Resistors and the way to read the markings
Resistors are the most prevalently used passive components. Resistors oppose the current flow in an electrical circuit. If there is a higher resistance in a circuit, the flow of current is small. When the resistance is decreased, the current flow rises. Resistance, voltage and current are related to each other by Ohm’s Law. The voltage across a resistor is measured in volts (V), the current across the resistor in A (amps) and the resistance is calculated in Ohms.
Types of resistor marking To show the value of the resistor they are marked with a numbered code or with color bands. Through-hole resistors tend to be labeled having a variety of colored bands, which is called the resistor color code. Each color symbolizes a number. In the case of a four band resistor, the first 3 color bands reveals the resistor value in ohms and the fourth band displays the tolerance. Resistors can by no means be made to a exact value and the tolerance band (the fourth band in this situation) tells us, making use of a percentage what the margin in resistance is, comparable to its coded value. SMD resistors are normally coded with a numerical value of three numbers. This means that the initial two numbers are the main numbers used significantly and the third is a factor that is multiplied to the order of 10. For instance,in case of a code of 102, the code would equate to 10 x 10^2 = 1 kOhm.