Most of the film resistors of the type of metal layer has a nominal value of a typical power dissipation of 250mW sebasar up to a nominal value of 2W. In the resistor wire windings are made by wrapping the resistance wire in an insulating material. Resistance of materials commonly used is chromium-nickel (nichrome), the compounds of nickel (Eureka), and compounds of nickel and silver. The process of making is done by pulling the wire by using a molding machine that has been resized and then plated in order to produce good-quality.
Wire that has been formed, must have good uniformity, can be easily formed, corrosion resistant, and has a fairly high resistivity. Malleable ability is one of the essential requirement, thus if the wire is wound, it will not easily cracked or broken. Characteristics and patterns of failure of the resistor depends on the type of material used, method of manufacture, operation and environmental situation, as well as the resistance value.
At the time of operation, each resistor must dissipate power. At low temperature conditions can be dissipated around the large amount of power, but for lower power dissipation will result in a better level of stability with a lower error rate. Because in general the resistor has a uniform shape and construction, the rise in temperature caused by power terdisipasikan be maximum in the middle of the resistor body. This process is called the temperature of hot spots.
Figure 3.7. physical resistor
Figure 3.8. Fixed resistor color code
Example of How to read resistors with 4 color code
Ribbon-1 = RED = 2 (Value digits to-1)
Ribbon-2 = PURPLE = 7 (2nd digit value)
Pita 3rd = YELLOW = 1K = 1000 (Factor Multiplier)
Pita 4th = GOLD = 5% (Tolerance)
Jawabannnya is 27 x 1000 = 27,000 ± 5% ± 5%
R max = 27.000 + (5% x 27,000) = 28 350 Ω
R min = 27,000 – (5% x 27,000) = 25,650 Ω
Example of How to read a resistor with 5 color code
Ribbon-1 = BLUE = 6 (Score digits to-1)
Ribbon-2 = RED = 2 (2nd digit value)
Pita 3rd = BROWN = 1 (Rated digit 3rd)
Pita 4th = BROWN = 10 (Factor Multiplier)
Pita 5th = BROWN = 1% (Tolerance)
The answer is: 621 x 10 ± 1% = 6.210 ± 1%
R max = 7,540 + (1% x 7,540) = 7615.4 Ω
R min = 7540 – (1% x 7,540) = 7464.6 Ω
With a temperature coefficient of 50 ppm.
Example of How to read resistor color code 6
Ribbon-1 = PURPLE = 7 (Score digits to-1)
Ribbon-2 = GREEN = 5 (2nd digit value)
Pita 3rd = YELLOW = 4 (Rated digit 3rd)
Pita 4th = BROWN = 10 (Factor Multiplier)
Pita 5th = BROWN = 1% (Tolerance)
Ribbons to 6th = RED = 50 ppm (temperature coefficient)
The answer is: 754 x 10 = 7,540 ± 1% ± 1%, 50 ppm
R max = 7,540 + (1% x 7,540) = 7615.4 Ω
R min = 7540 – (1% x 7,540) = 7464.6 Ω
With a temperature coefficient of 50 ppm.