Watts & Electrical Power Flashcards
What are the three most basic units in electricity?
voltage (V), Current (I) and resistance (r)
How is voltage measured?
in volts
How is current measured?
in amps
how is resistance measured?
in ohms
resistance produces what?
light, heat or both
How is electrical powered measured?
in watts
A measure of amount of electrical “stimulus” needed to enable current to flow through a circuit is?
Volts
a majority of line-voltage lighting applications operate at?
120 volts
Some large scale commerical lighting applications operate at?
277 volts
low-voltage lighting applications usually operate at?
12 volts
A measure of quantity of electrical particle flow in a circuit
Amps
circuits having higher currents require?
larger wire sizes. circuit breakers and switches
what are lighting circuits rated at?
15-20 amps
measure of electrical circuits ability to do work
watts
what does an electrical circuit consist of?
voltage sourcce
resisstance or loads connected in a continuous loop
electrical conductors such as wires
control devices such as switches and safety devices designed to prevent electrical overloads such as circuit breakers
the U.S has how many voltages for buildings?
4
120/240-v single phase, 3 wire is primarily used where?
primary residential
120/280-V three phase, 4 wire is primarily used where?
commerical
277/480-V three phase, 4 wire is primarily used where?
commerical
2400/4160-v is primarily used where?
very large buildings
What is the equation to calculate watts-per-square-foot?
Watts per square foot=total watts / square footage
what is the lighting power factor equation?
total # of watts consumed/ total area of space being lit
