, a single shock won't damage a component but it can cause poor performance. Multiple discharges can also have a bad effect.
USES
- Safely ground a person working on very sensitive electronic devices, to prevent the buildup of static electricity on their body.
- It also Protects the person working on the devices from shocks.
IMPORTANT POINTS
- Attach the wire on the same side of the equipment as the arm that is wearing the antistatic wrist strap. Due to this the wire will be out of the way while working.
- Although wearing a wrist strap will help to prevent static charge, further reduce the risks by not wearing clothing made of silk, polyester, or wool. These fabrics are more likely to generate a static charge.