Both pm2.5 laser sensors and pm2.5 infrared dust sensors belong to photoelectric sensors and are used to detect the concentration of dust particles in the air. However, their internal structures are very different, leading to differences in measurement accuracy. Let us compare the internal structures of pm2.5 laser sensors and pm2.5 infrared dust sensors.

Internal structural comparison between dust laser sensors and dust infrared sensors:

1. Laser sensors use a more stable laser diode as the light source, while infrared sensors use infrared light-emitting diodes (LEDs).

2. To drive air through the intersection area between the light source and the receiver, infrared sensors use resistive heating to drive the surrounding gas flow with hot air; laser sensors are equipped with a fixed internal fan to create airflow.

3. Regarding signal output, most phototransistors inside infrared sensors can only output Pulse Width Modulation (PWM) signals. These signals do not intuitively display the concentration of particulate matter and require further calculation to derive the concentration range; photodetectors inside laser sensors generate current signals through the photoelectric effect, which, after amplification and processing, provide specific concentration values, usually output via a serial port.

This explains why some purifiers can only indicate air quality through different colored lights, while other purification products can display the specific air quality index in digital form.

Different types of sensors have different performance and costs. Infrared dust sensors are cheaper than laser dust sensors. This also explains why some purifiers can only indicate air quality through different colored lights, while other purification products can display the specific air quality index in digital form.