Lighting_Systems Flashcards
(25 cards)
What is a lumen?
A measure of the total amount of light emitted by a source.
What is a foot-candle?
The amount of light incident on a surface, measured in lumens per square foot.
Which lighting metric do architects typically focus on?
Foot-candles, because they indicate usable light at a surface.
What is luminous flux?
The total amount of light emitted by a source, measured in lumens.
Why does distance from a light source matter?
Because light spreads out over a larger area, reducing foot-candles.
What is the role of reflectors in lighting?
To focus light in a specific direction and increase foot-candle levels.
What is the role of diffusers in lighting?
To scatter light, which can reduce glare but also lower intensity.
What is an incandescent bulb?
A light source using a heated filament to produce light, now being phased out.
What are benefits of incandescent bulbs?
Fast turn-on, easily dimmable, inexpensive.
What is the primary drawback of incandescent lighting?
Inefficient and produces a lot of heat.
What does ‘A29’ mean in incandescent bulbs?
‘A’ refers to bulb shape; ‘29’ is 29/8 inches in diameter.
What is a fluorescent light?
A light that uses an electrical arc to excite mercury vapor and phosphors to emit light.
What is the function of a ballast in fluorescent lighting?
To regulate the electrical arc needed to excite mercury.
What is a CFL?
Compact Fluorescent Lamp, a small tube-based fluorescent bulb designed for incandescent sockets.
What are drawbacks of fluorescent lights?
Mercury content, disposal issues, cold sensitivity, and delayed full brightness.
What is efficacy in lighting?
The efficiency of a light source in delivering usable light (foot-candles).
What is a high-intensity discharge (HID) lamp?
A very efficient light source using gas discharge and phosphors.
What is the main issue with HID lamps?
Very slow startup time and poor color rendering in some types.
Why are HID lamps used in stadiums or gyms?
They produce high-intensity light and have long lifespans.
What is an LED?
A solid-state light source using light-emitting diodes; highly efficient and long-lasting.
Why are LEDs more efficient?
They can be placed closer to where light is needed and grouped in flexible patterns.
What are common applications of LEDs?
Task lighting, appliances, signage, general illumination.
What is an OLED?
Organic Light Emitting Diode, a flexible, thin light-emitting surface used in displays and possibly future walls/ceilings.
Why are LEDs replacing fluorescents and incandescents?
Longer life, better efficacy, lower energy use, and flexible applications.
