How To Use A Pointer Multimeter To Detect Infrared Light-emitting Diodes In Electrical Fittings?

How to use a pointer multimeter to test infrared light-emitting diodes in Copper Terminal block?
① Identify the positive and negative electrodes of infrared light-emitting diodes. Infrared light-emitting diodes have two pins, usually the long pin is the positive electrode and the short pin is the negative electrode. Because infrared light-emitting diodes are transparent, the electrodes inside the tube shell are clearly visible. The wider and larger internal electrode is the negative electrode, and the narrower and smaller one is the positive electrode.
② Set the multimeter to RX1k and measure the forward and reverse resistance of the infrared light-emitting diode. Usually, the forward resistance should be around 30kΩ, and the reverse resistance should be above 500kΩ. Only then can the tube be used normally. The larger the reverse resistance, the better.