Ten common electronic components that electronic engineers love

/ 2018/7/11 15:38:40 / News

In the electronics industry, there is no emotion for all kinds of electronic components. For engineers engaged in the electronic industry, electronic components are like the daily food, which needs to be touched every day and need to be used every day. Here is a list of ten electronic components commonly used by engineering teachers in the electronics industry, named "ten common popular electronic components ", hoping to make more reference and study.

Popular component one: resistor

As a worker in the electronics industry, resistor is unknown. The importance of it is beyond doubt. People say that resistance is the most used component in all electronic circuits.


Resistor, dueing to the impediment of the substance to the electric current, is called the resistance substance under this action. Resistor will lead to changes in the amount of electronic flow, the smaller the resistance, the greater the amount of electronic flow, and vice versa. A substance with very little resistance or resistance is called an electric conductor, or a conductor. The substance that can not form the current transmission is called an electrical insulator, or an insulator.

In physics, the resistance is used to indicate the magnitude of the impediment of the conductor to the current. The greater the resistance of a conductor, the greater the impediment of the conductor to the current. Different conductors have different resistances. Resistance is a characteristic of the conductor itself. Resistive elements are energy dissipation elements that impede current.

The resistance value of the resistance element is generally related to the temperature. The physical amount of the resistance affected by the temperature is the temperature coefficient, which is defined as the percentage of the change of the resistance value when the temperature rises at 1 degrees centigrade.

The resistor is represented by "R" plus the number in the circuit, for example, R1 indicates a resistance of 1. The main functions of resistance in the circuit are shunting, current limiting, partial voltage, bias and so on.

1. Parameter identification: the unit of resistance is Ohm (omega), and the rate units are: 1000 ohm (K Ohm), mega (M Ohm) and so on. The conversion method is: 1 Mega =1000, 1000 ohm =1000000 European resistor, there are 3 ways to mark the parameters, that is, direct mark method, color mark method and number mark method. A and number method are mainly used for small volume circuits such as patches, such as 472 for 47 x 100 omega (4.7K), and 104 indicating that 100Kb and color ring tagging are the most used, for example, four color ring resistance five color ring resistors (precision resistance).

2. The relationship between the color standard and the ratio of the resistance is shown in the following table: the color effective number ratio allowed deviation (%) the silver / x0.01 + 10 gold / x0.1 + 5 black 0 +0 / Brown 1 X10 + 1 red 2 X100 + 2 Orange 3 X1000 / yellow 4 x10000 / Green 5 x100000 + 0.5 Blue 6 x1000000 + 0.2 violet x10000000 00000000 / white 9 x1000000000 /.

Popular components two: capacitor

 Capacitance or capacitance, refers to the amount of charge stored under a given potential difference; it is recorded as C, and the international unit is Fala (F). In general, the charge is moved in an electric field. When a conductor has a medium, it prevents the charge from moving and accumulates the charge on the conductor; the most common example is the two parallel metal plates.


1. capacitor in the circuit is usually expressed in terms of "C" plus numbers (for example, C13 indicates capacitance of 13). Capacitance is composed of two metal films, which are separated by insulating materials in the middle. The main characteristics of the capacitance are the direct circulation and communication. The size of capacitive capacity means the size of the energy that can be stored. The impeding effect of capacitance on AC signals is called reactance, which is related to the frequency and capacitance of the AC signals. Resistance to XC=1/2 PI F C (F for the frequency of AC signals, C for capacitance capacity) the types of capacitors commonly used in the telephone are electrolytic capacitors, ceramic capacitors, patch capacitors, single stone capacitors, tantalum capacitors and polyester capacitors.

2. the identification method: capacitance recognition method and resistance identification method is basically the same, divided into direct mark method, color mark method and number mark method 3 kinds. The basic unit of capacitance is represented by Fala (F). Other units are: mF, uF, nF and pF. Among them: 1 Fala =103 MS =106 micromethod =109 Nana method =1012 leather capacity large capacity capacity value on capacitance directly marked on capacitance, such as the capacity of small capacity of 10 uF/16V capacity value on capacitance with alphabetic notation or numeric expression on capacitance: 1m=1000 uF 1P2=1.2PF 1n=1000PF digital table method: generally using three digit numbers to express capacity The first two digits represent a valid number, and the third digit is a multiplying rate. For example, 102 indicates that 10 x 102PF=1000PF 224 represents 22 x 104PF=0.22 uF3, capacitance capacity error meter F G J K L M allowable error + 1% + 2% + 5% + 15% + 20% such as: a ceramic capacitance is 104J capacity of 0.1 uF, error is + 5%.

Popular components three: crystal diode

Crystal diode is a semiconductor devices at both ends of solid-state electronic devices. The main features of these devices are nonlinear current voltage characteristics. With the development of semiconductor materials and technology, various semiconductor materials, doping distribution and geometric structure have been developed, and many kinds of crystal diodes with various kinds of structure and different functional applications have been developed. The manufacturing materials are germanium, silicon and compound semiconductors. Crystal diodes can be used to generate, control, receive, transform, amplify signals and carry out energy conversion.

crystal diode

The crystal diode is commonly used in the circuit as "D" plus numeric representation, for example, D5 means diode with numbered 5.

