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1【luminous flux】In photometry, luminous flux or luminous power is the measure of the perceived power of light. It differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light.
2【Illuminance】In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.
3【Luminous efficacy】Luminous efficacy is a measure of how well a light source produces visible light. It is the ratio of luminous flux to power. Depending on context, the power can be either the radiant flux of the source''s output, or it can be the total power (electric power, chemical energy, or others) consumed by the source. Which sense of the term is intended must usually be inferred from the context, and is sometimes unclear. The former sense is sometimes called luminous efficacy of radiation, and the latter luminous efficacy of a source. (Lm/w)
4【color rendering index】The color rendering index (CRI), sometimes called color rendition index, is a quantitative measure of the ability of a light source to reproduce the colors of various objects faithfully in comparison with an ideal or natural light source. Light sources with a high CRI are desirable in color-critical applications such as photography and cinematography.[1] It is defined by the International Commission on Illumination as follows.
Color rendering: Effect of an illuminant on the color appearance of objects by conscious or subconscious comparison with their color appearance under a reference illuminant
5【Light attenuation】Light attenuation determines how fast the light intensity decreases with distance from objects. 100% is the default and corresponds to the traditional A: M light attenuation. The traditional A:M light attenuation is quadratic, meaning that the light intensity decreases proportionally to the square of the distance increase. Other useful attenuations are common such as linear where light intensity decreases at the same rate as the distance increases and constant where light intensity never decreases. By setting the attenuation to 50%, the attenuation is linear and at 0% the light attenuation is constant. Values between 0% and 50% will results in attenuations between constants and linear and values between 50% and 100% will result in attenuation faster than linear but slower than quadratic.
6【Color temperature】Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, horticulture, and other fields.
7【Glare 】Glare is difficulty seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as car headlamps at night. Because of this, some cars include mirrors with automatic anti-glare functions. Glare is caused by a significant ratio of luminance between the task (that which is being looked at) and the glare source. Factors such as the angle between the task and the glare source and eye adaptation have significant impacts on the experience of glare.
8【Power Factor】The power factor of an AC electrical power system is defined as the ratio of the real power flowing to the load to the apparent power in the circuit, and is a dimensionless number between 0 and 1. Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power will be greater than the real power.
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1.Protection Tube：When circuit element abnormality occurs, protection tube disconnect the line between the lights and the grid so as to stop fire appear as well as prevent smoke and other dangerous things happening.
2.Bipolar junction transistor, inductance and capacitance：Bipolar junction transistor, inductance and capacitance determine Good materials can make the lights normally used for 2-3 years while bad materials damage the components after the used of 7-8 month so that the lights cannot be used.
3.Bipolar junction transistor(BJT)：BJT is a type of transistor that relies on the contact of two types of semiconductor for its operation. It can be used as amplifiers, switches, or in oscillators. BJTs can be found either as parts of integrated circuits.
4.Electrical Ballast：Electrical ballast is a device intended to limit the amount of current in an electric circuit. A familiar and widely used example is the inductive ballast used in fluorescent lamps, to limit the current through the tube, which would otherwise rise to destructive levels due to the tube''s negative resistance characteristic.
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