Light Sources: Incandescent and Halogen Lamps

The oldest electric light source still in common use, featuring a tungsten filament heated to produce visible light.

Usually tungsten, heated by electricity to produce light.

Most energy emitted by an incandescent lamp is in the infrared range, not visible light.

Measures how efficiently a light source converts energy into visible light.

Around 2800 Kelvin; perceived by humans as warm-toned light.

100; incandescent lamps accurately reproduce colors of objects.

Dimming reduces filament temperature, affecting color temperature, light output, and lamp life; longer life, lower light.

Compact fluorescent lamps (CFLs) come in various shapes, including twin tube, quad tube, and spiral lamps.

CFLs contain an electronic ballast that helps them start quickly and operate efficiently.

CFLs offer high efficacy (converting energy to light), good color rendering, low energy consumption, and a longer lifespan compared to traditional incandescent bulbs.

CFLs have a CRI ranging from 60 to 80, indicating their ability to accurately reproduce colors.

The light output of a fluorescent lamp peaks at an ambient temperature of 25°C. Below 15°C it decreases rapidly, and above 25°C it decreases at a slower rate.

The efficiency of converting energy into visible light in a fluorescent lamp is influenced by factors like circuitry, components, temperature, and frequency.

Using a high-frequency electronic ballast dramatically improves the luminous efficacy of fluorescent lamps.

Fluorescent lamp efficiency decreases with ambient temperatures above or below the optimum, but the decrease is less pronounced than the decrease in light output.

Operating a fluorescent lamp on a high-frequency supply increases its luminous efficacy by about 10%.

The gradual decrease in light output over time, typically measured after 6000 hours of use. This is due to the fluorescent powder's decreasing effectiveness and tube wall blackening.

A material coated inside the fluorescent tube that absorbs ultraviolet radiation and re-emits it as visible light.

A device essential for operating fluorescent lamps, it limits current flow to prevent the lamp from overheating and burning out.

The most common type of ballast, using an inductor (coil) to regulate current and produce the high voltage needed for lamp ignition.

Describes how well a lamp accurately displays the colors of objects. Measured using the Color Rendering Index (CRI).

The perceived warmth or coolness of the light emitted by a lamp, measured in Kelvin (K)

A type of fluorescent lamp emitting light with a warm, yellowish hue, typically around 2700-3000K.

A type of fluorescent lamp emitting light with a cool, bluish white hue, typically around 4000-4100K.

A type of fluorescent lamp emitting light that closely resembles natural daylight, typically around 5300-6500K.

A type of ballast that operates at a higher frequency, leading to less sputtering (material loss) and slower depreciation in fluorescent lamps.

More expensive but offer advantages over traditional ballasts. Features include improved efficiency, no flicker, instant starting, longer lamp life, better light regulation, higher power factor, less heat, no noise, lighter weight, and compatibility with DC power.

Electronic ballasts convert AC mains power into high-frequency square waves (20-100 kHz), which then pass through harmonic filters to reduce distortion.

The quality of an electronic ballast impacts the performance of the fluorescent lamp. A good ballast has a high power factor and low Total Harmonic Distortion (THD).

Cold fluorescent lamps have high resistance, requiring assistance to start. This is achieved through preheat starter circuits, preheat starterless circuits, or cold start circuits.

After ignition, a fluorescent lamp takes 2-3 minutes to reach full brightness. Its initial light output is about 60% of the final value.

Re-igniting a fluorescent lamp is usually effortless due to the rapid drop in vapor pressure after it's switched off.

Dimming fluorescent lamps can be achieved through thyristor (chopper) systems or variable frequency (HF) electronic light regulation.

The most recent development in fluorescent lighting, offering improved energy efficiency and performance.

Heat losses in ballasts result from the resistance of the windings and hysteresis in the core. These losses depend on the ballast's mechanical construction and the diameter of the copper wires.

An initial stage in the operation of a high-pressure mercury lamp where an electric field causes a faint, light-emitting discharge in the tube.

The main operating mode of a high-pressure mercury lamp, characterized by a concentrated, intense discharge and a high temperature.

The time a high-pressure mercury lamp takes to reach 80% of its full light output, primarily due to the vaporization of mercury in the tube.

The stable state reached by a high-pressure mercury lamp when all the mercury is vaporized and the discharge is in balance.

A device used to stabilize the current flow through a high-pressure mercury lamp due to its negative resistance characteristics.

Incandescent lamps have low luminous efficacy, meaning most energy is wasted as heat, not light.

Measures how accurately a light source renders colors, with 100 being perfect.

Dimming reduces the filament's temperature, leading to lower light output, cooler color, and longer lifespan.

Switching the lamp on and off is generally not harmful, but repeated switching can shorten the lifespan if the filament is weak.

Electronic ballasts offer significant benefits over traditional choke ballasts, including improved lamp efficiency, no flicker, instant starting, longer lamp life, better light regulation, higher power factor, less heat, no noise, lighter weight, and compatibility with DC power.

Electronic ballasts convert AC mains power into high-frequency square waves (20-100 kHz), which then pass through harmonic filters to reduce distortion.

The quality of an electronic ballast directly impacts the performance of the fluorescent lamp. A good ballast has a high power factor and low total harmonic distortion (THD).

Electronic ballasts offer significant benefits over traditional choke ballasts, including improved lamp efficiency, no flicker, instant starting, longer lamp life, better light regulation, higher power factor, less heat, no noise, lighter weight, and compatibility with DC power.

These lamps are resilient to voltage fluctuations, unlike other lamps which might fail prematurely or not function at all. They also have a universal burning position.

The time it takes for an extinguished high-pressure mercury lamp to restart after cooling down sufficiently. This time is generally around five minutes.

This lamp combines a high-pressure mercury discharge with tungsten filament light. The built-in ballast provides stability and blends the light output.

Similar to high-pressure mercury lamps but with added metal halides in their discharge tube. These halides contribute to a brighter and more vibrant light.

A Metal Halide lamp uses its energy for different functions, including light production, arc heating, and vaporization of metals.

A characteristic of high-pressure mercury lamps where the current increases as the voltage decreases.

Factors outside the lamp that can affect its performance, such as ambient temperature.

Changes in ambient temperature can influence the light output, lamp voltage, and lifespan of high-pressure mercury lamps.

Achieving a steady and stable operating state for the high-pressure mercury lamp, usually through the use of a ballast.