Detection of infrared receiving diode — SUNMATE

Detection of infrared receiving diode

A. Identify pin polarity

(a) Identify from the appearance. The appearance color of the common infrared receiving diode is black. When identifying pins, face the light receiving window, from left to right, they are positive and negative respectively. In addition, there is a small chamfer plane on the top of the tube of the infrared receiving diode. Usually, the pin with one end of the chamfer plane is the negative pole and the other end is the positive pole.

(b) First, use a multimeter to identify the positive and negative electrodes of ordinary diodes for inspection, that is, exchange red and black probes to measure the resistance between the two pins of the pipe twice. When it is normal, the resistance value obtained should be one large and one small. The smaller one shall prevail. The foot of the red probe is the negative pole, and the foot of the black probe is the positive pole.

B. Check the performance. Measure the forward and reverse resistance of the infrared receiving diode with the multimeter resistance block. According to the value of the forward and reverse resistance, the infrared receiving diode can be preliminarily judged.