EET 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 = 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 x 1000 x 200 x 10-3 = 1256  –L T 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/(2  fC) –Measured in Ohms