Resistors can be used in many ways besides resisting electric current. They can be used to divide voltage, match and load circuits, generate heat, fix time constraints, and control gain. Large resistors are used as electric power brakes in trains; thus, they enable the stored kinetic energy to be released. They are used to power LEDs and blower motors. There are fixed, variable, and physical quality resistors. Resistors are made of carbon composition, carbon film, metal film, thick and thin film, foil, or wire wound to resist electricity. Here are details about resistors that you should know:
You can identify a current sense resistor using color-coding. The resistance and tolerance values of a resistor are displayed by several colored bands. Most resistors have four colored bands. The color bands are painted on the resistor’s body. The first two bands show the primary digits of the resistance value. The third band represents the multiplying factor (which determines the resistance value). The last band shows the tolerance value.
SMD resistors cannot be identified by the color-coding method because they are not large enough. They have the numeric based code because of their small sizes. All SMD resistors are of the same size; hence the manufacturing process is standardized for all of them using the rapid-fire pick-and-place machines.
When choosing a resistor, there are three simple steps to follow. First, calculate the resistance that you need using Ohm’s Law. Use a standard formula. Determine your voltage and current. Click here to get the best custom wirewound resistor.
Calculate the power rating. This is the amount of power the resistor will dissipate. In the formula where P (power in Watts), V (voltage drop across the resistor), and R (resistance of the resistor in Ohms) the power rating is calculated in the example below:
Your LED has a 4V voltage, the resistor has a 200 Ohm value, and the power supply is 10V. The amount of power that the resistor will dissipate is:
Find the voltage drop of the resistor:
10V - 4V = 6V
The voltage drop is used to find the watts:
P = 6V*6V / 200 Ohm = 0.18 Watts
After obtaining the resistance and power rating values, pick a standard resistor that will dissipate the amount of power that you need. Cheap products are expensive in the end because they need constant repairs, and they do not last long. Buy the resistor from the best brand in your location, but do not strain your pockets to get the most expensive one if there are several less costly but quality resistors to choose from. Read more on this link: https://en.wikipedia.org/wiki/Resistor.