Function and identification of IC electronic components, eight common electronic components

Resistance is represented by adding numbers to the circuit using 'R', for example: R1 represents a resistance of 1. The main functions of resistance in the circuit are separation, current limiting, voltage sharing, bias, etc. 1. Parameter identification:

Ohm is a unit of resistance (Ω), with multiple units such as kiloohms (K Ω), megaohms (M Ω), and so on. The calculation method is as follows:

1 megaeuro=1000 thousand euros=100000 euros

There are three methods for marking resistance parameter values, namely direct labeling, color labeling, and numerical labeling. a. The digital scaling method is mainly used for small volume circuits such as chip mounting, such as:

472 indicates 47 * 100 Ω (i.e. 4.7K); 104 also represents 100K

b. The color ring labeling method is the most commonly used, with the following examples:

Four color ring resistor Five color ring resistor (precision resistor)

2. The color code position and multiple correlation of the resistance are shown in the table below:

Allowable error of hue Significant figures multiple (%)

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

Purple 7 x1000000 ± 0.1

Grey 8 x 100000000/

White 9 x 100000000/

（2） Capacitance 1 Capacitors are usually represented by adding numbers to "C" in a circuit (such as C13 for capacitor number 13). A capacitor is a component composed of two layers of metal film tightly attached and separated by an insulating material in the middle. The characteristic of a capacitor is usually that it flows through the circuit directly. The size of a capacitor refers to the size of energy that can be stored, and the obstruction of a capacitor to an AC signal is called capacitive impedance, which is related to the quantity and capacity of the AC signal. Capacitive impedance XC=1/2 π f c (f represents the number of AC signals, C represents capacitance). The common capacitors in the telephone are Electrolytic capacitor, ceramic chip capacitor, chip capacitor, monolith capacitor, tantalum capacitor, polyester capacitor, etc. 2. Identification method: The identification method for capacitors is basically the same as that for resistors, which can be divided into direct labeling method, color labeling method, and numerical labeling method. The basic elements (F) of Faraday capacitors indicate that other companies also have: milliFaraday (mF), microfabric (uF), nanoFaraday (nF), and picosecond (pF). Among them, 1 farad=103m method=106 microf theads=109 nanof theads=1012 picf theads

The volume value of a large capacity capacitor is directly indicated on the capacitor, such as 10 uF/16V

The volume value of a small capacity capacitor is represented by letters or numbers on the capacitor

Letter representation: 1m=10000 uF 1P2=1.2PF 1n=1000PF

Data representation: the volume size is generally represented by three digits, the first two digits represent Significant figures, and the third digit is a multiple. For example, 102 represents 10 * 102PF=1000PF, 224 represents 22 * 104PF=0.22 uF

3. Capacitance Deviation Table

Symbol F G J K L M

Allowable error ± 1% ± 2% ± 5% ± 10% ± 15% ± 20%

For example, a 104J ceramic capacitor represents 0 capacity 1 uF with a deviation of ± 5%. (3) Crystal diode

Crystal diodes are common in circuits. D "Add numbers to indicate, for example, D5 refers to the diode with the number of 5. 1. Efficacy: the key feature of the diode is unidirectional conduction, that is, under the influence of forward voltage, the conductive resistance is very small; but under the influence of reverse voltage, the conductive resistance is large or infinite. Because the diode has the above characteristics, Cordless telephone is commonly used in rectification, protection, voltage stabilization, polarity maintenance, numbering operation, frequency modulation deployment, noise suppression and other circuits. According to efficacy The crystal diodes used can be divided into: rectifier diodes (such as 1N4004), protection diodes (such as 1N4148), Schottky diodes (such as BAT85), light emitting diodes, voltage regulator diodes, etc. 2. Identification method: The identification of diodes is very simple. The N-pole (negative stage) of low-power diodes is mainly marked by the color circle on the diode surface. Some diodes use special markings to describe the P-pole (positive) or N-pole (negative) of the diode, Some symbols are marked with 'P', ' N determines the polarity of the diode. Pins can quickly identify the positive and negative of the LED, with the long pin being positive and the short pin being negative. 3. Inspection precautions: When measuring diodes with a digital multimeter, connect the red lead to the positive stage of the diode and the black lead to the negative stage of the diode. The measured resistance value at this time is the positive guiding resistance value of the diode, which is exactly the opposite of the connection method of the pointer multimeter probe. 4. The common 1N4000 series diodes have the following compressive strength:

