What's it? IR Emitter or IR Receiver?

People usually call the IR LED (IR Emitter or IR transmitter) and IR Receiver (phototransfer and photodiode) together as an infrared transmitting LED pair. The shape of the infrared emitting LED is similar to ordinary round led emitting tube. It is more difficult to distinguish between the infrared transmitting led and the infrared receiving when you just start to use this IR LED Pair.

Generally, the judgment methods we can use are as follows:

First, use a multimeter to detect and identify the resistance between the electrodes of the IR LED to determine whether it is an infrared emitting LED.

(1) Change the test lead under the condition that the end of the infrared emitting tube is not exposed to light. The forward resistance of the emitting tube is small and the reverse resistance is large. When the black test lead is connected to the positive electrode, the lower resistance is the IR LED. The IR Receiver is the one with large forward and reverse resistance.

(2) When the black test lead is connected to the negative electrode, the IR LED is the transmitter tube with a large resistance. When the resistance is low and the pointer of the three-purpose meter changes with the light intensity, the pointer swings is the IR Receiver.

Then the power-on test method distinguishes the IR LED Emitter.

5mm ir transmitter and ir receiver IR Pair LED

We can first use an IR LED Emitter, a resistor in series with the IR LED Pair under test, and the LED emitter is used to display the working status of the IR LED under test. Use the remote control to press any key of the remote control to the tested LED. When the LED is on, the tested LED is Receiver. If it is not on, it is the IR LED emitter.
Detecting the operating current of the IR LED's operating voltage on the transmitter circuit can easily determine its operating performance. When detecting the working voltage at both ends of the LED, it is usually zero under static conditions, and will jump to a smaller voltage value under dynamic conditions. This voltage value is usually due to the encoding method of the remote control system, the structure of the drive circuit and the operating power supply voltage. Between 0.1 and 0.85V. If the value is not between these or too much difference, it can be judged that the IR LED is working abnormally. If the drive amplifier circuit is normal, the IR LED is mostly damaged.
Infrared LED should be kept clean and in good condition, especially the spherical emitting part of its front end must not contain dirt or other contaminants, let alone be damaged by friction. The infrared light emitted from the tube core will produce reflection and scattering phenomena, which will directly affect the propagation of infrared light. The lighter one may reduce the sensitivity of the remote control and reduce the control distance, and the severer may cause malfunction or even the remote control failure.

For IR LED pair, there have types like SMD LED package type and through-hole LED type are available. And at the same time, the lens on the ir receiver can also be white clear, black, deep blue as your required. There are the clear lens as follow:

3528 SMD LED PLLCC2 IR Receiver

For the IR LED, there have some other package do available such as: 940nm LED , 850nm LED or other IR LED wavelength with LED Lamps package: 5mm Through-hole LED, 3mm DIP LED , Cylinder LED ect. SMD LED package with 3528 SMD LED, 5730 SMD LED, 2835 SMD LED, 3014 SMD LED, 5050 SMD LED or High Power IR LED ect.

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