1. Course ILT Electricity and power systems Unit objectives Measure and describe the characteristics of electricity Identify static electricity and follow ESD safe practices when working with computers Describe the purpose and features of power supplies and install a new power supply into a PC Troubleshoot faulty power supplies

2. Course ILT Topic A Topic A: Electricity and electronics Topic B: Static electricity Topic C: Power supplies Topic D: Power supply troubleshooting

3. Course ILT Electricity characteristics Voltage Current Alternating or direct current Resistance and impedance Power and energy

4. Course ILT Activity A-1 Examining the characteristics of electricity

5. Course ILT Electrical safety Current can kill The 1–10–100 rule Calculating current V = i * r Resistance of the human body

6. Course ILT Safety precautions Don’t touch exposed contacts Touch only insulated handles of tools Leave covers on equipment Work one-handed Don’t stick things into electrical sockets Remove jewelry, watches, etc. Keep hands clean and dry Don’t work in wet surroundings

7. Course ILT Activity A-2 Considering electrical safety

8. Course ILT Digital multimeter

9. Course ILT Analog multimeter

10. Course ILT Using a multimeter Measuring resistance Measuring voltage Measuring current Measuring continuity

11. Course ILT Activity A-3 Measuring electrical values

12. Course ILT Topic B Topic A: Electricity and electronics Topic B: Static electricity Topic C: Power supplies Topic D: Power supply troubleshooting

13. Course ILT Static electricity Build up of charges Static dangers Discharge voltages –3,000+ volts to feel –8,000+ volts to see spark –35,000 volts on a dry day on carpet –1,000 volts can damage electronics

14. Course ILT Prevent static build-up Don’t shuffle your feet Increase the humidity Keep yourself grounded Wear cotton, not synthetics Remove carpeting Use air ionization system

15. Course ILT Prevent static discharge Equalize charge differences safely –Unplug the equipment –Touch its metal chassis or power supply Keep yourself and equipment connected –Wrist straps and anti-static mats –Static-safe bags

16. Course ILT Static wrist strap

17. Course ILT Typical internal components Power supply CD-ROM drive Hard drive CPU / fan Motherboard Adapter card

18. Course ILT Slide catches Slide catch, move to open side of case

19. Course ILT Determining which side to open Ports and connectors attached to motherboard Open this side to access components

20. Course ILT Removable front cover Alignment posts Alignment holes Spring catches

21. Course ILT Activity B-1 Opening the computer case while following proper ESD precautions

22. Course ILT Topic C Topic A: Electricity and electronics Topic B: Static electricity Topic C: Power supplies Topic D: Power supply troubleshooting

23. Course ILT A PC power supply

24. Course ILT Voltage selection switch

25. Course ILT Typical power requirements Motherboard30 W Memory10 W / 128 MB CPU65 W or more Hard drive5 – 15 W CD-ROM drive10 – 20 W Floppy drive5 – 10 W Adapter card5 – 30 W

26. Course ILT Standard outputs +3.3 V14 AAGP video cards, motherboard -5 V0.3 AISA bus adapter cards +5 V30 AMotherboard, CD/DVD drives, hard drives, PCI adapter cards, Pentium III and earlier processors +5 V0.85 A“Soft power” switch -12 V1 AOlder network adapters and serial ports +12 V12 ACD/DVD drives, hard drives, Pentium 4 and Athlon processors, motherboard

27. Course ILT Power_Good signal Signals CPU that power is stable and sufficient +5 V over specific wire Must arrive at correct time

28. Course ILT Peripheral power connector “Molex” connector

29. Course ILT Floppy power connector “Berg” connector

30. Course ILT SATA power connector New, for Serial ATA drives

31. Course ILT Wire colors Yellow = +12 V Red = +5 V Black = ground

32. Course ILT Motherboard power connectors

33. Course ILT Power supply form factors ATX/NLX150 x 140 x 86 millimeters 486 and Pentium PCs First with soft- power switch and 3.3V SFX100 x 125 x 63.5 millimeters Pentium PCsNo -5 V output for ISA cards WTX150 x 230 x 86 (single fan) 224 x 230 x 86 (double fan) Pentium PCsNo -5 V output for ISA cards

34. Course ILT Activity C-1 Examining a power supply and connectors

35. Course ILT Topic D Topic A: Electricity and electronics Topic B: Static electricity Topic C: Power supplies Topic D: Power supply troubleshooting

36. Course ILT Troubleshooting symptoms Computer fails to boot when powered on, but boots after pressing Ctrl + Alt + Delete Computer intermittently stops working or reboots You don’t have sufficient power connectors to connect all the devices you want to install Computer fails to boot at all, with no lights or beeps; fans don’t start Computer fails to boot, but fans start

37. Course ILT Activity D-1 Troubleshooting power supply problems

38. Course ILT Unit summary Measured and described the characteristics of electricity Identified static electricity and followed ESD safe practices when working with computers Described the purpose and featurse of power supplies; and installed a new power supply into a PC Resolved faulty power supply problems