For the diode gear of the digital multimeter, touch two pins with a stylus (test the first pin and the last pin, and test again if it doesn't light up; If it doesn't light up, change a needle and switch the stylus until a certain paragraph lights up), record which position and which paragraph lights up, and then remember that the red stylus is not moving. There are three ways to change a pin with a black stylus: 1. 2. On, a certain section in the same position (same constellation) as before is lit, and now the male * * * end of the red stylus can be determined, and this digital tube is * * * positive; 3. Bright is a section in the same position that is different from the previous bright position (another constellation). Which black stylus is connected to the male terminal (that is, the male terminal of the one that is on now), and this digital tube is female.
The male * * * terminal is generally controlled as bit selection. On the circuit board, whether to connect the power supply (* * * Yang) or the ground (* * * Yin).