What is a resistive transistor? The basic structure, working principle, resistance ratio, common models, applications, testing, operating procedures, and development history of resistive transistors

A Darlington Transistor is a special P6KE200A bipolar junction transistor (BJT) consisting of two transistors cascaded together. It has the characteristics of high current amplification factor and low input current, and is commonly used in application circuits that require high current amplification.

1、 Basic structure:

A band stop transistor is composed of two transistor cascaded together, where the first transistor is called the input stage (front stage) and the second transistor is called the output stage (back stage). The collector of the input stage is directly connected to the base of the output stage, while the collector of the output stage serves as the output terminal of the entire band stop transistor.

2、 Working principle:

The working principle of a resistive transistor is based on the conductivity characteristics of a PN junction. When the voltage between the emitter junction and the base is forward biased, the emitter junction will become conductive. At this point, electrons from the emitter will be injected into the base, forming a current. If a reverse bias voltage is applied between the collector junction and the base, the collector junction will enter a reverse bias state, thereby preventing current from passing through. Therefore, the amplification effect of a resistive transistor depends on the magnitude of the control base current.

3、 Resistance ratio:

The resistance ratio of a resistive transistor refers to the ratio between the base current (IB) and the collector current (IC), denoted as β. The typical value of β ranges from 20 to 1000, and different types of BJTs have different β values. The value of β determines the amplification capability of BJT, and a higher β value means a larger amplification factor.

4、 Common models:

Common NPN BJT models include 2N3904, 2N2222, BC547, etc. These models are low-power general-purpose BJTs suitable for most low-power applications. The characteristic of NPN BJTs is that the current direction between the base and emitter is the same.

Common PNP BJT models include 2N3906, 2N2907, BC557, etc. These models are also low-power general-purpose BJTs, suitable for most low-power applications. The characteristic of PNP BJTs is that the current direction between the base and emitter is opposite.

In addition to general-purpose BJTs, there are also some specialized models of BJTs, such as power type BJTs, high-frequency type BJTs, etc. These models have higher current and power processing capabilities, suitable for specific application areas.

5、 Application:

Band stop transistor is a special type of transistor, also known as bipolar thyristor. It is widely used in the field of electronics due to its strong controllability, fast switching speed, and low power consumption. Below are several common application areas of resistive switching transistors:

1. Power control: Resistive transistor are widely used in power switch control circuits. It can control the power switch, achieve fast switching and adjustment of the power supply, and improve power efficiency.

2. Dimming control: Bandstop transistors can be used in lighting dimming control circuits. By adjusting the conduction angle of the bandstop transistor, the brightness of the light can be adjusted.

3. Motor control: Resistive transistors can be used for speed control and steering control of motors. By controlling the switching state of the resistive transistor, it is possible to achieve forward, reverse, and speed control of the motor.

4. Variable resistor: A resistive transistor can be used as a variable resistor. By changing the conduction angle of the resistive transistor, the resistance value can be adjusted and controlled in circuits.

5. Inverter: Resistive transistors can be used in inverter circuits to convert DC power into AC power, and are widely used in fields such as solar power generation and electric vehicles.

6、 Testing:

The detection of resistive triodes mainly includes the following aspects:

1. Conducting voltage detection: Use the diode testing function of a multimeter to connect the test leads to the positive and negative terminals of a resistive transistor and measure the voltage. In the conducting state, the positive electrode voltage is low and the negative electrode voltage is high.

2. Resistance detection: Use the resistance testing function of a multimeter to connect the test leads to the two pins of a resistive transistor and measure the resistance. Under normal circumstances, the resistance of a resistive transistor should be within a normal range.

3. Function detection: By connecting a resistive transistor to the corresponding circuit, observe its working status. For example, connect to the power switch control circuit and observe whether the resistive transistor can control the power switch.

7、 Operating procedures:

1. Before operation, it is necessary to carefully read the specifications of the resistive transistor to understand its maximum current, maximum power, and other parameters, in order to avoid exceeding its rated parameters and causing damage.

2. Before connecting the circuit, it is necessary to determine the pins of the resistive transistor, which can usually be confirmed through specifications or information provided by the manufacturer.

3. When connecting circuits, it is important to pay attention to the correct polarity connection, as incorrect polarity connections may cause the circuit to malfunction or be damaged.

4. When using a resistive transistor, it is necessary to select the control current and operating voltage reasonably according to the specific application scenario to ensure that the resistive transistor can work normally.

5. When using a resistive transistor, attention should be paid to controlling the magnitude of the current. Excessive or insufficient control current may cause the resistive transistor to malfunction.

6. If it is necessary to replace or repair the resistive transistor, the power supply should be disconnected first and the correct steps should be followed to avoid damaging the circuit or components.

8、 Development history:

The band stop transistor was first proposed in the 1960s and has been widely studied and applied in the following decades. With the development of electronic technology and the increasing demand, band stop transistors have been continuously improved and perfected.

In the early stages of development, band stop transistors were mainly used in the fields of power control and dimming control. However, due to the poor controllability and stability of the band stop transistor, its application range and performance are limited.

With the advancement of technology, the controllability of resistive switching transistors has been improved, and the introduction of new materials and designs has made the switching speed of resistive switching transistors faster and the power consumption lower. At the same time, the reliability and stability of resistive switching transistors have also been improved, leading to their continuous expansion in various fields of application.

At present, the band stop transistor has become one of the indispensable components in the electronic field, widely used in power control, dimming control, motor control, inverters and other fields. With the continuous advancement of technology, the performance and application fields of band stop transistors will continue to be expanded and improved