Component Resistor

     Resistors are the basic components of electronics that are used to limit the amount of current flowing in one circuit. As the name implies resistor is resistive and generally made ​​of carbon materials. From Ohms law is known, the resistance is inversely proportional with the amount of current flowing through it. Unit resistance of a resistor is called Ohm or denoted by the symbol W (Omega). Resistance to state power limits should be included. various kinds of resistors are made from different materials with different properties. other specifications to consider in choosing resitor on a bill other than a large resistance is his big watts. Because the resistors working with electrified, it will be a power dissipation of heat for W = I2R watts. The larger the physical size of a resistor can be demonstrated the greater ability of the resistor power dissipation. Generally in the market available sizes 1 / 8,1 / 4, 1, 2, 5, 10 and 20 watts. 

  Resistor which has a power dissipation of 5, 10 and 20 watts are generally cubic-shaped elongated rectangular white, but some are shaped the cylinder. But typically for this jumbo size resistor resistance value is printed directly dibadannya, for example 100W5W. Resistors in theory and practice in the representation letter written by R. Judging from physical size of a resistor with each other does not mean the same great value the obstacles. Resistance value of resistor is called resistance

 

Characteristics of Various Resistors      
Characteristics of various kinds of resistors are influenced by the materials used. Resistance  resistor composition is unstable due to the influence of temperature, if the temperature rises the resistance down.  Less appropriate when used in high voltage electronic circuits and large currents.  Resistance of a resistor composition is different between the reality of nominal resistance. If  difference in value to 10% of less well on the circuit that require high accuracy. Variable resistor resistance varies in accordance with the change of settings.  Variable resistor with a mechanical regulator, regulation by light, temperature regulation by  temperature or other settings.  If the value changes, the resistance of the potentiometer is proportional to the position of the sliding contact  the potentiometer are called linear potentiometer. But if the change in value  resistance is proportional to the position of the sliding contact is called potensio logarithmically.  In theory a pure resistor has a resistance expressed but at  practice, a resistor has the additional properties of inductive and capacitive properties.  

      On  essentially low value resistor and inductive properties tend to have high value resistors  additional resistor has a capacitive nature.  Temperature has a significant impact on an obstacle. In Conductor there are a number of free electrons is very large at all, and any heat energy imposed it will have little impact on the total number of free carriers. In fact heat energy will only increase the intensity of the random movement of particles that are in materials that make it more difficult for the general flow of electrons in any one direction are determined. The result is for a good conductor, the increase in temperature will resulted in increased prices prisoners. As a result, the conductor has a positive temperature coefficient.

 current > thermal
HR = I2Rt [joule]
Q = mc (Ta-T)
Q = 0.24 I2 R t [calories]

And Font Color Codes Resistor On
Not all of the resistance value of a resistor is included with the symbol number but with color-coded rings. The number of rings on each of resistor color code number 4 and there are also a number 5. Resistance that has 5 rings consists of rings 1, 2 and 3 is the ring digit, the ring 4 as multipliers and ring 5 is tolerance. Resistance that has four rings composed of ring 1, 2 is a digit, 3 is ring ring ring 4 as a multiplier and tolerance.

  Code Letter
1) Point I declare the value of the resistor and the decimal comma.
    If the letter I is: R means that x 1 (times one) ohm
                           K means x 103 (times 1000) ohm
                           M means x 106 (times 1 million) ohms
2) Letter II declared tolerance
    If the second letter is: A mean tolerance of ± 5%
                                     K means tolerance of ± 10%
                                     M means tolerance of ± 20%