LED the important parameters of misgivings

1. Positive working current If

it is refers to the light-emitting diodes normal glowing positive current value. In the practical use should be according to the need to select the IF in 0. Under 6 · IFm.

　　2. Positive working voltage VF

parameters given in the table is the working voltage of positive electricity flow in a given. Is usually measured during the IF = 20 ma. Light emitting diodes are working voltage VF in 1. 4～3V。 At higher temperatures in the world and the VF will decline.

　　3. V - I feature

light-emitting diodes of the relationship between voltage and current in the forward voltage is less than a certain value ( Called threshold) When small current, light. When the voltage exceeds a certain value, after the forward current voltage increase rapidly, glow.

　　4. Luminous intensity IV

the luminous intensity of light-emitting diodes, often referred to as normal, ) refers to the axis of cylindrical light tubes The luminous intensity on the direction. If the radiation intensity in the direction of ( 1/683) W/sr, the luminous 1 candela ( Symbol for CD) 。 Due to the general LED luminous intensity is small, so the luminous intensity common candle, Candela, MCD) As a unit.

　　5.

- LED light-emitting Angle 90°- +90°

　　6. Spectrum halfwidth Δ lambda:

it said light-emitting tube spectral purity.

　　7. Half value Angle theta 1/2 and perspective

theta 1/2 refers to half of the axial intensity is a luminous intensity value direction and optical axis to ( The normal) The included Angle.

　　8. Holomorphy

according to LED solid Angle conversion from point of view, also called plane Angle.

　　9. Perspective

refers to the maximum Angle of LED, according to the Angle of view is different, have different application, also called the Angle of the light intensity.

　　10. A half

method to 0 ° and the Angle between the maximum luminous intensity / 2. Strictly speaking, is the maximum luminous intensity and maximum luminous intensity / 2 corresponding Angle. LED packaging technology, leading to the biggest light Angle is not normal light intensity value of 0 °, introducing the deviation Angle, referring to is the luminous intensity corresponding to the Angle of the largest and the method to the Angle between 0 °.

　　11. The biggest positive direct current IFm

to allow the biggest positive direct current. More than this value can damage the diodes.

　　12. The largest reverse voltage VRm

the biggest reverse voltage is allowed to add. More than this value, light-emitting diodes can be broken down.

　　13. Work environment topm:

light-emitting diodes working environment temperature range. Below or above this temperature range, light-emitting diodes will not work properly, the efficiency is greatly reduced.

　　14. Allow power Pm:

to allow for leds on both ends of positive dc voltage and current flow through the maximum value of product. More than this value, LED fever, damage.

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