LED and lighting FAQs

Below allows frequently asked questions, JLEDs receives about our products and services.

Click each of the questions to expand and view the answer.

What is an LED?

light-emitting diode (LED)is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.
When a light-emitting diode is forward biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor.
An LED is often small in area (less than 1 mm2), and integrated optical components may be used to shape its radiation pattern. LEDs present many advantages over incandescent light sources including lower energy consumption, longer life time, improved robustness, smaller size, faster switching, and greater durability and reliability. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output.
Light-emitting diodes are used in applications as diverse as replacements for aviation lighting, automotive lighting (particularly brake lamps, turn signals and indicators) as well as in traffic signals. The compact size, the possibility of narrow bandwidth, switching speed, and extreme reliability of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances.

What does Lumens mean?

The technical definition of lumen is as follows; A lumen is the standard measurement for a unit of luminous flux, it is a measure of the perceived power of light.

Why is looking at the Lumens output now important?

Most people are familiar with incandescent light bulbs that are measured in watts, for example you know what to expect from a 40w, 60w or 100w bulb. With LED Lighting, While you would automatically assume that higher wattage you use, the brighter the light you will get, it’s actually not really the way that it works. That’s because watts and lumens measure two very different things. A watt is a unit of electrical energy in other words, input. A lumen is a measure of light intensity output. More simply a light bulb uses watts to make lumens. As there are so many different types of LED chips each with different lumen outputs, you cannot now assume that for example all 4w LED lights offer the same lumen output. Different types of LED Chips are as follows; High Power LED Chip, Dip LED, Lamp LED, SMD, Flux LED, COB LED.

With LED Lighting being more directional than incandescent lighting, the lumens output to achieve the same brightness will be lower for LEDs than traditional lighting. A large percentage of the lumens output is wasted due to the directions in which the light is output.

LED Lumens efficiency

A standard 100 watt incandescent light bulb uses 100 watts of power to give around 1500-1700 lumens output, This is about 17 lumens per watt (17 lm/w). LED Replacement lamps offer even more lighting efficiency. some of the lights in our range are already offering over 90 lumens per watt and there are already some manufacturer making LED lamps that will put out 100 lumens per watt.

LED Glossary of Terms

Ampere (Amp) – the basic unit of electric current reflecting the rate of its flow. Current (Amps) = Power (Watts) / Voltage (Volts)

Candela, or cd – A candela is a measurement of the intensity of light and is used in the International Standard (SI) measurement system. Historically, a candela has been roughly equal to the intensity of the light emitted by a regular candle.

Color temperature – Colour temperature measures the colour of a light bulb and not the brightness. This is also used to indicate the ‘coolness’ and ‘warmness’ of a LED light source. Colour temperature is measured in degrees Kelvin and is a measure of the part of the colour spectrum that is found in light. A simple way to think about this is to compare the light from the sun from sunrise to sunset. At noon the light is bright and white, even more so nearer the equator. At sunrise and sunset the light takes on a more yellow or even red tint. Lower colour temperatures will have more yellow, and higher colour temperatures will go from yellow, to pure white and eventually to bluish, like you might find on some of the blue tinted headlights on cars. LED Lighting can produce a wide spectrum of Light, unlike their incandescent and halogen predecessors. However, the two main types of colours are Warm white (2750-3250k) and Cool white (6000k). Warm white resembles incandescent and halogen bulbs the closest.

Cool White – Is the colour described where the colour temperature is 5000k – 6000k. It is a bright white light that gives off a clinical feel suitable for areas such as offices and hospitals.

Color Rendering Index or CRI – the term used to describe the rendered color characteristic of an object. Generally the color looks more natural if CRI is high. Color Rendering Index is based on a scale from 0 to 100 (one hundred being used to characterize natural outdoor light). Cool white CRI is 62, and there are a number of other lighting sources with a variety of rates.

Controller – A device that controls the output of color-changing and tunable white lighting fixtures. Controllers typically have software components for configuring fixtures and designing and editing light shows, and hardware components for sending control data to fixtures.

Driver or ballast – An LED driver is a self-contained power supply that has outputs matched to the electrical characteristics of your LED or array of LEDs.

DMX – A digital communications protocol for controlling lighting fixtures, originally developed to control stage lighting.

Luminous Efficacy (or just efficacy) – the quotient of the luminous flux emitted by a source of radiation and the power it consumes, measured in lumens per watt (lm/W).

Lumen Output – The total lumens emitted of a light source, system, or solution.

Epoxy – tough resistant thermosetting synthetic resin often used to prevent optical decay in a dome or lens, but resulting in insufficient lumen maintenance over time. In the power light sources of Luxeon no epoxy is ¬