What are the top ten commonly used electronic components?

What are the commonly used electronic components? How many do you know? For engineers working in the electronics industry, electronic components need to be touched and used every day, but in fact many engineers may not understand them. Here are the top ten electronic components commonly used by engineers, as well as related basic concepts and knowledge, and review them with everyone.

1. Resistance

As a worker in the electronics industry, everyone knows about resistors. Its importance is beyond doubt. People say that "resistance is the most commonly used component in all electronic circuits." Resistor is called a resistive substance because of the hindering effect of substances on current flow. Resistance will cause changes in the electron flow. The smaller the resistance, the greater the electron flow, and vice versa. A substance that has no resistance or very little resistance is called an electrical conductor, or conductor for short. Substances that cannot form electrical current transmission are called electrical insulators, or insulators for short.

In physics, resistance is used to represent the resistance of a conductor to current flow. The greater the resistance of a conductor, the greater the resistance of the conductor to current flow. Different conductors generally have different resistances. Resistance is a characteristic of the conductor itself. Resistive elements are energy-consuming elements that hinder current flow. The resistance value of a resistive element is generally related to temperature. The physical quantity that measures the effect of resistance on temperature is the temperature coefficient, which is defined as the percentage change in resistance value for every 1°C increase in temperature.

The resistance is represented by "R" plus a number in the circuit. For example: R1 represents the resistor numbered 1. The main functions of resistors in circuits are current shunting, current limiting, voltage dividing, biasing, etc.

2. Capacitor

Capacitance (or capacitance, Capacitance) refers to the amount of charge stored at a given potential difference; it is marked as C, and the international unit is Farad (F). Generally speaking, charges will move under force in an electric field. When there is a medium between conductors, it will hinder the movement of charges and cause charges to accumulate on the conductors; causing the accumulation of charges. The most common example is two parallel pieces of metal. plate. It is also the common name of capacitor.

1. Capacitors are generally represented by "C" plus a number in the circuit (for example, C13 represents the capacitor numbered 13). A capacitor is a component composed of two metal films in close proximity and separated by an insulating material. The main characteristic of capacitors is to block DC and AC. The size of the capacitor represents the amount of electrical energy that can be stored. The hindering effect of the capacitor on the AC signal is called capacitive reactance, which is related to the frequency and capacitance of the AC signal. Capacitive reactance

2. Identification method: The identification method of capacitor is basically the same as that of resistor, which is divided into three types: direct marking method, color marking method and numerical marking method. The basic unit of capacitance is expressed in farads (F), and other units include: millifarads (mF), microfarads (uF), nanofarads (nF), and picofarads (pF).

3. Crystal Diode

Crystal diode is a semiconductor two-terminal device in solid-state electronic devices. The main characteristic of these devices is their nonlinear current-voltage characteristics. Since then, with the development of semiconductor materials and process technology, a variety of crystal diodes with a wide variety of structures and different functions and uses have been developed using different semiconductor materials, doping distributions, and geometric structures. Manufacturing materials include germanium, silicon and compound semiconductors. Crystal diodes can be used to generate, control, receive, transform, amplify signals and perform energy conversion, etc.

Crystal diodes are often represented by "D" plus a number in the circuit. For example, D5 represents the diode numbered 5.

1. Function: The main characteristic of a diode is unidirectional conductivity, that is, under the action of forward voltage, the on-resistance is very small; while under the action of reverse voltage, the on-resistance is extremely large or infinite. Because diodes have the above characteristics, they are often used in cordless phones in circuits such as rectification, isolation, voltage stabilization, polarity protection, coding control, FM modulation and squelch. The crystal diodes used in telephones can be divided according to their functions: rectifier diodes (such as 1N4004), isolation diodes (such as 1N4148), Schottky diodes (such as BAT85), light-emitting diodes, Zener diodes, etc.

