Page 135 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

LESSON 73 - 76 : PCB Rework introduction to static

charger

Objectives
At the end of this lesson you shall be able to:
• explain various types of PCB and various tests carried out on PCB’s
PCB Rework introduction to static charger

Static electricity is primarily caused by the movement of electrons from one surface to another. When two materials
come into contact and then separate, some electrons may be transferred from one material to the other, leaving
one material with a positive charge (having lost electrons) and the other with a negative charge (having gained
electrons). This charge imbalance creates static electricity.
Types of Static Charges

Positive Charge (+): When an object loses electrons, it becomes positively charged because it has an excess
of protons.
Negative Charge (-): When an object gains electrons, it becomes negatively charged because it has an excess
of electrons.
Properties and Effects
Attraction and Repulsion: Objects with opposite charges attract each other, while objects with like charges
repel each other. This phenomenon can be demonstrated with simple experiments using objects like balloons,
plastic rods, and paper bits.
Electrostatic Discharge: When the charge on an object becomes large enough, it can discharge suddenly,
resulting in a spark. This discharge can be seen, for example, when you touch a metal doorknob after walking
across a carpeted floor.
Triboelectric Effect: The triboelectric effect is the phenomenon where certain materials become electrically
charged after they come into contact and then separate due to the exchange of electrons. This is the principle
behind rubbing a balloon on your hair to create static electricity.
Practical Applications
Photocopiers and Laser Printers: Static electricity is used in photocopiers and laser printers to transfer toner
(ink powder) to paper.
Air Purification: Some air purifiers use static electricity to remove particles from the air by attracting them to
charged plates.
Electrostatic Precipitators: These devices use static electricity to remove pollutants like dust and smoke
particles from industrial exhaust gases.

Safety Considerations
While static electricity is generally harmless in small amounts, it can cause damage in certain situations, such as in
electronics manufacturing environments where static discharge can damage sensitive components. Precautions
such as grounding and using anti-static materials are essential in such cases.
Prevention, Handling Of Static-Sensitive Devices Various:
Prevention and proper handling of static-sensitive devices are crucial in industries where electronic components
are manufactured, handled, or repaired. These devices can be damaged by electrostatic discharge (ESD), leading
to malfunctions or failure. Various standards and guidelines have been developed to ensure the protection of
static-sensitive devices. Here are some key aspects to consider:

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