Model 1N4001 1N4002 1N4003 1N4004 1N4005 1N4006 1N4007

Compression resistance (V) 50 100 200 400 600 800 1000

The current (A) is all 1

（4） Zener diode

Zener diodes are common in circuits with ZD Add a numerical representation, for example: ZD5 represents a voltage regulator of 5. 1. The voltage regulation principle of a voltage regulator diode: The characteristic of a voltage regulator diode is that after penetration, the voltage at both ends remains basically unchanged. This way, when the voltage regulator is connected to the circuit, if the voltage at each point in the circuit changes due to power current fluctuations or other reasons, the voltage at both ends of the load will remain basically unchanged. 2. Fault characteristics: The fault of the voltage regulator diode is mainly reflected in The guidance, short circuit, and voltage stabilization values are unstable. Among these three faults, the previous fault indicates an increase in power supply current; The last two faults indicate that the power supply current has dropped to zero volts or the output is unstable. The commonly used models and voltage stabilizing values of voltage stabilizing diodes are shown in the table below:

Model 1N4728 1N4729 1N4730 1N4732 1N4733 1N4734 1N4735 1N4744 1N4750 1N4751 1N4761

Stabilized voltage 3.3V 3.6V 3.9V 4.7V 5.1V 5.6V 6.2V 15V 27V 30V 75V

（5） Inductance and inductance are common in circuits Add a numerical representation, for example: L6 represents the inductance of number 6. The inductance coil is made by winding a certain number of turns of insulation wire on the insulation frame. DC can pass through the coil, and the DC resistance is the resistance of the wire itself, with a small voltage drop. When the AC signal is based on the coil, self induced potential will be generated on both sides of the coil. The direction of self induced potential is opposite to the direction of additional voltage, which hinders the foundation of AC. Therefore, the characteristic of inductance is that it passes through DC Resistance for communication. The higher the frequency, the greater the coil impedance. Inductors can form resonant circuits with capacitors in a circuit. Inductance is generally divided into direct labeling method and color labeling method, similar to resistance. For example, brown, black, gold, and gold represent an inductance of 1uH (deviation of 5%). The basic element of inductance is: constant (H) conversion unit: 1H=103mH=106uH. （6） Varactor diode

The varactor diode is a specially designed junction capacitor based on the internal "PN junction" of ordinary diodes, which can change with the change of reverse voltage. The varactor diode is mainly used in the high-frequency allocation circuit of mobile phones or landlines in Cordless telephone to allocate low-frequency signals to high-frequency signals and send them out. In operation, the distribution voltage of the variable container diode generally increases to a negative level, causing the internal junction capacitance product of the variable container diode to change with the change of the distribution voltage. The varactor diode has malfunctioned, specifically manifested as power failure or characteristic degradation:

(1) When the power supply occurs, the high-frequency deployment circuit will not work or the deployment characteristics will decrease. (2) When the characteristics of the variable container decrease, the operation of the high-frequency deployment power supply is unstable, causing the deployed high-frequency signal to be sent to the other party and received by the other party, resulting in frame loss. In one of the above situations, the same model of variable container diode should be replaced. (7) Crystal transistor

Crystal transistor is very common in circuits, with the addition of numerical representation. For example, Q17 indicates that the transistor number is 17. 1. Features: Crystal transistor (hereinafter referred to as transistor) It is a unique device that contains two PN junctions internally and has amplification capability. It is divided into two types: NPN type and PNP type. These two types of transistors can complement each other in terms of operating characteristics. The so-called pair transistor in OTL circuits is a matching application of PNP and NPN types. PNP transistor is commonly used in telephones: A92, 9015 models; NPN type transistors are available in models A42, 9014, 9018, 9013, 9012, etc. 2. Crystal triodes are mainly used for amplifying circuits, and there are three connection methods in general circuits. For the convenience of comparison, the characteristics of the three types of transistor connection circuits are listed in the following figure for your reference.

(8) The Field Effect of Transistor Amplifiers

1. Field effect transistors are widely used in various electronic products due to their strong input impedance and low noise. Especially when using field-effect transistors as the input level for the entire electronic device, it is generally difficult for transistors to achieve performance. 2. Field-effect transistor are divided into two types: junction type and insulated gate type, and their control principles are the same.

3. Comparison between Field-effect transistor and transistor

(1) Field-effect transistor is a voltage control element and transistor is a current control element. Field-effect transistor shall be selected when less current can only be obtained from the signal source; However, in cases where the signal voltage is low and more current is allowed to be obtained from the signal source, transistors should be selected. (2) Field-effect transistor uses most carriers to conduct electricity, so it is called monopole device, while transistor uses most carriers and a few carriers to conduct electricity. It is called a bipolar device. (3) The source and drain of some Field-effect transistor can be used interchangeably, and the gate voltage can also be positive or negative, which is more flexible than transistors. (4) The field-effect transistor can work under very low current and pressure, and its processing process can easily integrate many field-effect transistors into silicon chips, so field-effect transistors have been widely used in large integrated circuits.

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