A process called resistor color coding is used to determine the value of resistance for a resistor, just as shown in the below figure. A resistor is coated with four color bands where each color determines a particular value. The below table shows a list of values which each color indicates.
The first two colored bands indicate the first and second digit of the value and the third color band represents the multiplier (number of zeroes added). The fourth color band indicates the tolerance value for RESISTOR COLOR CODING .
Tolerance is the range of value up to which a resistor can withstand without getting destroyed. This is an important factor. The following figure shows how the value of a resistor is determined by color code.
The five color band resistors are manufactured with tolerance of 2% and 1% and also for other high accuracy resistors. In these five band resistors, the first three bands represent digits, fourth one indicates multiplier and the fifth represents tolerance.
The resistance offered to the alternating current because of the capacitances and inductances present in the circuit, can be understood as reactance. When alternating current goes through a pure reactance, a voltage drop is produced that is 90°out of phase with the current.
Impedance is the effective resistance to alternating current arising from the combined effects of ohmic resistance and reactance. When alternating current goes through an impedance, a voltage drop is produced which is somewhere between 0°to 90°out of phase with the current.
A Resistor when connected in a circuit, that connection can be either series or parallel
The total amount of Current that flows through a set of resistors connected in series is the same at all the points throughout the resistor network.
The total voltage that appears across a Parallel resistors network is same as the voltage drops at each individual resistance.