Basic knowledge of electronic components

- Jul 06, 2018 -

Resistance


The resistor is represented by a "R" plus a number in the circuit. For example, R1 represents a resistor numbered 1. The main functions of the resistor in the circuit are: shunt, current limit, voltage division, offset, etc.

1. Parameter identification: The unit of resistance is ohm (Ω), and the unit of magnification is: kilo ohm (KΩ), megohm (MΩ) and so on. The conversion method is: 1 megohm = 1000 kohm = 1000000 Euro

There are three kinds of parameter labeling methods for resistance, namely, direct label method, color scale method and number label method.

a. The digital standard method is mainly used for small-sized circuits such as patches, such as: 472 for 47×100Ω (ie 4.7K); 104 for 100K

b. The color circle labeling method is the most used. The examples are as follows:

Four-color ring resistance Five-color ring resistance (precision resistance)

2. The relationship between the color mark position and the magnification of the resistor is shown in the following table:

Color Effective number Magnification Allowable deviation (%)

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 x10000000 ±0.1 Gray / x100000000 / White 9 x1000000000 /


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