Electronic components are the basic components combined together to make complete electronic products. Understanding the functions, types, structures, and properties of commonly used electronic components is fundamental to understanding electronic technology.
What are Electronic Components?
An electronic component, also called an electronic device, or circuit element, is the basic element in an electronic circuit. It is usually an individual package, with two or more leads or metal contacts to connect it to an electronic device. Electronic components must be connected by circuits to electronic devices where they perform specific functions. One of the common ways to connect electronic components to a device is by soldering it to a printed circuit board.
Electronic components may be individual packages called discrete components. Alternatively, multiple electronic components and circuits may be fabricated on the surface of a semiconductor wafer in a concentrated and miniaturized manner to perform processes of various complexities. These are called integrated circuits.
Component Type:
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.
- Active components are electronic components that have gain or directionality when used relative to passive components. These include semiconductor devices and vacuum tubes.
What are the Common Types of Electronic Components?
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Resistors:
Electronic resistors are often simply referred to as resistors, and are denoted by R in schematic diagrams. They are some of the most commonly 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 electronics current flowing through them. A byproduct of resisters it that they convert the current energy into heat energy.
Resistors are used in almost all electronic products. Resistors are used in electronic circuits to step down voltage, limit current, divide voltages and divide currents, and together with other components, they 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 that allows the flow of 1A of current when a voltage of 1V is applied to the conductor. Larger resistors may be defined in KΩ or MΩ.
There are many types of resistors, and some of the most commonly 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.
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Capacitor:
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 in schematic diagrams by the letter 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.
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Inductors:
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.
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Transformer:
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. 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 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.
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Semiconductor:
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 many types of crystal triodes, which are mainly divided into triodes made of PNP type germanium materials, NPN type germanium materials, PNP type silicon materials, NPN type silicon materials, and compound materials. They are further divided into high-frequency triodes, intermediate frequency triodes, low-frequency triodes, and so on. According to their power rating, they are divided into low-power triodes, medium-power triodes, and high-power triodes.
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Thyristor and field-effect transistor:
The thyristor or Silicon Controlled Rectifier (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 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.
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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, electronic vacuum devices in ultra-high frequency technology, oscilloscope tubes, and picture tubes in display technology, etc., still use the electron tube as mainstream.
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Piezoelectric devices and Hall devices:
The quartz crystal oscillator is made by using the piezoelectric effect characteristics of the quartz crystal. 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 sensors that using the Hall effect to detect current flow. The advantages of Hall devices are their high reliability, long service life, low noise, no spark interference, uniform and stable rotation speed, and small size.
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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 photoelectric triode is much larger than that of the photodiode. 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. 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 uses are in speakers, microphones, headphones, etc.
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Surface Mounted Devices:
In recent years, the size of electronic products has been continuously reduced, while their functions have become increasingly rich. Circuits have become more and more complex, requiring the miniaturization of the circuits. The components used in the circuits 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, are being improved to meet the needs of the market.
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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.
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Electronic display devices:
The display device is a device for presentation of information. They can be either mechanical indicating devices such as a meter with indicator needles, or electronic display devices with some kind of display screen.
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Relays, optocoupler devices:
A relay is an electronic control element with a control system (input loop) and a controlled system (output loop) that is used in automatic control circuits. It uses a smaller current to control a larger current. It is used for processes requiring automatic adjustment and safety protection. Photoelectric coupling elements are devices that transmit electrical signals through light as a medium. Their function is to transmit electrical signals from an input circuit to an output circuit.
The photoelectric coupling element can transmit signals between two circuits that do not share the ground. 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.
