For example, convert to voltage. A temperature sensor can convert the temperature value to a voltage between 0V and 5V, such as 0.3V, 3.27V, 4.99V, etc. Since the sensor expresses an analog signal, it will not have simple high and low levels like a digital signal, but it may be any value between the two, and the number of possible values depends on the end. The accuracy of analog-to-digital conversion, the higher the accuracy, the more values you can get. The ADC (Analog to DigitalConverter) used by Arduino is called analog-to-digital converter. The accuracy of each analog-to-digital converter is 10bit, and it can read 1024 (2 ^ 10 = 1024) states. On each analog input pin of Arduino, the voltage change range is from 0V to 5V, so the minimum voltage change that Arduino can sense is 4.8 millivolts (5/1024 = 4.8mV).