Electronic components are the basis for composing electronic products and mastering the types, structures, and properties of commonly used electronic components is the foundation of electronic technology.
What are Electronic Components?
An electronic component is also called an electronic device, or circuit element. A basic element in an electronic circuit, usually an individual package, with two or more leads or metal contacts. Electronic components must be connected to form an electronic circuit with a specific function, and one of the common ways to connect electronic components is by soldering to a printed circuit board.
Electronic components may be individual packages called discrete components. Alternatively, multiple electronic components and circuits are fabricated on the surface of a semiconductor wafer in a concentrated and miniaturized manner to form groups of various complexities, which are called integrated circuits.
To maintain the stability of the operation of electronic components, they are usually encapsulated with synthetic resin to improve insulation and protection from the environment.
- Passive components are electronic components that do not have any gain or directivity when in use. In-circuit analysis, they are called power components.
- Active components are electronic components that have gain or directionality when used relative to passive components, including semiconductor devices and vacuum tubes.
What are the Common Types of Electronic Components?
Resistors are often simply referred to as resistors, denoted by R. It is one of the most used basic devices in electronic circuits and electrical devices. The so-called resistance means that various conductive materials have a certain hindering effect on the electronic current flowing through them and convert the current energy into heat energy, and electronic components with resistance performance are called resistors.
Resistors are the most used electronic components in electronic circuits, and almost all electronic products are inseparable from resistors. Resistors are used in electronic circuits to step down, limit current, divide voltages and divide currents, and together with other components form circuits with various functions such as sampling, isolation, coupling, feedback, filtering, compensation, etc. The international unit of resistance is ohm Ω, and 1Ω means the resistance value of the resistance required to generate a current of 1A when a voltage of 1V is applied to the conductor. Resistors larger than ohms are KΩ or MΩ. The commonly used Ohm's law I=U/R.
There are many types of resistors, the most used are carbon film resistors, metal film resistors, metal oxide film resistors, glass glaze resistors, synthetic carbon film resistors, wire wound resistors, thermistors, photoresistors, voltage Varistor, Humidity Sensitive Resistor, Gas Sensitive Resistor, and Force Sensitive Resistor, Magnetic Dependent Resistor, Degaussing Resistor, Fusible Resistor, Cement Resistor, Adjustable Resistor, etc.
The capacitor is an energy storage element, which blocks DC and communicates with AC. It is often used to store electrical energy and is represented by C. Commonly used capacitors are marked with the nominal capacitance of the capacitor in uF, nF, and PF and the rated working voltage in V.
Capacitors can be subdivided into high-frequency bypass capacitors, low-frequency bypass capacitors, filter capacitors, tuning capacitors, high-frequency coupling capacitors, and low-frequency coupling capacitors. These include aluminum electrolytic capacitors, tantalum electrolytic capacitors, organic dielectric capacitors, paper dielectric capacitors, organic dielectric plastic film capacitors, and inorganic dielectric capacitors. These capacitors have their advantages and disadvantages. Among them, aluminum electrolytic capacitors are small and large in capacity but have poor high-frequency performance. They are generally used as filter capacitors or energy storage capacitors. Ceramic capacitors and monolithic capacitors have better high-frequency performance, but their capacity is not large, and are generally used as high-frequency filter capacitors. The functions of capacitors in electronic circuits include filtering, oscillation, frequency selection, and coupling.
Inductors (inductance coils), like transformers, are electromagnetic induction devices wound with insulated wires, and are also one of the most widely used electronic components. Inductors are often combined with capacitors in circuits for filtering, resonance, and frequency selection. In the DC-DC buck-boost circuit, the inductor can be used in combination with a triode or an integrated circuit to achieve a boost or buck.
Inductors are indispensable electronic components in household appliances, instrumentation, and other electronic products. Their functions are to isolate AC signals and filter or form resonant circuits together with capacitors and resistors. The letter element number of the inductor is L, the unit of its inductance is H, and the commonly used units are mH and uH. Inductors can be divided into high-frequency inductors, intermediate-frequency inductors and low-frequency inductors, high-frequency choke coils, and low-frequency choke coils according to the application field.
A transformer is a component made by winding two or more sets of coil windings on the same coil bobbin (or iron core) using the principle of electromagnetic induction, which is called a transformer. By changing the ratio of turns between the primary winding and the secondary winding of the transformer, the voltage ratio or current ratio of the two windings can be changed to realize the transmission and distribution of electrical energy (signal). The main function of the transformer in the circuit is to reduce or increase the AC voltage, couple the signal, transform the AC impedance, isolate, transmit electrical energy, etc.
There are many types of transformers, which can be divided into high-frequency transformers, intermediate-frequency transformers, and low-frequency transformers according to their operating frequencies. The literal element number of the transformer is represented by T. The parameters of different types of transformers are also different; for example, the parameters of power transformers include rated power, rated voltage and voltage ratio, operating frequency, and no-load current, no-load loss, insulation resistance, etc.
Semiconductor devices can be divided into semiconductor diodes and semiconductor triodes. Diodes are further subdivided into detector diodes, rectifier diodes, switching diodes, damping diodes, stabilizing diodes, varactor diodes, light-emitting diodes, photodiodes, and bidirectional shock diodes. Wear diodes, fast recovery diodes, Schottky diodes, unijunction transistors, etc.