2. Identification method: The identification of diodes is very simple. The N pole (negative pole) of low-power diodes is mostly marked with a color circle on the surface of the diode. Some diodes also use special diode symbols to represent the P pole (positive pole) or N pole. (negative pole), there are also symbols marked as "P" and "N" to determine the polarity of the diode. The positive and negative poles of a light-emitting diode can be identified by the length of the pins. The long pin is positive and the short pin is negative.

3. Testing precautions: When using a digital multimeter to measure a diode, connect the red test lead to the anode of the diode and the black test lead to the cathode of the diode. The resistance measured at this time is the forward conduction resistance of the diode, which is different from the pointer type. The connection method of the multimeter's test leads is exactly the opposite.

4. Zener diode

Zener diode (also called Zener diode), this diode is a semiconductor device with high resistance until the critical reverse breakdown voltage. Zener diodes are often represented by "ZD" plus a number in the circuit. For example: ZD5 means Zener diode numbered 5.

1. Voltage stabilization principle of Zener diode: The characteristic of Zener diode is that after breakdown, the voltage at both ends remains basically unchanged. In this way, when the voltage regulator tube is connected to the circuit, if the voltage at each point in the circuit changes due to fluctuations in the power supply voltage or other reasons, the voltage at both ends of the load will remain basically unchanged.

2. Fault characteristics: The faults of the Zener diode are mainly manifested in open circuit, short circuit and unstable voltage value. Among these three types of faults, the former shows an increase in the power supply voltage; the latter two types of faults show that the power supply voltage becomes low to zero volts or the output is unstable.

5. Inductance

Inductance: When a current passes through a coil, a magnetic field is induced in the coil, and the induced magnetic field generates an induced current to resist the current passing through the coil. We call this interaction between the current and the coil the electrical inductance, that is, the inductance, and its unit is "Henry" (H). This property can also be used to make inductive components.

Inductors are often represented by "L" plus a number in the circuit. For example, L6 represents the inductor numbered 6. The inductor coil is made by winding an insulated wire a certain number of turns around an insulated frame. DC can pass through the coil. The DC resistance is the resistance of the wire itself, and the voltage drop is very small. When the AC signal passes through the coil, a self-induced electromotive force will be generated at both ends of the coil. The direction of the self-induced electromotive force is opposite to the direction of the applied voltage, hindering the communication. Pass, so the characteristic of the inductor is to pass DC and resist AC. The higher the frequency, the greater the coil impedance. The inductor can form an oscillation circuit with the capacitor in the circuit. Inductors generally have direct marking methods and color marking methods. The color marking method is similar to resistors. For example: brown, black, gold and gold represent an inductor of 1uH (error 5%).

The basic unit of inductance is: Henry (H). The conversion unit is: 1H=103mH=106uH.

6. Varactor diode

Varactor Diodes are also called "variable reactance diodes". It is a diode made by utilizing the dependence and principle of PN junction capacitance (barrier capacitance) and its reverse bias voltage Vr.

The varactor diode is a special diode specially designed based on the principle that the junction capacitance of the "PN junction" inside an ordinary diode can change with the change of the applied reverse voltage. Varactors are mainly used in cordless phones in the high-frequency modulation circuit of mobile phones or landlines to modulate low-frequency signals to high-frequency signals and then transmit them. In the working state, the modulation voltage of the varactor diode is generally applied to the negative electrode, so that the internal junction capacitance of the varactor diode changes with the change of the modulation voltage.

When the varactor diode fails, the main manifestations are leakage or performance deterioration: (1) When leakage occurs, the high-frequency modulation circuit will not work or the modulation performance will deteriorate. (2) When the varactor performance deteriorates, the operation of the high-frequency modulation circuit is unstable, causing the modulated high-frequency signal to be sent to the other party and then distorted after being received by the other party. When one of the above situations occurs, the varactor diode of the same model should be replaced.

7. Transistor

The transistor is one of the basic components of semiconductors. It has the function of current amplification and is the core component of electronic circuits. The transistor is made of two PN junctions that are very close to each other on a semiconductor substrate. The two PN junctions divide the main semiconductor into three parts. The middle part is the base area, and the two sides are the emitter area and the collector area. The arrangement is PNP and NPN.

