When the infrared receiving head emits infrared to control the controlled equipment, there are corresponding infrared photoelectric conversion elements in the controlled equipment, such as infrared receiving diode, infrared receiving head, photosensitive audio, etc.

　　The appearance of conventional infrared LED beads is similar to ordinary LED beads, but they produce infrared rays. Usually the voltage is around 1.4V, and the working current is generally below 20 mA. In order to adapt to different operating voltages, there are usually a series of limited current resistances.

　　 There are two ways to transmit and receive infrared rays: direct and reflective. Direct radiation means that the luminous tube and the receiving tube are placed on the opposite side of the transmitter and the controlled object, and there is a certain distance between the two. Reflection means that the luminous tube and the receiving tube are juxtaposed, and the receiving tube usually does not emit light. When the infrared emitted by the luminous tube meets the reflector, the receiving tube receives the reflected infrared. The dual infrared emission tube circuit can increase the emission power and infrared emission range.

　　 When using infrared LED lamp beads to control the corresponding control equipment, the control distance is proportional to the emission power. In order to increase the infrared control distance, the infrared emission tube is in the pulse balance state, because the effective emission distance of the pulsating light is proportional to the pulse balance induced current, so it is only necessary to increase the peak value Ip to the infrared transmission distance as much as possible. The method to increase Ip is to reduce the pulse ratio, that is, compress the pulse width T. By reducing the pulse ratio, the transmission distance of the low-power infrared emitting diode can be greatly improved. Generally, the power of infrared emitting diodes can be divided into three categories: low power, medium power, and high power. In order to allow the infrared emitting diode to produce adjusting light, only a certain frequency pulse voltage is added to the drive tube.