Common cathode nixie tube is a kind of digital display screen. By inputting relative current to different pins, it will make it light up, thus showing that the number can display all available digital parameters such as time, date, temperature and so on. Because of its low price, simple use, it is widely used in electrical appliances, especially in the field of home appliances, such as air conditioners, water heaters, refrigerators, and so on. Most water heaters use digital tubes, and other home appliances also use LCD screens and fluorescent screens.

      Find public common cathode and public common anode: We find a power supply (3 to 5 volts) and a 1k (a few hundred ohms) resistor, and then connect a resistor in series with vcc and connect it to any 2 pins with gnd, There are many combinations, but there is always one LED that will emit light. It is enough to find one, then gnd does not move, and vcc (string resistor) touches the remaining pins one by one. If there are multiple LEDs (usually 8), then it It's a total yin.

      On the contrary, use vcc without moving, and gnd touches the remaining feet one by one. If there are multiple LEDs (usually 8), then it is a co-yang. You can also use a digital multimeter directly. The red test lead is the positive pole of the power supply and the black test lead is the negative pole of the power supply.