Transistors are often represented by "Q" plus a number in the circuit, for example: Q17 represents the transistor numbered 17.

1. Features: A transistor (transistor for short) is a special device that contains two PN junctions inside and has amplification capabilities. It is divided into two types: NPN type and PNP type. These two types of transistors can complement each other in terms of working characteristics. The so-called pair of transistors in the OTL circuit is a pair of PNP type and NPN type. PNP transistors commonly used in telephones include: A92, 9015 and other models; NPN transistors include: A42, 9014, 9018, 9013, 9012 and other models.

2. Transistors are mainly used for amplification in amplifier circuits. There are three connection methods in common circuits.

8. Field effect tube

Field Effect Transistor (Field Effect Transistor abbreviation (FET)) is referred to as field effect transistor. The majority carriers participate in conduction, also known as unipolar transistors. It is a voltage-controlled semiconductor device. It has the advantages of high input resistance, low noise, low power consumption, large dynamic range, easy integration, no secondary breakdown phenomenon, and wide safe operating area. It has become a strong competitor of bipolar transistors and power transistors.

1. Field effect transistors have the advantages of high input impedance and low noise, and are therefore widely used in various electronic devices. In particular, using field effect tubes as the input stage of the entire electronic device can achieve performance that is difficult to achieve with ordinary transistors.

2. Field effect transistors are divided into two categories: junction type and insulated gate type, and their control principles are the same.

3. Comparison between field effect transistors and transistors

(1) Field effect transistors are voltage control components, while transistors are current control components. When only a small amount of current is allowed to be taken from the signal source, a field effect transistor should be used; when the signal voltage is low and a large amount of current is allowed to be taken from the signal source, a transistor should be used.

(2) Field effect transistors use majority carriers to conduct electricity, so they are called unipolar devices, while transistors have both majority carriers and minority carriers to conduct electricity. It is called a bipolar device.

(3) The source and drain of some field effect transistors can be used interchangeably, and the gate voltage can be positive or negative, which is more flexible than transistors.

(4) Field effect transistors can work under very low current and very low voltage conditions, and its manufacturing process can easily integrate many field effect transistors on a silicon wafer. Therefore, field effect transistors are widely used in large-scale integrated circuits. has been widely used.

9. Sensor

A sensor is a physical device or biological organ that can detect and feel external signals, physical conditions (such as light, heat, humidity) or chemical composition (such as smoke), and transmit the detected information to other devices or organs.

The national standard GB7665-87 defines a sensor as: "a device or device that can sense the specified measured object and convert it into a usable signal according to certain rules. It is usually composed of a sensitive element and a conversion element." A sensor is a detection device that can sense the measured information and convert the detected information into electrical signals or other required forms of information output according to certain rules to meet the needs of information transmission, processing, storage, Display, recording and control requirements. It is the primary link to realize automatic detection and automatic control.

"Sensor" is defined in the New Webster Dictionary as:

"Accepts power from one system and delivers it, usually in another form, to a device in a second system." According to this definition, the function of a sensor is to convert one type of energy into another form of energy, so many scholars also use "Transducer" to refer to "Sensor".

10. Transformer

Transformer is a device that uses the principle of electromagnetic induction to change AC voltage. Its main components are primary coil, secondary coil and iron core (magnetic core). In electrical equipment and wireless circuits, it is often used to increase and decrease voltage, match impedance, safety isolation, etc.

In a generator, whether the coil moves through a magnetic field or the magnetic field moves through a fixed coil, an electric potential can be induced in the coil. In both cases, the value of the magnetic flux remains unchanged, but the number of magnetic fluxes intersecting the coil does. Change, this is the principle of mutual induction. A transformer is a device that uses electromagnetic mutual induction to transform voltage, current and impedance. The main functions of the transformer are: voltage conversion; current conversion, impedance conversion; isolation; voltage stabilization (magnetic saturation transformer), etc. The above are commonly used electronic components, I hope it can help you.