1. function: the main characteristic of the diode is the unidirectional conductivity, that is, under the action of the forward voltage, the conduction resistance is very small, and the resistance is great or infinity under the action of the reverse voltage. Because of the characteristics of the diode, the cordless telephone often uses it in rectifying, isolating, stabilizing, polarity protection, coding control, FM modulation and static noise. The crystal diodes used in the telephone can be divided into rectifying diodes (such as 1N4004), isolated diodes (such as 1N4148), Schottky diodes (such as BAT85), light emitting diodes, and voltage regulated diodes.

2. identification method: the identification of the diode is very simple, the N pole (negative) of the small power diode, most of the diode appearance uses a color ring mark, some diodes also use the diode special symbols to express the P polar (positive) or the N pole (negative), and also use the symbol standard to determine the diode pole "P", "N" to determine the diode pole. Sex. The positive and negative poles of light emitting diodes can be identified from the length of pins. The long feet are positive and the short feet are negative.

3. test attention: when using digital multimeter to test the diode, the red pen connects the diode to the cathode, and the black pencil leads the negative electrode. At this time the measured resistance is the forward conduction blocking value of the diode, which is the opposite to the pointer type multimeter.

4.  the voltage resistance of the 1N4000 series diode is compared as follows: the model 1N40011N40021N4003 1N4004 1N40051N40061N4007 pressure (V) 50100200400600800 1000 current (A) is 1.

Popular components four: Voltage regulator diode

Voltage regulator diode, is also called a zener diode, which is a semiconductor device with high resistance until the critical reverse breakdown voltage is reached.

The constant voltage diode is commonly used in the circuit as "ZD" plus numerals, for example, ZD5 means a regulator tube with a serial number of 5.

Voltage regulator diode

1.  the voltage stabilizing principle of voltage stabilizing diode: the characteristic of the diode is that after breakdown, the voltage at both ends remains basically unchanged. In this way, when the voltage regulator is connected to the circuit, the voltage at both ends of the load will remain unchanged if the voltage fluctuates in the power supply or causes the change of the voltage of each point in the circuit.

1. fault characteristics: voltage diode fault is mainly manifested in open circuit, short circuit and stable value instability. In these 3 faults, the former fault shows the power supply voltage rising, and the latter 2 faults are the power supply voltage drop to zero volt or output instability. 1N47281N4729 1N4730 1N4732 1N4733 1N4734 1N4735 1N4744 1N4750 1N4751 1N4761 1N4744 1N4750 1N4751 1N4761 stabilized voltage value 3.3V 3.6V.

Popular components five: Inductor

Inductor: when the coil passes through the current, a magnetic induction is formed in the coil, and the induced magnetic field induces an induced current to resist the current passing through the coil. We call the interaction between the current and the coil electrical inductance, that is, inductance, the unit is "Henry" (H). It is also possible to make use of this property to make inductors.


Inductors are commonly used in the circuit as "L" plus numbers, such as: L6 means inductance with a number of 6. The inductance coil is made of insulated wires on the insulated skeleton around a certain number of turns. DC can pass through the coil, the DC resistance is the resistance of the wire itself, the pressure drop is very small; when the AC signal passes through the coil, the two ends of the coil will produce the self inductance electromotive force. The direction of the self inductance of the EMF is opposite to the applied voltage, which hinders the passing of the communication, so the characteristic of the inductor is through DC resistance communication, the higher the frequency, The greater the impedance of the coil. Inductance in the circuit can be composed of capacitors and oscillating circuits. The inductors usually have direct marking method and color mark method, and the color mark method is similar to the resistance. For example, brown, black, gold and gold represent the inductance of 1uH (error 5%).

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

Popular components six: Varactor Diodes

The varactor diode is also called a "variable reactance diode". It is a diode made up of PN junction capacitance (barrier capacitance) and its reverse bias voltage Vr, and its structure is shown in the right picture.

Varactor Diodes

Tube varactor diode is a special diode designed according to the principle of "PN junction" junction capacitance in the ordinary diode, which changes with the change of the applied reverse voltage. In the cordless telephone, the varactor diode is mainly used in the high frequency modulation circuit of the mobile phone or the seat machine to modulate the low frequency signal to the high frequency signal and send it out. In the working state, the varactor modulation voltage is generally added to the negative pole, so that the capacitance of the internal capacitance of the varactor varies with the modulation voltage. The main performance of the varactor diode is leakage or poor performance. (1) when the leakage occurs, the high frequency modulation circuit will not work or the modulation performance will be worse. (2) when the varactor performance is bad, the work of the high frequency modulation circuit is unstable, so that the modulated high-frequency signal is sent to the other side and distorted after receiving the receiver. In the event of such a situation, the same type of varactor diode should be replaced.

