Active components refer to those electronic components that can actively generate signals, amplify signals, control currents, or perform data operations and processing. These components play a key role in the circuit and can change the shape, size or direction of the signal, etc.
1. Common active component classifications include Transistors - including bipolar transistors (BJT), field effect transistors (FET) and insulated gate bipolar transistors (IGBT), etc. It has good switching and amplification performance. Widely used in circuits such as amplification, switching, modulation, and voltage regulation
① Diodes - Depending on the material and process, diodes are of various types such as silicon diode conduction and germanium diodes Diodes have unidirectional conductivity and can be used for rectification and voltage limiting. It plays a role in circuit protection and extending circuit life in the circuit
② Transistors (semiconductor transistors) - Depending on the material, structure and working principle, diodes can be divided into various types, such as NPN type, PNP type, etc. It has the function of current amplification and is the core component of electronic circuits. It can be used to build various advanced circuits and systems such as power amplifiers and amplifiers
③ Operational amplifiers - According to different performance indicators and application scenarios, there are many types of operational amplifiers, such as general-purpose operational amplifiers, high-precision operational amplifiers, etc.
Operational amplifiers are analog circuits with high open-loop gain and input impedance. They are mainly used in signal amplification, filtering, analog calculation and other fields to realize the processing and transformation of input signals
④ Voltage reference sources - Common voltage reference sources include Zener diodes, voltage reference integrated circuits, etc. They can provide stable output voltages and are often used as voltage references for analog and digital circuits
⑤ Oscillators - Including RC oscillators, LC oscillators, quartz crystal oscillators and other types. They can generate stable oscillation signals and are widely used in communication, broadcasting, and real-time fields
⑥ Controllers - Common ones include microcontrollers (MCUs), programmable logic controllers (PLCs), etc. They can control circuits or systems and are often used to realize functions such as automatic control, remote control, and timing
Power management components - Including voltage monitors, current monitors, power switches, and other components that monitor and manage power systems. It can be used to realize the functions of voltage regulation, switching and protection of power supply
⑦ Photoelectric devices - including photodiodes, phototransistors, photocouplers and other components that convert light energy into electrical energy or convert electrical energy into light energy. Commonly used in photoelectric sensors, optical communications, solar cells and other fields
2. Working principle of active components
The working principle of active components is mainly based on the complex physical and electronic processes inside them. These processes include electron injection, recombination, drift and conductivity changes of semiconductor materials. These components usually contain one or more PN junctions, which will change the conductivity under the action of external voltage or current, thereby realizing the control of the circuit and signal amplification
For example, in a triode, when the base receives a weak input signal, it controls the current flow between the integrated electrode and the emitter, so that the collector current is much larger than the base current, thereby realizing signal amplification. In integrated circuits, various processing of input signals, such as operation, amplification, filtering, etc., is achieved through the combination of fine circuit structures and complex electronic components.
3. The role of active components
Active components play a wide range of roles in electronic circuits, mainly including the following aspects
① Signal amplification - Active components can amplify the amplitude or power of input signals so that these signals can be better utilized in subsequent circuit processing. For example, in audio amplifiers, active components such as triodes and integrated circuits are used to amplify audio signals to drive speakers to produce clear and loud sounds
② Signal control - Active components can control the flow and state of signals to achieve functions such as switching, rectification, and modulation. For example, in digital circuits, active components such as diodes and field effect transistors are used as switching elements to control the on and off states of the circuits and adjust the flow of signals
③ Signal processing - Active components can perform complex processing on signals, such as filtering, transformation, and operation. In integrated circuits, various complex signal processing functions can be realized through the combination of fine circuit structures and complex electronic components, such as image compression and decompression, data encryption and decryption, etc.
Energy conversion - Active components can also convert one form of energy into another form of energy. For example, in solar cells, photodiodes can convert light energy into electrical energy; in LEDs, they can convert electrical energy into light energy
4. Application fields and market demand of active components
Active components are widely used in various electronic devices, such as computers, communications, consumer electronics, industrial automation, etc. They are one of the key components to realize the functions of electronic devices and have an important impact on the performance, power consumption and reliability of electronic devices
① Computer field - The application of active components in the computer field is mainly reflected in microprocessors, memory chips, etc. The microprocessor is the core component of the computer, responsible for executing instructions, processing data and other tasks; the memory chip is used to store data and programs to ensure the normal operation of the computer
② Communication field - The application of active components in the communication field is mainly RF chips, baseband chips, etc. RF chips are responsible for signal transmission and reception; baseband chips are responsible for signal processing and transmission. With the continuous development of technologies such as 5G and the Internet of Things, the demand for active components in the communication field continues to grow
③ Consumer electronics field - The application of active components in the consumer electronics field is mainly reflected in smartphones, tablets, smart TVs, etc. These devices integrate a large number of active components, such as processors, sensors, cameras, etc., to achieve rich functions and convenient operation
④ Industrial automation field - The application of active components in the field of industrial automation is mainly reflected in sensors, controllers, etc. Sensors are used to detect various physical quantities (such as temperature, pressure, displacement, etc.); controllers control and adjust according to the output signals of sensors. With the continuous development of technologies such as intelligent manufacturing and industrial Internet, the demand for active components in the field of industrial automation continues to grow
⑤ Automobile - With the continuous development of automotive electronics, active components are increasingly used in automobiles. Components such as sensors and control chips are used to realize intelligent control and energy conservation and emission reduction of vehicles. For example, the engine control system senses the operating status of the engine through sensors, and accurately controls parameters such as fuel injection and ignition through control chips, thereby improving the performance and fuel economy of the engine
⑥ Medical equipment field - Medical equipment such as electrocardiographs, blood pressure monitors, and ultrasonic instruments all need to use active components to collect, process, and display data. For example, sensors are used to sense the patient's physiological parameters and convert them into electrical signals for processing; integrated circuits are responsible for realizing functions such as device control, calculation and communication.
