How does the LED placement lamp distinguish the positive and negative poles? There is no sign on the light. Thank you
You can also use the ohmmeter's ohmmeter. To dial multimeter, to "ohm X1" file, the light emitting diode when the red pen is connected to the positive terminal of SMD LED, the black probe is connected to the negative terminal of SMD LED.
The light emitting diode is fixed regardless of color. The light emitting diode 1, line: foot length is positive, the negative is short. The electrodes inside the tube can also be carefully observed, while the smaller ones are positive and the large ones, similar to the bowl, are negative. 2, SMD: overlooking the side with the color line is negative, the other side is positive.
Because the LED open threshold is about 1.5-1.8V. It is possible that the voltage supplied by the digital multimeter does not activate it. So look at the sign. Patch LED (SMD LED), the green point of negative, relative to the positive.
