Two Methods For Distinguishing Between Infrared LED Bead Emission Tubes And Reception Tubes

The emitting tube of the infrared LED bead and the receiving tube of the infrared LED bead are collectively referred to as the infrared LED bead pair tube. The shape of the infrared LED bead tube is similar to that of a regular circular LED bead. For those who are new to infrared LED bulbs, it is difficult to distinguish between infrared LED bulb emitting tubes and infrared LED bulb receiving tubes. The general judgment methods we can use are as follows:
1, Measure and identify with a multimeter
A multimeter can be used to measure the inter electrode resistance between the infrared LED beads and the tube to determine if it is an infrared LED bead.
Judgment 1: Under the condition that the end of the infrared LED bulb is not exposed to light, when measuring with a replacement probe, the forward resistance of the emitting tube is small, the reverse resistance is large, and when the black probe is connected to the positive pole (long pin), the emitting tube with the smaller resistance (1k-20k) is the infrared LED bulb. The receiver tube for infrared LED chips has high resistance in both forward and reverse directions.
Judgment 2: When the black probe is connected to the negative terminal (short pin), the infrared LED bead emitting tube has a higher resistance, while the infrared LED bead receiving tube has a lower resistance and the pointer of the multimeter swings with the intensity of light.
2, Power on test to determine infrared LED beads
We can first connect an LED bead and a resistor in series with the tested infrared LED bead to display the working status of the tested infrared tube. Press any key on the remote control (DVD remote control, etc.) towards the tested tube, and when the LED lights up, the tested tube is the receiving tube of the infrared LED bead. If it doesn't light up, it's the emission tube of the infrared LED bulb.
Measuring the operating voltage and current of infrared LED beads on the transmitter circuit can easily determine their performance. When measuring the working voltage at both ends of a tube, it is usually zero under static conditions (i.e. when no button is pressed), while under dynamic conditions (i.e. when a button is pressed), it will jump to a smaller voltage value. Due to differences in the coding method of the remote control system, the structure of the driving circuit, and the working power supply voltage, this voltage value is usually between 0.1 and 0.85V. If the values are not within this range or differ too much, it can be determined that the infrared LED chips are working abnormally. If the driver amplifier circuit is normal, it is mostly due to damage to the infrared LED chips.
Infrared LED chips should be kept clean and in good condition, especially the spherical emitting part at the front end, which should not contain pollutants such as dirt or be damaged by friction. Otherwise, the infrared light emitted from the chip will reflect and scatter, directly affecting the propagation of infrared light. Mild cases may reduce the sensitivity and distance of the remote control, while severe cases may cause malfunction or even remote control failure.