How to distinguish between the pin diagram of the infrared receiver and the amplifier circuit?
The principle of the infrared receiving head is that the infrared monitoring diode monitors the infrared signal, and then sends the signal to the amplifier and the 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.
The infrared receiving head is an integrated receiving head composed of an infrared receiving tube and an amplifying circuit. The amplifying circuit is usually composed of an integrated block and a plurality of resistors and capacitors, and needs to be packaged in a metal shielding box, so that the circuit is complicated and the volume is small.
There are many types of infrared receivers, and the pin definitions are different. Generally, there are three pins, including power supply pins, grounding and signal output pins. The receiving head of the corresponding demodulation frequency should be selected according to the difference of the modulated carrier at the transmitting end.
Because the engineering process is to insert the board after spot welding, the project needs to understand the pins of the infrared receiver to make the pins correctly pair the board. So how do you identify the three pins of the infrared receiver?
There are generally two methods, the first one is the simplest, let the infrared receiver supplier provide the model specification, through the specification to distinguish the pins of the receiver. The other is to use the mechanical meter to measure the resistance of the two pins, find the one with the lowest resistance of the two pins. At this time, the watch stick should not move. The red watch stick is connected to Vcc, the watch stick is grounded, and the other pin is the signal pin(IR).
The three pins of the infrared receiver are GND, Vcc, and Out pins, which are ground, power, and signal outputs. Different types of infrared receivers have different pinouts.
The gain of the internal amplifier of the infrared receiving head is very large, which is easy to cause interference. Therefore, the VCC (voltage) PIN pin and the GND (ground) pin of the receiving head must be added with a filter capacitor. The expert test test is generally performed on a 47uf ceramic capacitor ( Note: Adding a capacitor to a 100uf or 20UF capacitor will cause the receiver to receive a short distance.
Infrared integrated receiving head: The infrared receiving head is generally a receiving, amplifying and demodulating integrated head. After the infrared signal is demodulated by the receiving head, the difference between the data “0” and “1” is usually reflected in the length of the high and low level or During the signal cycle, when the MCU decodes, the output pin of the receiving head is usually connected to the external interrupt of the MCU, and the time of the external interrupt interval is judged by the timer to obtain the data. The point is to find the difference in waveform between the data "0" and "1". The output can be connected to CMOS and TTL circuits. This type of receiver is widely used in air conditioners, TVs, VCDs and other electrical appliances.
If you want to know more, our website has product specifications for the infrared receiver and the amplifier circuit, you can go to ALLICDATA ELECTRONICS LIMITED to get more information