How to judge the positive and negative poles of in-line light-emitting diodes?
A picture to quickly judge the positive and negative poles of the in-line light-emitting diode?
A picture tells you how to quickly judge the positive and negative poles of LEDs, including: judging the positive and negative poles of in-line LEDs, judging the positive and negative poles of SMD LEDs, judging the positive and negative poles of high-power LEDs, and judging the positive and negative poles of COB LEDs . This picture is equivalent to a guide for judging the positive and negative poles of LED light-emitting diodes, with one-to-one reference for in-line, SMD, high-power, and COB packages.
However, this "reference" is not as obvious as the traffic lights at the intersection. Because the professional requirements of LED electronics industry products are very standardized, if you only understand many meanings from the diagram, you will either feel that it is difficult to determine the specific package type, or there is no intuitive graphic description and it is easy to misunderstand.
How to find the package type corresponding to the light-emitting diode from the figure, and then judge the positive and negative poles of the corresponding light-emitting diode? Mainly still read by staring at the package features. There are mainly several types of packaging types for LED light-emitting diodes on the market.
In-line light-emitting diodes, patch-type light-emitting diodes, high-power light-emitting diodes, COB LED light-emitting diodes, of course, can be divided into red light-emitting diodes, blue light-emitting diodes, green light-emitting diodes and white light-emitting diodes by color.
Flat head plug-in LEDs: white light flat head plug-in LEDs, color light flat head plug-in LEDs... customized plug-in LEDs can meet various needs of direct plug-in LED applications
In-line light-emitting diodes have two views:
1. Look at the shape. Round, oval, straw hat, square, flat head, etc.
2. Look at the size. 3mm, 5mm, 8mm, 10mm, etc.
If you don't pay attention, you will feel that the shape and size have nothing to do with each other. Anyway, it is "plug-in" or "inline", so there is nothing to pay attention to, but when you choose the model, pay attention to the difference between size and shape.
For example, the straw hat type LED can only be made in 5mm, 8mm, 10mm, and the 3mm straw hat type can only be made.
In-line light-emitting diode positive and negative judgment
1: Judging by the length of the pins of the light-emitting diodes, the long pins are the positive pole, and the short pins are the negative pole.
2: By carefully observing the electrodes inside the tube, the smaller one is the positive pole, and the larger bowl-like one is the negative pole.
3: Judging by the internal structure of the light-emitting diode: the internal structure of the light-emitting diode has 2 pins, the larger end is the positive pole, and the other end is the negative pole. This can quickly judge the transparent colloid, because the internal structure of the misty colloid can not be seen clearly, and the positive and negative electrodes cannot be quickly identified.
4: Judging by the multimeter of the instrument: connect the red test lead to the positive pole of the light-emitting diode, and the black test lead to the negative pole of the light-emitting diode. When the light-emitting diode will glow normally, it means that the line is connected correctly and the positive and negative poles are judged correctly.
Therefore, facing the above method, it is easy to judge the positive and negative poles of the straight-inserted light-emitting diodes-of course, it is also very fast to use a multimeter to measure and judge, but generally you may not have a multimeter on hand, so you can first It is more reasonable to judge with a simple method, or you can first judge by observing the appearance or internal structure.
Of course, everyone will have their own judgment methods and ideas. The method in the figure below can be used as a reference. If you have a better method for judging the positive and negative poles of in-line LEDs, you can also contact me.
The above is the introduction of the positive and negative poles of the in-line SMD LED, more information on the positive and negative poles of the LED, and the specifications and prices of the in-line LED series
Welding method of LED lamp beads
There are many welding methods for LED lamp beads on the chip, and the following is one of the commonly used methods for reference. First, use an electric soldering iron to heat some soldering tin on the positive and negative electrode pads of the lamp bead (the soldering tin must not be too much, otherwise, the positive and negative electrode pads will be connected once heated with a hot-air gun), then use a hot-air gun to heat the positive and negative electrode pads at the same time, after the tin melts, use tweezers to place the positive and negative electrodes of the lamp bead on the corresponding pad.
LED beads change color? These six reasons are worth noting
LED is the light emitting diode, which is a semiconductor solid light emitting device that converts electric energy into light energy. Its core is the PN junction. In addition to the forward conduction, reverse cut-off and breakdown characteristics of the general PN junction, it also has the light emitting characteristics under certain conditions. Its structure mainly includes the following parts: lead, bracket, encapsulation glue, bonding wire, LED chip, solid crystal glue and phosphor. The discoloration failure of LED lamp bead is closely related to its material, structure, packaging process and service conditions. The following will analyze the causes of its discoloration through specific cases.
Common types and application fields of LED lamp beads
There are many kinds of LED light sources. Different LED lights have slight differences in the lamp beads used in their internal structures. Today, I will make a comprehensive and systematic scientific introduction to the common types of LED lamp beads for your reference.
LED lamp beads are also called light emitting diodes. It has a wide range of applications. Its luminous colors include red light, emerald green light, yellow green light, yellow light, purple light, blue light, white light and orange light. The above is monochromatic light. It can also be made into two or three colors.
How to identify whether LED lamp beads are pure gold
The gold wire used to package LED lamp beads contains more than 99.99% gold. It is produced by drawing gold from this material. In addition to 99.99% gold, this gold also contains less than 1% other trace elements. One of the core components of LED lamp bead packaging is gold wire, which is the bridge connecting the luminous chip and the welding point, and plays a decisive role in the service life of LED lamp bead. So how to identify the purity of gold thread?