Today, the small series of Hongjin Electronics will introduce you to the reason why the infrared receiving tube should be added with filter capacitors!

There are many types of infrared receiving heads of infrared receiving tubes, and their respective pin definitions are also different. The gain of the internal amplifier of the infrared receiving head is very large, which is easy to cause interference. Therefore, a filter capacitor must be added to the power supply pin of the receiving head, generally 22uf or more.

  When it comes to infrared receivers, everyone is not too strange. It should be visible everywhere in our lives. When you go back home and turn on the TV, will you use the remote control when you need to turn on the air conditioner? It is also needed at this time. It is a wireless, non-contact control technology with strong anti-interference ability, reliable information transmission, low power consumption, low cost, easy implementation, etc., and is used by many electronic devices, especially household appliances. Widely used, and more and more applied to computer systems, now every family will have some infrared remote control equipment, the most common is the TV remote control, other such as air conditioner remote control, DVD remote control, and us The infrared receiving head and the infrared receiving tube which are usually seen are all part of the infrared receiving device.

  The infrared receiving circuit of the infrared receiving head is usually integrated into one component by the infrared LED receiving tube manufacturer, and becomes an integrated infrared receiving head. The internal circuit includes an infrared monitoring diode, an amplifier, a limiter, a bandpass filter, an integrating circuit, a comparator, and the like. The infrared monitoring diode monitors the infrared signal and then sends the signal to the amplifier and limiter. The limiter controls the pulse amplitude to a certain level regardless of the distance between the infrared transmitter and the receiver. The AC signal enters the bandpass filter. The bandpass filter can pass the load wave from 30khz to 60khz, enter the comparator through the demodulation circuit and the integration circuit, and the comparator outputs high and low levels to restore the signal waveform of the transmitter. Note that the high and low levels of the output and the transmitter are inverted, in order to increase the sensitivity of the reception.