How to distinguish the positive and negative poles of SMD LED lamp beads

1. Look at the logo

1, T shape
Many SMD LEDs will be marked with corresponding logos, which are generally green, such as similar to the English letter "T". Many packages, such as some 0603, 0805 and other packaged SMD LEDs, will have a "T" symbol on the bottom. One horizontal side of the "T" is the positive pole, and the other side is the negative pole.

2. Triangle
Some SMD LEDs will be marked with a silk screen similar to a triangle symbol, so the bottom of the triangle is close to the positive pole, and the top corner of the triangle is close to the negative pole.

Second, look at the pins

The lead of the light-emitting diode is generally longer at the anode and shorter at the cathode.

Third, take care of the body shape

View the shape of the two lead wires in the tube from the side, the smaller one is the positive electrode, and the larger one is the negative electrode.

4. Pass the multimeter test

Set the multimeter to the "ohm x1" gear, when the diode is emitting light, the red test lead is connected to the positive end of the SMDLED, and the black test lead is connected to the negative end of the SMDLED.

Because the LED turn-on threshold is about 1.5-1.8V. It is possible that the voltage provided by the digital multimeter cannot start it. So still look at the mark. SMD LEDs have a green dot as the negative electrode and the opposite one as the positive electrode.

Five, look at the missing corner

In the LED energy-saving lamp lighting industry, 5050 SMD LEDs are often used. This SMD LED Lamp Bead is square. One of the four right angles has a small corner, and the end with the small corner is the negative electrode. The other end is the positive electrode.