Identification of Fixed Resistors
1. Representation of ordinary fixed resistors
( 1 ) Straight label direct method is to use Arabic numerals and unit symbols in resistors the nominal resistance is directly marked on the surface, and the allowable deviation is expressed directly in percentage.
( 2 ) The method of literal notation is a combination of Arabic numerals and literal symbols to represent nominal resistance. The permissible deviation is represented by a literal symbol , and the number in front of the symbol represents the integer resistance, followed by the first decimal value and the second bit decimal resistance.
( 3 )The color ring method is to mark the nominal resistance and the allowable deviation on the surface of the resistor with different colors of bands or points.
At present, the color ring resistance is widely used in electronic products, and the advantage is that in the process of assembly, debugging and repair, you can see the color ring at any angle without moving the components , readout resistance, easy to use. Ordinary resistor with four color ring, precision resistor with five color ring.
Attention points of color ring method:
1 ) Remember the number of each color represented by the first and second ring. The memory method is as follows : brown = 1 red = 2 orange = 3 yellow = 4 green = 5 blue = 6 purple = 7 ash = 8 white = 9 black = 0
2 ) Bearing in mind the range of resistance represented by the third ring color of the fourth ring resistor and the fourth ring color of the ring resistor, the memory method is : golden : a few European black : dozens of European brown : hundreds of several European red : a few thousand European orange : dozens of thousands of European yellow : several hundred a few thousands of European green : a few megohm blue : dozens of megohm from the order of magnitude, on the whole, they can be divided into three grades, that is : gold, black and brown are ohmic; red is a thousand European level, orange, yellow is ten thousand European level; green is the megohm level; blue is ten megohm.
3 ) When the third ring of the second ring and the ring resistor of the fourth ring resistor is black, the color of the latter ring represents an integer, that is, a few, dozens, hundreds of thousands of euros, etc, which is the special case of reading, we should pay attention to. For example, the third ring in the Fourth Ring is red, and its resistance is the whole thousands of Europe.
4 ) Remember the allowable deviation represented by the last ring color, that is, 5 % gold; silver is 10 %; colorless is 20 %, brown is 1 %.
The following examples are as follows:
Example 1: when the four chromatic rings are in turn yellow, orange, red, and gold, because the third ring is red and the range of the resistance is several thousand of ohms . The number of "4" and "3" representing the yellow and orange two colors respectively is the reading number of 4.3kilo-ohm. The fourth ring is the silver indication that the permissible deviation is 10%.
Example 2: when the five color rings are in turn brown, green, black, orange, and golden, because the fourth ring is orange, the third ring is black and the value should be a few thousand of ohms. The number of brown represents "1", green is "5", and the reading number is 150kilo-ohm. The fifth ring is golden, and its allowable deviation is positive and negative 5%.