Engaged in the electronic industry, there is an indescribable feeling for all kinds of electronic components. For engineers engaged in the electronic industry, electronic components are like People's Daily imports of rice, which need to be contacted every day and used every day, but in fact, many engineers may not understand the door. Here is a list of the electronic industry in the engineering door commonly used ten electronic components, and related basic concepts and knowledge, and we review again.
Star 1: Resistance
As a worker in the electronic industry, resistance is known to everyone. Its importance is beyond question. It is said that "resistance is the most used element in all electronic circuits."
Resistance, because of the resistance of a substance to an electric current, is called the substance that resists its action. Resistance will result in a change in the flux of electrons; the smaller the resistance, the greater the flux, and vice versa. Substances with little or no resistance are called electrical conductors, or conductors for short. Substances that cannot form current transmission are called electrical insulators, or insulators for short.
In physics, Resistance is used to indicate the magnitude of the conductor's Resistance to the current. The greater the resistance of the conductor, the greater the resistance of the conductor to the current. Resistance is usually different for different conductors, and resistance is a characteristic of the conductor itself. The resistance element is the energy dissipation element which presents the hindering effect to the current.
The resistance value of the resistance element is generally related to temperature. The physical quantity measuring the resistance affected by temperature is the temperature coefficient, which is defined as the percentage of the change of resistance value when the temperature increases by 1℃.
Resistors are denoted by "R" plus a number in the circuit. For example, R1 indicates the resistance numbered 1. The main role of resistance in the circuit is shunt, current limiting, voltage divider, bias, etc.
1. Parameter identification: the unit of resistance is ohm (ω), the unit of multiplier is thousand ohm (K ω), megohm (M ω), etc. The conversion method is: 1 megadohm =1000 kilohm =1000000 ohms. There are three methods of parameter labeling, namely, direct labeling, color labeling and number labeling. A, number marking method is mainly used for small volume circuit such as patch, such as: 472 means 47×100 ω (i.e. 4.7K); 104 means 100Kb, color ring labeling method is most used, here is an example: four-color ring resistance five-color ring resistance (precision resistance).
2. The color code position and power relation of resistance are shown in the following table: Color Effective digital multiplier allowable deviation (%) Silver /x0.01±10 Gold/X0.1 ±5 Black 0+0/ brown 1x10±1 Red 2x100±2 Orange 3x1000/ yellow 4x10000/ green 5x100000±0.5 Blue 6x1000000±0.2 purple 7x10000000±0 1 Grey 8x100000000/ white 9x1000000000/
Star 2: Capacitance
Capacitance refers to the amount of charge stored at a given potential difference; Let's call it C, and the si unit is farrah. In general, electric charges in an electric field will be forced to move, when there is a medium between the conductors, the charge movement is prevented and the charge accumulates on the conductor; The most common example of this accumulation of charge is when two metal plates are parallel. Also known as capacitor.
1, capacitance in the circuit is generally "C" plus a number (such as C13 for the capacitor numbered 13). Capacitance is a component consisting of two metal films close together and separated by an insulating material. Capacitors are characterized primarily by direct current alternating current. The size of the capacitance is the size of the storage of electric energy, the capacitance of the ac signal is called the resistance, which is related to the frequency and capacitance of the AC signal. Reactance XC=1/2π FC (F indicates the frequency of ac signal, C indicates the capacitance capacity) The commonly used types of capacitance in telephone are electrolytic capacitor, ceramic capacitor, chip capacitor, monolithic capacitor, tantalum capacitor and polyester capacitor. Please visit: POWER Transmission and distribution Equipment network for more information
2. Identification method: The identification method of capacitance is basically the same as that of resistance. There are three kinds of direct marking method, color marking method and number marking method. The basic unit of capacitance is expressed in farad (F). Other units include millimethod (mF), micro method (uF), nano method (nF), and skin method (pF). Among them: 1 farad =103 millimethod =106 micro method =109 nano method =1012 skin method the capacity value of the capacitor with large capacity is directly marked on the capacitor, such as 10uF/16V small capacity of the capacitance of the capacity value in the capacitor with letters or numbers to indicate the letter representation: 1M =1000uF1P2= 1.2pf1n =1000PF Digital representation: Generally, three digits are used to indicate the capacity, with the first two digits representing the significant digit and the third digit being the multiplier. For example, 102 means 10×102PF=1000PF224 means 22×104PF= 0.22UF3, capacitance error table symbol FGJKLM allowable error ±1%±2%±5%±10%±15%±20%, such as: a ceramic capacitor 104J means capacity is 0.1uF, error is ±5%.
Star III: Crystal diode
Crystaldiode (crystaldiode) semiconductor ends in solid state electronics devices. The main characteristic of these devices is their nonlinear current-voltage characteristics. Since then, with the development of semiconductor materials and technology, using different semiconductor materials, doping distribution, geometric structure, developed a variety of crystal diodes with a wide variety of structures, different functions and uses. Manufacturing materials include germanium, silicon and compound semiconductors. Crystal diodes can be used to generate, control, receive, transform, amplify signals and perform energy conversion.
Crystal diode in the circuit commonly used "D" plus a number, such as: D5 for the number of 5 diode.
1, function: the main characteristic of the diode is one-way conductivity, that is, under the action of the forward voltage, the on-resistance is very small; The on-resistance is extremely large or infinite under the effect of the reverse voltage. Because of the above characteristics of diode, it is often used in cordless telephone rectification, isolation, voltage regulation, polarity protection, coding control, frequency modulation and noise static circuits. The crystal diode used in the telephone can be divided into: rectifier diode (such as 1N4004), isolation diode (such as 1N4148), Schottky diode (such as BAT85), light-emitting diode, regulator diode and so on.
2, recognition methods: identification of a diode is very simple, small power diode N pole (cathode), in the diode looks mostly adopts a circular color standard, some diodes also use special symbols to represent a P (positive) or N (cathode), also have use symbols for "P", "N" to determine of polarity of the diode. The positive and negative poles of the light-emitting diode can be identified from the pin length. The long pin is positive and the short pin is negative.
3, test notes: with the digital multimeter to measure the diode, red pen diode positive, black pen diode negative, the measured value of the resistance is the diode of the positive guide resistance value, which is the opposite of the pointer multimeter.
4, commonly used 1 n4000 series diode voltage comparison is as follows: model 1 n40011n40021n40031n40041n40051n40061n4007 501002004006008001000 current voltage (V) (A) 1.
Star four: voltage regulator diode
A zener diode is a semiconductor device with a very high resistance up to the critical reverse breakdown voltage.
Regulator diode in the circuit commonly used "ZD" plus a number, such as: ZD5 for the number of the regulator tube 5.
1, the principle of the regulator diode: the regulator diode is characterized by breakdown, the voltage at both ends of the basic unchanged. In this way, when the regulator tube is connected to the circuit, if the power supply voltage fluctuates, or other reasons caused by voltage changes at each point in the circuit, the voltage at both ends of the load will remain basically unchanged.
2, fault characteristics: the regulator diode fault is mainly shown in open circuit, short circuit and the regulator value is unstable. Of the three faults, the former one shows an increase in the supply voltage; The latter two types of faults are characterized by power supply voltage dropping to zero volts or unstable output. The models and values of common regulator diodes are as follows: Type 1 n47281n47291n47301n47321n47331n47341n47351n47441n47501n47511n4761 voltage value of 3.3 V3.6 V3.9 V4.7 V5.1 V5.6 V6.2 V15V27V30V75V.