Visible spectra of LED
The light is electricity radiation At some wave length extend. The wide spectrum of electricity radiation’wave length
-the shortest wave length is universe –rays.Its wave length is only 10-15 metre. The longest wave length is AC electric.Its wave length is up to thousands of kilometer .In this range ,
in about 380nm to 780nm is visible light. the other is invisible. for one,Gamma and X-rays are high-energy invisible light.

How to calculate.the current of led strip?
Examples are adopt SMD5050 encapsulation,A total of 60 pcs led,3pcs led divide into pairs,Each Group contains a resistance. Input voltage as 12V, powe is 12W. Do you know how much current Each LED has ?
Let’s break the question down:

1、60 PCS led module, 3pcs led divide into pairs,which means Tell us about the A total of 20 groups.

2、Input voltage is 12V, 3pcs led divide into pairs, Each Group contains a resistance. The means is total of 20 groups to parallel connection

3、Total power as 12W,That’s the single strand of led strip’power just has 0.6W

4、Because the led strip was parallel connection , so That’s the single strand of led strip’voltage as 12V.

5、We finally arrived at the conclusion that. Single led module current = 0.6W÷ 12V = 50mA

SMD LED strip and diode LED
SMD LED strip is made from FPC(Flexible Printed Circuit board) and SMD led. The lighting LED is a way of low voltage safety lighting, which needs the reasonable LED drive power supply. Its advantages include high brightness ,long afterglow, more colors and excellent performance. The key of high strength and multicolor decoration cloth was strength and brightness. We are thought it was the best choice for decoration, It is also used to Advertising decoration the cities bright engineering, the building outline of city’s delineation, and the night view decoration etc.
Characteristics:
* Randomly to bend up and down, and fix on any surface of concavoconvex;
* Compact size, rich color.
*With a high brightness, can adjustable lighting angle,
*Reasonable structure, convenient installation, easy operation and maintenance and reliable performance.
* Length can be customized according to the requirements
* Service time long
LED （light emitting diode）
Characteristics:
*Input voltage: Low voltage driver
* Input current: work current at 0—15mA，The increase of current results in the increase of LED’bright.

* Energy dissipation: Energy dissipation of incandescentsLED use about 80% less energy than an incandescent bulb. for example:Replace five incandescent light bulbs in your home with compact fluorescents: Swapping those 75-watt incandescents with 19-watt CFLs can cut 275 pounds of CO2.

Encountered every kind of difficulty in adjusting a color temperature,
Many book was introduced the adjusting led color temperature, This solution is easy to implement, with no programming needed. but it also have some problems and shortcomings. It is high time we discussed the problem.
The engineer is the last thing that color temperature offset or led turning dim and bright when adjusting LED color temperature.
Professionally, There’s hope adjusting a color temperature and adjusting a color bright don’t interfere each other. Only in this way can we achieve some new types of lighting environment can be assembled. The common methods still have difficulties meeting this requirement.

Ir led strip attenuation Does the cause that cause have those?

The is infrared radiation proportional to the light radiation power .the change of the size of signal output by light radiation power as direct。this could lead to ir led strip output changes. In other words, The infrared radiation would be affected, but very slightly.There are several reasons for Ir led strip attenuation。

(1)The light source is gradually getting Ageing，light radiation power is declined and output signal got it low 。
(2) The resistance value of light source is correct or not.
(3) The input power plug.’ Oxidation can cause contact problems.

Measurement results ultraviolet led light and Blue led light
Because ultraviolet light has a shorter wavelength than other led light .so Ultraviolet led light too weak to Glow.If you want to gain that facular concentrated, high brightness, and no stray light, no black hole, no shadow or dark areas. The technology are very difficult. it uses only ordinary Reflection bowl and lens.

we think in terms of more than 4pcs lens solution to the question of ultraviolet led light.

How Are led power supply Classified?

The led power supply are drive methods in sorts

Constant current mode:

*This is the best drive way on the led power supply, The chief objection to this drive way is prices higher.
*In load circuit, Circuit of Constant current can supportshort circuit, A ban on stuck-open.
*We know law of energy conservation. According to law of energy conservation that current output is constant in current output mode. the output voltage which change with current is large enough.
*In Constant current mode there is a minimum LED number limit. Echo led power supply has maximal loading capacity of current & voltage .

Constant voltage mode:
*Output voltage is fixed when determination of the constant voltage control circuit parameters. The law of energy conservation same will apply in constant voltage mode. the output current which change with output voltage is large enough.
*In load circuit, Circuit of Constant voltage can support stuck-open, A ban on short-open.
*The voltage changes will influence brightness in the LED after rectification
*Configure the appropriate to Control of the Uniformity of Luminance of LED in constant voltage mode

Considerations for Handmade weldability of SMD LED

Many factories were equipped without this wave soldering or mounting. using only the Handmade weldability of SMD LED. Working in this way, should pay attention to what?

1、The melting products but should be maintained as low as possible. Temperature of Welding Gun is 280° C-300° C lower than use Welding Gun as usual。solder wire with a melting temperature of about 220°.Suggested the Temperature of Welding Gun as far as possible low.

2、Notice the speed wants quickly ，weldability speed will rise about four times is best way. Welding Gun and solder wire blend should very tacit, must undertake the training of technicality, carry out very hard in the practice otherwise. That means, should send solder wire to Welding Gun right off, when Temperature of Welding Gun reaches 180°, Try to avoid extended periods of time at the SMD LED.

The voltage and current of LED

First we have the introductions

the yellow(585-595nm)﹑Red(600-650nm) and green(565-575nm) :

Their voltage is 1.8~2.4V(outside the range).and the vavg as 2.0v.

The blue(585-595nm)﹑green (600-650nm) and write(565-575nm) :

Their voltage is 2.8~4.0V(outside the range).and the vavg as 3.3v.

Problem of LED heat dissipation

This is an important part of design of led . because problem of heat dissipation. can even affect the length of LED life，also led to the falling of the reliability of the system .so Solving the heat of LED is the technical problem . Several misunderstandings about the optimization in problem of heat dissipation are analyzed .

Analysis for the misunderstanding in LED heat dissipation
1、Inefficient internal quantum-mechanical。cannot guarantee a 100% that produces photons When ecombination of photogenerated holes and electrons. incomplete parts must be translated into heat.
2、Internally generated photons will should not be total amnesty。In this section, incomplete parts also must be translated into heat.
3、The user can reduce excessive reliance on Conductive Materials .
4、Over use of heat shrink tube. But overusing the heat shrink tube has brought the heat damage to the led product.