Popular components seven: transistor

Transistor is one of the basic components of semiconductor. It has the function of current amplification, and is the core component of electronic circuit. The triode is made of two very close PN junctions on a semiconductor substrate, and the two PN junctions divide the positive block semiconductor into three parts, the middle part is the base area, and the two sides are the emission and the collector areas, and the arrangement has two kinds of PNP and NPN.


Crystal transistors are commonly used in the circuit as "Q" plus numbers. For example, Q17 is a transistor with a number of 17.

1.characteristics: transistor triode is a special device with 2 PN junction and amplification capability. It is divided into two types of NPN type and PNP type. The two types of triode can make up for each other from the working characteristics. The so-called OTL circuit is used by the PNP and NPN type. The PNP type transistors commonly used in telephone are: A92, 9015 and so on; the NPN type transistors are: A42, 9014, 9018, 9013, 9012 and so on.

2. the transistor is mainly used for amplification in the amplifying circuit, and there are three ways to connect them in common circuits. For the sake of comparison, the characteristics of the three kinds of transistors of transistors are listed in the table below for your reference. Name common emitter circuit co collector circuit (emitter output) common base circuit input impedance (hundreds of Europe to thousands of Europe) large (several hundred Europe to tens of Europe) small (several Europe to tens of Europe) output impedance (thousands of Europe to tens of thousands of Europe) small (several Europe to tens of Europe) large (a few tens of thousands of Europe to hundreds of thousands of Europe) voltage discharge Large magnification (less than 1 and close to 1) large current magnification (dozens) large (TENS) large (TENS) small (less than 1 and close to 1) power magnification large (about 30~40 dB) small (about 10 decibels) (about 10 decibels) (about 15~20 decibels) frequency characteristics high frequency difference in the application of multistage amplifier intermediate stage, low frequency amplification The input stage, output stage, or impedance matching are high-frequency or broadband circuits and constant current source circuits.

Popular components eight: Field Effect Transistor(FET)

The field effect transistor (FET) is referred to as the field effect tube. The majority of carriers participate in conduction, also known as unipolar transistors. It belongs to the voltage controlled semiconductor device. With the advantages of high input resistance (108~109 omega), low noise, low power consumption, large dynamic range, easy integration, no two breakdown and wide safety area, it has become a powerful competitor for bipolar transistors and power transistors.

Field Effect Transistor(FET)

1. FET has many advantages such as high input impedance and low noise, so it is also widely used in various electronic devices. Especially using field effect transistor as the input stage of the whole electronic equipment, it is difficult to achieve the performance of general transistors.

2. FET is divided into two main types: junction type and insulated gate type. The control principle is the same. Figure 1-1-1 is a symbol for two models:

3. Comparison of field effect transistors and transistors

(1) the field effect transistor is a voltage control element, and a transistor is a current control element. The field effect tube should be selected when only a few current from the signal source is allowed, and transistors should be selected under the condition that the signal voltage is low and the signal source is allowed to take more current.

(2) the field effect tube is used most of the carrier conduction, so it is called a unipolar device, and the transistor has a majority carrier and also uses a few carrier conduction. It is called a bipolar device.

(3) the source and drain of some FET can be used interchangeably, gate voltage can be positive and negative, and the flexibility is better than that of transistors.

(4) the field effect tube can work under the condition of very small current and very low voltage, and its manufacturing process can easily integrate a lot of field effect tubes on a piece of silicon chip, so the field effect tube has been widely used in the large-scale integrated circuit.

Popular components nine: sensor

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

The national standard GB7665-87 is defined under the sensor as "a device or device that can feel a specified measured piece and convert it into a available signal in accordance with a certain rule, usually composed of sensitive elements and conversion elements." The sensor is a kind of detection device that can feel the information measured, and can transform the detected information into the information output of the electrical signal or other required forms according to a certain rule, so as to meet the requirements of the transmission, processing, storage, display, recording and control of information. It is the first step to achieve automatic detection and automatic control.


The "sensor" is defined in the new weir dictionary as "a device that receives power from one system and usually sends power to second systems in another form."

According to this definition, the function of the sensor is to convert one kind of energy into another form of energy, so many scholars use "transducer" as "transducer".

Popular components ten: transformer

A transformer (Transformer) is a device that uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil and the core (core). In electrical equipment and wireless circuits, it is often used for lifting voltage, matching impedance, safety isolation and so on. In the generator, whether the coil motion passes through a magnetic field or a magnetic field through a fixed coil, the induction potential can be induced in an on-line loop. In these two cases, the magnetic flux values are all the same, but the flux number of the coils intersecting the chain is changed, which is the principle of mutual inductance.


Transformer is a device that uses electromagnetic mutual inductance to transform voltage, current and impedance. The main functions of transformer are: voltage conversion, current conversion, impedance conversion, isolation, voltage stabilizing (magnetic saturation transformer) and so on.

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