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Anonymous users2024-02-07Tip 1: Find the color rings that mark the error first, so as to arrange the color ring order. The most commonly used color to indicate resistance error is:
Gold, silver, brown, especially gold rings and silver rings, are generally rarely used as the first ring of the resistance color ring, so as long as there are gold rings and silver rings on the resistor, it can be basically determined that this is the last link of the color ring resistance.
Tip 2: Determine if the brown ring is a sign of error. Brown rings are often used as both error loops and significant number loops, and often appear in both the first and last rings, making it difficult to identify who is the first ring.
In practice, it can be judged by the interval between the color rings: for example, for a resistor with five color rings, the interval between the fifth and fourth rings is wider than the interval between the first and second rings, from which the order of the color rings can be determined.
Tip 3: In cases where the color ring spacing alone cannot determine the color ring order, it can also be determined by using the production sequence value of the resistor. For example, there is a resistor's color ring reading order:
Brown, black, black, yellow, brown, its value is: 100 104 = 1m The error is 1, which belongs to the normal resistance series value, if it is read in reverse order: brown, yellow, black, black, brown, its value is 140 100 = 140, and the error is 1.
Obviously, the values of the resistors read out according to the latter order are not available in the production series of resistors, so the order of the latter color ring is incorrect. Resistors are generally divided into materials such as: carbon film resistors, metal film resistors, cement resistors, wire resistors, etc.
The average household appliance uses more carbon film resistors because of its low cost. The accuracy of the metal film resistor is higher, and it is used in equipment with high requirements. Cement resistance and line resistance are able to withstand relatively high power, and the accuracy of line resistance is also relatively high, which is commonly used in demanding measuring instruments.
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Anonymous users2024-02-06The resistance value standard method of resistor usually has the color ring method and the number method.
1. Color ring method.
The so-called color ring method uses different color scales to represent the resistance parameters. There are 4 color rings and 5 color rings, and the meaning of each color ring is as follows.
2. Digital law.
Because the resistance in the mobile phone circuit is generally relatively small, it is rarely marked with the resistance value, and even if there is, the digital method is generally used, namely: 101 - represents 10 * 10 1 that is, 100 ohm resistance; The resistance value of the resistor element is generally related to the temperature, material, length, and cross-sectional area, the color ring resistance is common four-ring resistance and five-ring resistance, the first and second rings of the four-ring resistance represent the number, the third ring represents a few zeros, and the fourth ring represents the error, silver 10%, gold 5%. The unit of resistance is ohms.
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Anonymous users2024-02-05The resistance value is the magnitude of the conductor's resistance to the current. The greater the resistance of a conductor, the greater the resistance of the conductor to the current. Different conductors, the resistance is generally different, and resistance is a property of the conductor itself.
The resistance of a conductor is usually represented by the letter r, and the unit of resistance is ohm, referred to as ohm, and the symbol is .
In the electrical schematic diagram, for the sake of simplicity, the " " in the resistance value is generally omitted, and the resistance value below 1000 ohms is directly represented by numbers; If the resistance value is more than 1,000 ohms, it is denoted by "k"; Megaohms and more are denoted by "m".
Influencing factors: 1. Length: When the material and cross-sectional area are the same, the longer the length of the conductor, the greater the resistance.
2. Cross-sectional area: When the material and length are the same, the smaller the cross-sectional area of the conductor, the greater the resistance.
3. Material: When the length and cross-sectional area are the same, the conductor resistance of different materials is different.
4. Temperature: For most conductors, the higher the temperature, the greater the resistance, such as metal; For a few conductors, the higher the temperature, the lower the resistance, such as carbon.
Resistance is a property of the conductor itself, so the resistance of the conductor has nothing to do with factors such as whether the conductor is connected to the circuit, whether there is current in the conductor, and the magnitude of the current. The resistivity of a superconductor is zero, so the resistance of a superconductor is zero.
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Anonymous users2024-02-04Resistance is the dampening effect of a conductor on an electric current. A resistive element is an energy-dissipating element that hinders the current current. The magnitude of the resistance is expressed in terms of the value of the resistance. The resistance value is the magnitude of the conductor's resistance to the current. The unit is ohms ( ).
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Anonymous users2024-02-03Looking at the resistance value of the resistor through the color wheel, the readings are Brown 1, Red 2, Orange 3, Yellow 4, Green 5, Blue 6, Violet 7, Gray 8, White 9, Black 0.
Gold and silver are errors, (errors can not be remembered), the first and second rings of ordinary resistors can be read directly, and the third ring is a multiple, for example: red, red, yellow, gold or silver, the resistance is 220k. Former Qing Pao Xiang.
Keeping in mind the range of resistance represented by the color of the third ring is the key to quick understanding. Specifically: Gold:
What time is it Black: A few dozen before a few Brown: Hundreds of dozens Red:
What time is it orange: how many dozen k yellow: hundreds of dozens of k green:
What time is it and how many m is blue: how many are in the dozens.
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Anonymous users2024-02-02Define the formula: r= l s
Variation of Ohm's law: r=u i
Resistance series: r=r1+r2+r3+.rn
You will know that the color ring resistance generally has four rings and five rings, the first two rings of the four rings represent the number, the third ring represents the number of 0, and the fourth ring is generally silver and gold, silver means an error of 10%, and gold is 5%. The five rings are the same, the first three represent ten white, the fourth represents the number of 0, and the five rings indicate that the error is silver and gold. I forgot how much the specific color represents. >>>More
Example 1The three-ring resistor is green, brown, and orange. Clause. >>>More
It is made by using high-temperature vacuum coating technology to tightly attach carbon to the surface of the porcelain rod to form a carbon film, and then cut it with appropriate joints, and coat its surface with epoxy resin to seal and protect. Its surface is often coated with green protective paint. The thickness of the carbon film determines the magnitude of the resistance, and the resistor is usually controlled by controlling the thickness and notch of the film.
For DC circuits, the resistance value of the capacitor is infinite. For AC circuits, the resistance value of the capacitance is related to the frequency of the AC and the capacitance of the capacitance, which is called capacitive reactance. There is a formula for calculating it.
Measuring DC resistance is an important item in transformer experiments. After measurement, the conductive circuit of the equipment can be inspected for defects such as poor contact, poor welding, coil failure, and wiring failure. In the actual measurement of small and medium-sized transformers, the DC bridge method is mostly used. >>>More