What are the resistors functions,parameters and how to identify the resistance of the resistor?
1.Functions
The resistor is referred to as "resistance", and is an electronic component with reduced voltage and current limiting.
The electronic components made by electric current are the most basic and commonly used electronic components in electronic products.
2.The main parameters of the resistor
The main parameters of resistor include nominal resistance and allowable deviation, rated power and temperature coefficient.
The unit is Ohm. There are also thousands of Euclidean and megabytes in common use, and the conversion relationship between them is: 1 Mega ohm =1000 kilo ohm =1000000 ohm.
(1) resistance nominal series and allowable deviation
( 2 ) Resistance temperature coefficient.
The resistance temperature coefficient is used to indicate the relative change of resistance when the working temperature of the resistor is changed. When the working temperature changes, the resistance of the resistor will change accordingly, which is not desirable for the general resistor. The smaller the coefficient is, the higher the resistance is. The resistance temperature shows two kinds, that is, positive coefficient and negative coefficient, according to the material of manufacturing resistance. The former increases with the increase of temperature, and the latter decreases with increasing temperature.
( 3 ) Rated power rating refers to a resistor in a DC or AC circuit, at a certain atmospheric pressure and at a temperature specified in the product standard, maximum allowable power for long-term continuous work. In order to ensure the safe use, the rated power should be 1 ~ 2 times higher than the power it consumes in the circuit.
3.Identify the resistance of the resistor.
Nominal value of the main methods are : direct annotation, color ring, text symbols, digital labeling method.
( 1 ) Direct annotation method is to directly mark the category, nominal resistance and allowable deviation, rated power and other main parameters of the resistor directly on the outer surface of the resistor. It is suitable for bulk resistors, and small size resistors are not used.
( 2 ) The color ring standard method is to mark the parameters of the resistor on the surface of the resistor with a color ring or a color point of different colors. The commonly used methods of color ring annotation are four ring labeling method and five ring annotation method.