There are too many types of crystal triodes, which are mainly divided into PNP type germanium materials, NPN type germanium materials, PNP type silicon materials, NPN type silicon materials, and compound materials. It is further divided into high-frequency triode, intermediate frequency triode, low-frequency triode, and so on. According to the power, it is divided into low-power triode, medium-power triode, high-power triode, Darlington composite transistor, etc.
- Thyristor and field-effect transistor:
The thyristor (SCR) has unidirectional conductivity, but it has completely different characteristics from the silicon rectifier element. The rectifier voltage of the thyristor can be controlled, and it can control a large rectifier power with a tiny milliampere current. In addition, the thyristor also has the advantages of fast frequency response speed, high rectification efficiency, and small size of its components.
Thyristors are widely used in power lines and control systems such as controllable rectification, non-contact switches, rectification, and inversion of frequency converters. The thyristors are subdivided into low-power thyristors, medium-power thyristors, and high-power thyristors. The thyristor has three electrodes, namely K (anode), A (cathode), and G (gate).
According to the classification of process structure, field-effect transistors can be divided into junction field-effect transistors and insulated gate field-effect transistors (MOS). According to the materials used in the conductive channel, field-effect transistors can be divided into two types: N-type channel and P-type channel.
The input impedance of the field-effect transistor is very high, which cannot be achieved by ordinary thyristors. Moreover, the field-effect transistor has low noise, a large dynamic range, and strong anti-interference energy, so it is an ideal voltage amplification switching device.
- Electronic tube and camera tube:
Electron tubes and camera tubes are both electronic vacuum devices, which have played a huge role in promoting the development of electronic technology. With the birth of semiconductor devices, the application field of electron tubes has gradually decreased. However, in the electronic vacuum device in the ultra-high frequency technology, the oscilloscope tube, and the picture tube in the display technology, etc., still use the electron tube as the mainstream.
- Piezoelectric devices and Hall devices:
The quartz crystal oscillator is made of the piezoelectric effect characteristics of the quartz crystal and belongs to an electric resonance component. It is widely used in various communication devices, computer CPUs, microcontrollers, and remote-control devices. In addition to quartz crystals, there are ceramic filters, surface acoustic filters, piezoelectric buzzers, etc.
Hall devices are electromagnetic components, which are sensors with certain functions made by using the Hall effect. At present, such Hall sensors are widely used. The advantages of Hall devices are high reliability, long service life, low noise, no spark interference, uniform and stable rotation speed, and small size.
- Optoelectronic devices and electroacoustic devices:
The structure of the photoelectric triode is the same as that of the ordinary triode, but the working conditions are completely different. Under a given light intensity, the output current of the photodiode is much larger than that of the photodiode. But the main disadvantage is that the photoelectric triode cannot respond quickly to the change of the light intensity, so the photoelectric triode is not suitable for the places where the frequency effect is required to be very fast. Like other optoelectronic devices, the optoelectronic triode can perform various functions in combination with the light source. And in many applications, it can be used to replace photoresistors or photodiodes and can improve work efficiency. Photoelectric triodes can be used in distance measurement, photographic exposure control, smoke detection, timer, mechanical positioning, and other fields. The electroacoustic device restores the amplified sound signal into a sound device. Common ones are speakers, microphones, headphones, etc.
- Surface Mounted Devices:
In recent years, the volume of electronic products has been continuously reduced, but the functions have become increasingly rich, and the circuits have become more and more complex, which requires the miniaturization the circuits. The components used in the circuit should be reduced accordingly, and the leads of the components should be as short as possible or even without leads. As a result, chip resistors, chip capacitors, chip inductors, chip diodes, chip triodes, chip field-effect transistors, chip integrated circuits, chip quartz crystals, etc., to meet the needs of the market.
- Integrated circuit devices:
According to the manufacturing process, integrated circuits can be divided into semiconductor integrated circuits, thin-film integrated circuits, thick film integrated circuits, and hybrid integrated circuits. The most widely used currently is the semiconductor integrated circuit. Depending on the type of active device, such can be further subdivided into bipolar, MOS, and bipolar-MOS ICs. According to the degree of integration, semiconductor integrated circuits can be divided into small-scale, medium-scale, large-scale, and ultra-large-scale integrated circuits.
- Electronic display devices:
The display device is the part of the display, which is divided into the mechanical indicating device and electronic display devices.
- Relays, optocoupler devices:
A relay is an electronic control element with a control system (input loop) and a controlled system (output loop) and is usually used in automatic control circuits. It is an automatic switch that uses a smaller current to control a larger current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit. Photoelectric coupling elements are a group of devices that transmit electrical signals through light as a medium. Their function is to isolate the input circuit and the output circuit at ordinary times and to transmit electrical signals through the isolation layer when needed.
The photoelectric coupling element can transmit signals between two circuits that do not share the ground, even if there is a high voltage between the two circuits, it will not be affected. The input-to-output withstand voltage of commercial optocouplers can reach 10 kV, and the voltage change rate can be as fast as 10 kV/μs. Photoelectric coupling components can be divided into analog and digital, both of which are composed of light emitters and light detectors. The light emitter and light detector are usually integrated into the same package, but there will be no electrical or physical connection between them other than the light beam.