How to judge the quality of the transistor and distinguish the type and pin?

Transistor is a basic and important device we encountered in the study of analog circuit, we must be familiar with the working principle of this device. Is this transistor good? How to quickly judge the polarity of the transistor, these problems are rarely introduced in the book, but every electronics practitioners or enthusiasts should grasp. Below by Positioning for you to identify the good or bad method of the transistor.

1. Distinguish the quality of the transistor

When we encounter problems in the process of circuit debugging, we often need to judge whether the pipe performance is good or not. At this time, we can use the three tables to judge. Adjust the transistor meter to the resistance level and measure the transistor's three pins in pairs for six times. If the resistance value can be measured for two times, it means that the transistor is good and the other situation is bad.

2. Audion type and pin discrimination

Adjust the multimeter to resistance;

Use the black pen of the multimeter to contact with no. 1 pin, and the red pen to contact no. 2 and no. 3 pin, respectively.

Use the black pen of the multimeter to contact with no. 2 pin, and the red pen to contact no. 1 and no. 3 pin respectively.

Use the black pen of the multimeter to contact with no. 3 pin, and the red pen to contact no. 1 and no. 2 pin respectively.

The above three groups of measurement, if a group of measurement are conducted, the black pen contact for the base, the audion is NPN type;

Using the diode file can distinguish the e, c two stages;

If none of the three groups of measurement are conducting, use a red pen as a common end, according to 2 to 4 steps of measurement, measured that the red pen is conducting a group of contact pin is b-pole, the audion is PNP, and then use the diode to judge the e and c pole.

Measurement of temperature rise of main power components

The measurement of temperature rise mainly includes the measurement of surface temperature rise of key power components such as MOS switch tube, transformer, output rectifier diode and output capacitor. The commonly used measuring instruments include infrared temperature meter and thermocouple meter.

The current situation of the market size of electronic components under the covid-19 epidemic

At present, China's output of electronic components has accounted for more than 39% of the world's total. The output of many categories of products, such as capacitors, resistors, electro-acoustic devices, magnetic materials, piezoelectric quartz crystals, micro-motors, electronic transformers and printed circuit boards, has accounted for the first place in the world. Among them, the output of electroacoustic devices accounts for 50% of the global output, and the output of micro special motors accounts for 60% of the global output.

Although China is a major producer of electronic components in the world, it is not a major producer of electronic components. In 2016, China's total import and export trade of electronic components reached us $72.378 billion, with a trade deficit of us $11.341 billion, which is still growing year by year. According to the market demand and investment consulting report of China's electronic components industry from 2016 to 2021, the sales revenue of China's electronic components accounts for less than 20% of the global total, and some high-end electronic components still need to be imported. Therefore, China's electronic components industry to grasp the initiative in the fierce international competition, we must strengthen the original innovation, integrated innovation and the introduction of digestion and absorption of re-innovation, at the same time, focus on the strength, key breakthrough, to create a number of enterprises with international competitiveness.

In recent years, China's electronics industry has continued to grow at a high speed, driving the strong development of the electronic components industry. The output of many categories of electronic components in China has ranked first in the world, and the electronic components industry occupies a very important position in the international market. China has become a world production base for electronic components such as loudspeakers, aluminum electrolytic capacitors, picture tubes, printed circuit boards and semiconductor discrete devices.

The rapid development of electronic information industry at home and abroad has brought a broad market application prospect to the upstream electronic components industry. The rapid start and development of automobile electronics, PDA, Internet application products, set-top boxes and other products will greatly drive the development of China's electronic components market. In the communication products, mobile communication, optical communication network, ordinary telephone, etc., all need a large number of components. In addition, computer and related products, consumer electronics and other areas of demand remains strong, which will become the driving force for the development of China's electronic components market. Based on the new characteristics of market demand, electronic components are developing towards the direction of ultra-micro, chip, digital, intelligent and green, and the development prospect of China's electronic components industry is optimistic.