Detection of infrared receiving diodes

1. Identify pin polarity

a. From the appearance, common infrared receiving diodes have a black color. When identifying pins, facing the light receiving window, from left to right, there are positive and negative poles respectively. In addition, there is a small oblique plane at the top of the infrared receiver diode, usually with one end of the pin as the negative electrode and the other end as the positive electrode.

b. Place the multimeter in the R × 1k range and use the method to distinguish the positive and negative electrodes of a regular diode for inspection, that is, exchange the red and black probes twice to measure the resistance value between the two pins of the diode. Under normal conditions, the obtained resistance value should be one large and one small. Based on the smaller resistance value, the pin connected to the red probe is the negative terminal, and the pin connected to the black probe is the positive terminal.

2. Check the quality of performance

Measure the forward and reverse resistance of the infrared receiving diode with a multimeter resistor. Based on the magnitude of the forward and reverse resistance values, the quality of the infrared receiving diode can be preliminarily determined.