EET 110 - Survey of Electronics

1. EET 110 - Survey of Electronics Chapter 25 - Appliance Cords & Connections Chapter 26 - Lighting Equipment

2. Types of electrical Cords • SPT parallel Lamp cord • thermoplastic - lamps, etc • HPN parallel Lamp cord • thermosetting - heaters, etc • SVT vacuum cleaner cord • thermoset or thermoplastic w/ thermoplastic outer shell

3. HPD heater cord • twisted thermoset, asbestos fill, and cotton or rayon braid cover • JS junior hard service • twisted thermoset, cotton fill, rubber jacket

4. Cord Connectors • Two prong plug cap • three wire plug cap • note black to brass term, white to silvered, green(bare) to green (ground) • cords • three wire extension cord • appliance plug • heating element appliances

5. Grounding Appliances • Range and dryer receptacles • remember that ground wire is for protection • Grounded appliances must be connected to the protective ground circuit. • Bonded to metal cases • Double-insulated appliances • an extra layer of insulating material

6. Ground Fault Circuit Interrupter • GFCI • detects current flow through ground connection • compares hot current to neutral current • breaks circuit if not equal • Test button • tested once per month

7. note GFCI does not include circuit breaker protection • GFCI breaker may be used to protect an entire circuit

8. Weatherproof fixtures • water resistant boxes, with covers for outlets, receptacles and lamps are available • metal or PVC • Caps on outlets • rubber gaskets for plates and lamp holders

9. Chapter 26 - Lighting Equipment • Incandescent lamps • tungsten filament • gives off light when hot • waste energy as heat • Rated in Watts (volts) • Lamp Bases • see figure 26-4

10. Trilight lamp • high, med, low settings • 40W and 60 W filaments - combined to give 100W • Replacing lamp socket • lamp fixture • Installing a light fixture • ceramic

11. Lamp types • recessed fixtures • track lighting

12. Fluorescent lighting • heat mercury in neon or other inert gas to ionize • inner coating (phosphorus) gives off light when exposed to UV • Ballast • provides starting voltage, • then limits current to hot tube

13. Preheat Fluorescent Light circuit • push button to head gas first to ionizing temp • then voltage is applied • high due to collapsing magnetic field • double pins • Glow-switch starter • bimetallic strip provides contact/break

14. Rapid start • ballast quickly heats the mercury • 1-2 second response • Instant Start • single pin at each end. • Ballast provides voltage start

15. Compact fluorescent bulbs • energy efficient lighting • High-Intensity Discharge lamps • halogen lamp is an example

16. Security Lighting • photoelectric control unit • CdS cell to monitor and turn on the light fixture • Light timers • Motion Sensors • Remote control lighting systems • X10 - home control units.

17. Chapter 30 – Capacitors & Inductors • Inductors – coils of wire • Stores current in magnetic field • Measured in Henrey’s • L • Opposes changes in current flow • Mutual and Self inductance

18. Inductive Reactance • Equivalent to Resistance • XL = 2fL – Measured in Ohms • Example 30-4 if 200mH inductor is operated at 1000Hz, what is the Inductive Reactance • XL = 2 fL = 2 x 3.14159 x 1000 x 200 x 10-3 = 1256 • LT series = L1 + L2 + L3 +… • LT (parallel) = L1 x L2/(L1 + L2)

19. Capacitance • Voltage is stored in electro-static field • Plates separated by electrolyte • RC time constant • t = RC • Capacitive Reactance • XC = 1/(2fC) • Measured in Ohms