EET 110 - Survey of Electronics

Chapter 25 - Appliance Cords & Connections

Chapter 26 - Lighting Equipment

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

• HPD heater cord– twisted thermoset, asbestos fill, and cotton or

rayon braid cover

• JS junior hard service– twisted thermoset, cotton fill, rubber jacket

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

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

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

• note GFCI does not include circuit breaker protection

• GFCI breaker may be used to protect an entire circuit

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

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

• 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

Lamp types

• recessed fixtures

• track lighting

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

• 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

• Rapid start– ballast quickly heats the mercury– 1-2 second response

• Instant Start– single pin at each end.– Ballast provides voltage start

• Compact fluorescent bulbs– energy efficient lighting

• High-Intensity Discharge lamps– halogen lamp is an example

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.

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

Inductive Reactance

• Equivalent to Resistance

• XL = 2fL – 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)

Capacitance

• Voltage is stored in electro-static field

• Plates separated by electrolyte

• RC time constant– t = RC

• Capacitive Reactance

• XC = 1/(2fC)– Measured in Ohms