How's IR LED and IR Transmitter LED Work?

When using IR LED with SMD LED type or through-hole LED type to control the corresponding controlled device, the control distance is proportional to the emission power. In order to increase the control distance of infrared rays, the IR LED works in a pulsed state, because the effective transmission distance of pulsating light is proportional to the pulsed wind-induced current, only need to increase the peak value Ip as much as possible to increase the emission distance of infrared light.

The method to increase Ip is to reduce the pulse duty cycle, that is, compress the pulse width T. Reducing the pulse duty cycle can also greatly increase the emission distance of the low-power infrared light-emitting diode.

The power of ordinary infrared light-emitting diodes is divided into three categories: low power, medium power and high power. To make infrared light-emitting diodes produce modulated light, only a certain frequency pulse voltage is applied to the drive tube.

When the infrared Light Emitting Diode emits infrared rays to control the controlled device, there are corresponding infrared photoelectric conversion elements in the controlled device, such as infrared receiving diode, infrared receiving head, photosensitive triode, etc.

There are two ways of IR LED and IR Transmitter LED, namely direct and reflective. The direct type means that the luminous IR LED Emitter and the IR Receiver are relatively placed at the two ends of the transmitter and the controlled object, with a certain distance between the middle; the reflective type means that the IR LED Emitter and the IR Receiver are arranged side by side, the receiving tube is always without light, only the infrared emitted by the IR LED When the light meets the reflector, the IR Receiver diode will only work after receiving the reflected infrared light. The dual-tube infrared emission circuit can increase the emission power and increase the range of infrared emission.