LEDs are light emitting diodes. These are electronic components that produce light by conversion of electrical energy directly to light by the movement of electrons within the material of the diode.
LEDs have no gases, filaments or any moving parts to fatigue. They provide light through a one step process that takes place within the diode. There is no glass to break or screwed contacts to loosen.
Incandescent create light by use of a filament. When power is applied, the filament glows, generating heat, in turn, producing light. LEDs are the opposite. LEDs create light though a "cold process", when power is applied to semiconductors (usually gallium, arsenic and phosphorus) they're stimulated by the movement of electrons; thus creating photons, the light that is visibly seen by humans.
No, LEDs operate using entirely different components. LEDs are diodes; they only allow power to move in one direction. The anode (+) is where the current comes in and the cathode (-) is where the current goes out, much like the positive and negative terminals of a battery. Incandescent bulbs project light in every direction (omni directional) where LEDs due to their package design and layout, project light in specified directions such as 20, 50 or 120 degrees.
LEDs do not use a filament where a conductor is heated and light is created. Filament based lighting consumes more power than the light produced. LEDs produce very little amounts of heat and do not use filaments making them far more efficient in consumption and output.
LED's produce very little amounts of heat; the heat noticed in some instances is due to on board components and other factors of the circuit. In comparison to incandescent, LED's produce a fraction of the heat. If LEDs are hot to the touch, they are being overpowered due to improper circuitry.
LED's are geared for harsh environments. LED's function from -40 F to 180 F; there is no delay or required "warm-up" time for LED's to function.
LED's are rated by manufacturers to operate under normal conditions for approximately 10 years or 100,000 hours of continuous use. As LED's get older, they tend to dim and fade but aren't susceptible to blinking like incandescent or fluorescents.
LED's can operate as stand alone devices, but when grouped or clustered they require additional steps to operate properly. LED's need proper components such as a circuit board, driving components and some cases, housings; to endure the elements. LED circuits can be designed rapidly yes, but to ensure that they will operate correctly and for long periods of time they require testing.
LED light bulbs are much brighter than incandescent or halogen bulbs of the same wattage, but LED bulbs are not available in high wattages. Thus, when replacing incandescent or halogen lamps with LED lamps, more LED lamps are often needed. For example, to replace one 65-watt incandescent floodlight you may need two 6-watt or 7-watt LED floodlights. Although you have more bulbs you are still using 80% less electricity. Incandescent bulbs use about five times as much power to produce the same amount of light as LED bulbs. At low power levels the difference is larger. At higher power the difference is somewhat smaller. Electrical power is measured in watts. For example, a LED bulb consuming 3 watts might output light comparable to a 20-watt incandescent bulb, and a 6-watt LED bulb might be comparable to 30-watt incandescent bulb. Our brightest LED flood lamps use 11 to 12 watts and output light comparable to a 50-watt incandescent.
LEDs, having a longer life. Reduce maintenance and lamp replacement cost. This reduces cost of labour to replace lamps and the cost of new lamps at the end of lamp life cycle. LEDs, also consume less energy. Thus the overall cost of a LED system can thus be significantly lower than conventional lighting systems. Most applications with LEDs offer a payback period as low as 3-4 years.
The LED chip, or light engine produces heat. This needs to be dissipated as quickly as possible. This is normally by using a heat sink. This often has fins. Cool LEDs are more efficient than hot ones. They also have a longer life. Of course, higher power LEDs generally run hotter than low power ones because of the extra heat to remove.
Here are some aspects that need to be taken into consideration: when The luminaire spacing and layout. Preventing a view of the light source and minimising glare. Ventilation/cooling of LEDs Wiring access Access to LEDs in case of maintenance or replacement. Location of driver, if not integrated in luminaire. Switching/dimming or control type and location.
The lamp base / holder screw fixing position.The physical dimension of the LED lamp and how it fits into the existing housing. The electrical characteristics of LED's compared to the existing system. (mains voltage, low voltage, control methods). The location and size of the light emitting surface in relation to the luminaire reflector and in comparison to the original light source. The light distribution, lumen output and other photometric properties like colour temperature in comparison to the original light source. The heat generated by the LED during operation and the maximum operating temperature.
Most insects are primarily attracted to Ultra-violet rays to help them forage, navigate and select mates. LEDs do not have UV content and hence do not attract so many insects compared to conventional light sources.
LEDs have the following advantages over neon:
• Power consumption: LEDs use much less power required than neon to deliver the same light output.
• Versatility: LEDs offer a far wider a range of products and configuration of solutions than neon. Neon has limitation due the nature by which they produce light and fabricated.
• Heat dissipation: LEDs produce less heat than neon.
• Safety: Neon runs on high voltage and are unsafe to be located in places where public can touch.
• Neon uses fragile glass tubes.
• Colour range and effects: LEDs offer a wider palette of colour and colour changing effects through digital control.
• Maintenance: LEDs virtually need no maintenance compared to neon.
Not if they are completely enclosed. In order for an LED to function correctly, they must be in a non-enclosed fixture to allow for heat to dissipate from the heat sink. Otherwise, they can overheat and may fail early.
LEDs are low voltage devices. Hence they require a device / power supply unit / driver or integrated electronics that convert line voltage to low voltage to run the LEDs. Sometimes the driver has electronics that can interpret control signals to dim LEDs.
LED's are driven by constant current (350mA, 700mA or 1A) drivers or constant voltage (10V, 12V or 24V) drivers.
• Constant current drivers fix the current of the system and vary the voltage depending on the load of the LED.
• Constant voltage drivers require a fixed voltage and the LED loads are added in parallel across the output of the driver until maximum output currents are reached.
Constant current drivers are typically used in downlights where one, or a series, of luminaires used per driver. These are connected in series.
LEDs produce light by direct conversion of electrical energy to light energy. On the other hand, incandescent light sources produce light by heating a filament until it grows red hot. Linear and compact fluorescent lamps use a UV discharge plus a phosphor to produce the light. HID lamps use the ionisation of gases in a discharge tube which in turn produce photons.
No. LED's directly convert electrical energy to photons. It is a one step process of electroluminescence that does not require time to reach maximum output. Other sources such as fluorescents or HID work on discharge technology. This requires an arc to warm up and may take a few minutes to reach full output.
50,000 hours would imply 5.7 years if the light is operated for 24 hours in a day, 7.6 years if the lights are on 18 hours per day and 11.4 years for 12 hours a day.
Unlike conventional light sources that reduce in output and eventually fail, LED products do not normally suddenly fail. Instead, the light output reduces over time. The normal convention is to quote the life when the output has reduced by 30%. I.e. when there is 70% light output remaining. This is often quoted as the L70 life and is measured in hours.
Unlike discharge lamps, LEDs are semiconductors and their life span is not affected by the number of times they are turned on and off.
Typically, an LED will last four times longer than a CFL and 25 times longer than an incandescent source that puts out the same amount of light.
Sometimes simply comparing the lumen output of LEDs and conventional light sources may not be adequate. The amount of light falling on specific task area (the lux) gives a more realistic comparison. You should also consider the illumination on the walls. This helps identify applications where LEDs offer better solutions than other light sources.
In many cases when comparing the lumen output between LEDs and conventional light sources, LEDs may have lower lumen value However LEDs are directional light sources. All the lumens emitted from an LED are directed towards the task area; while conventional sources emit light in all directions which are then modulated in a given direction with optical systems like reflectors and lenses. The proportion of lumens that falls in the task area from an LED light source is greater than that of a conventional light source.