SMD light-emitting diodes are actually very common in daily life. There is a more familiar title for this component, which is SMD LED. There are a large number of large screens, signal lights, and decorative lights. Applied. So, how to distinguish the positive and negative poles of SMD LEDs? What are the classifications of SMD LEDs?

How to distinguish the positive and negative poles of SMD LEDs

There are some signs near the pole piece pins, such as cutting corners, painting colors, or different pin sizes. Normally, there are signs, small pins, and the short side is the cathode (that is, the negative electrode), and the size is small 0805, 0603 package has "T" shape or inverted triangle symbol on the bottom

One horizontal side of the "T" is the positive pole; the "side" of the triangle symbol is close to the positive pole, and the "corner" close to the negative pole.

What are the classifications of SMD LEDs

By color

According to the luminous color of the luminous tube, it can be divided into red, red, orange, green (subdivided into yellow-green, standard green and pure green), blue light, white light and so on. In addition, some light-emitting diodes contain chips of two or three colors.

Depending on whether the light emitting diode is doped or not doped with a scattering agent, colored or colorless, the above-mentioned light emitting diodes of various colors can also be divided into four types: red, colored, transparent, colorless, transparent, colored, and colorless. Scattering light-emitting diodes and up to be used as indicator lights.

Under ordinary conditions, diode manufacturers use red, green, and blue SMD diode display screens. As for lighting, white LEDs are more commonly used.

By scatter

(1) High directivity. It is usually a pointed epoxy package or a package with a metal reflective cavity, and no scattering agent is added. The half-value angle is 5°-20° or less. The rectifier bridge has high directivity and can be used as a part of the lighting source, or combined with a light detector to form an automatic detection system.

(2) Standard type. Usually used as indicator light, its half-value angle is 20°～45°.

(3) Scattering type. This is an indicator light with a larger viewing angle, the half-value angle is 45° to 90° or more, and the amount of scattering agent is larger.

According to current

According to the luminous intensity and working current, there are ordinary brightness LEDs (luminous intensity 100mcd); the luminous intensity between 10-100mcd is called high-brightness LED. The working current of ordinary SMD diodes is more than ten mA to tens of mA, while the working current of low-current LEDs is below 2 mA (the brightness is the same as that of ordinary light-emitting tubes)

In the above, I have introduced how to distinguish the positive and negative poles of SMD LEDs and what are the classifications of SMD LEDs. The color classification of SMD LEDs is very rich. Basically, everyone's request can be reached. However, when using it, there is a very important information that everyone needs to pay attention to, which is required for SMD LEDs of different colors. There is a certain difference in voltage, and everyone must arrange the wiring at the time of installation.