Electrical Safety Precautions

Here are the study notes in markdown format:

Potentials Dangers of Electrical Shock and Burns

• Power cord is frayed or damaged
• Water or other liquid is spilled near electronic devices
• Device has been dropped or physically damaged
• Strong electronics odor is present
• Power supply or fans make a whining noise
• Smoke is observed or case feels unusually warm

Protecting Yourself Against Electrical Shock and Burns

• Ground yourself with an anti-static grounding bracelet when working on sensitive low-voltage equipment
• Do not ground yourself when working with power supplies, printers, and CRT monitors that contain capacitors
• Never use water to put out a fire (water is a conductor)
• Use a fire extinguisher rated to put out electrical fires
• Fire extinguisher ratings: Class A (wood, paper, or other combustibles), Class B (liquids), Class C (electrical)

Protecting Equipment Against Static Electricity or ESD

• Electrostatic discharge (ESD) occurs when two objects with dissimilar electrical charges touch
• ESD can cause two types of damage: catastrophic failure (destroys the component) and upset failure (damages the component so it does not work well)
• Protect against ESD by grounding yourself with:
  • Ground bracelet (ESD strap, anti-static wrist strap, or ESD bracelet)
  • Ground mats (ESD mats)
  • Static shielding bags (anti-static bags)
  • Anti-static gloves (ESD gloves)

Rules for Protecting Equipment Against ESD

• Rule 1: Ground yourself and touch the other person before passing a circuit board or other component
• Rule 2: Leave components inside anti-static bags until ready to use them
• Rule 3: Work on hard floors, not carpet
• Rule 4: Don't work on a computer in a cold and dry atmosphere
• Rule 5: Remove packing tape and cellophane from around work area (materials that attract ESD)
• Rule 6: Keep components away from hair and clothing

Tools Used by a PC Repair Technician

• Essential tools:
  • Ground bracelet, ground mat, anti-static gloves
  • Flat-head screwdriver
  • Phillips-head or cross-head screwdriver
  • Torx screwdriver set (size T15)
  • Insulated tweezers
  • Extractor
  • OS recovery CD or DVD
• Many other non-essential tools exist
• Use a toolbox

What's Inside a Computer Case

• Computer case: holds power supply, motherboard, processor, memory modules, expansion cards, hard drive, optical drive, and other drives
• Motherboard: largest and most important circuit board
• Processor (CPU): processes most of the data and instructions for the entire system
• Expansion cards (adapter cards): provide more ports than those provided by the motherboard
• Memory modules (RAM): temporary storage for data and instructions as they are being processed by the CPU
• Hard drives and other drives: permanent storage used to hold data and programs

Form Factors Used by Computer Cases, Power Supplies, and Motherboards

• Form factors: standards that describe the size, shape, screw hole positions, and major features of computer cases, power supplies, and motherboards
• Two form factors used by most desktop and tower computer cases and power supplies: ATX and Mini-ATX

Drives, Their Cables, and Connectors

• Hard drives: two standards - Serial ATA (SATA) and Parallel ATA (PATA)
• Floppy drive: uses a 34-pin twisted cable
• Other drives: optical drive, tape drive

Protecting Yourself and Equipment Against Electrical Dangers

• Important to understand electricity and how to protect yourself and equipment against it
• Must learn to prevent getting shocked or damaging a component

Measures and Properties of Electricity

• Alternating current (AC): oscillates between negative and positive voltage
• Direct current (DC): travels in one direction
• Rectifier: a device that converts AC to DC
• Inverter: a device that converts DC to AC
• Transformer: devices that changes the ratio of voltage to current

Tools and Safety Precautions

• Power supply tester: measures output of each power supply connector
• Multimeter: measures several characteristics of electricity in a variety of devices
• Loopback plug: used to test a port in a computer or other device to make sure the port is working
• Cleaning solutions and pads: use with care and follow Material Safety Data Sheet (MSDS) instructions
• Managing cables: keep cables in a safe place and use cable or cord covers if necessary
• Lifting heavy objects: follow guidelines to avoid back injury

Learn about potential dangers and take necessary precautions to protect yourself from electrical shock and burns when working with low-voltage equipment.