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Recognition and Measurement of Electronic Components

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This video mainly explains the parameters of resistors and the applications of resistors

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Different resistors, resistance values, specifications and other parameters are different,

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we can identify them through the schematic diagram

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R1221 is the position number of the resistor

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1.0K represents the resistance value of the resistor,

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and 5% is the error of the resistance value

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1/32 W represents the power of the resistor,

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01005 represents the specification of the resistor,

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generally refers to the length and width

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In the Android drawing, the identification of the resistor is relatively simple,

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only the position number and the resistance value of the resistor are marked

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Some Android drawing will not mark the resistance value of the resistor,

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Resistors are called differently in different circuits

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In mobile phone mainboards, commonly used resistors can be divided into fuse resistors,

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pull-up resistors, pull-down resistors and thermistors

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The function of the fuse resistor is mainly to protect the components in the circuit from being burned out

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In the power supply and signal lines, fuse resistors are used

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The fuse resistor is connected in the middle of the line,

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and the general resistance is below 10 ohm

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However, the resistance of the fuse resistor on the signal line ranges from 0 ohm to tens of K ohms

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Pull-up resistor

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The function of the pull-up resistor is to pull up the uncertain signal to a high voltage,

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increase the current of the line,

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and allow the signal to be transmitted at a high speed over a long distance

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For example, in the picture, PP1V8_IO is powered through a 4.3k resistor

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After the power supply passes through the resistor,

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it will provide current to the signal line, but the current will be very small

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Identification of pull-up resistors

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In the circuit, when one end of the resistor is connected to the power supply

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and the other end is connected to the signal line,

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this resistor is called a pull-up resistor.

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The pull-up resistors cannot be removed

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After removal, the working voltage of the signal line will be abnormal,

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which will cause restart or failure

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Ok, that's all for this video