How to identify LED terminals?

Question

Hi everyone,I'm working on a school project that involves LEDs. I came across an LED where both the anode and cathode leads are of equal length, making it difficult to distinguish between them using the typical lead length method. Additionally, the internal structure of the LED is not visible. What are some reliable methods or techniques I can use to accurately identify the anode and cathode terminals in this situation?

Sebastian · Answer

Hi Aiden,To identify the anode and cathode of an LED, start with a visual inspection. Typically, the longer lead is the anode, and the shorter one is the cathode. If this method is not possible, another helpful visual indicator is the presence of a flat spot on the LED’s rim, which marks the cathode. If the internal structure is visible, the larger metal piece (die) inside the LED is connected to the cathode.If visual cues are unclear, electrical testing can be performed. Using a multimeter set to diode mode, place the probes on the leads; a reading will indicate that the anode is connected to the positive probe. Alternatively, you can connect a battery and resistor, attaching the positive terminal to one lead. If the LED lights up, the connected lead is the anode. hope this will help