Resistors

are components manufactured to possess a specific value of resistance to the flow of current. it is the most commonly used component in an

electronic circuit. 

Resistors are available with fixed or variable resistance values. They are available in a variety of shapes and sizes to meet specific

circuit, space, and operating requirements

series and parallel configuration

series circuit contains two or more resistors and provides one path for current to flow. The current flows from the negative side of the voltage source through each resistor to the positive side of the

voltage source. If there is only one path for current

to flow between two points in a circuit, the

circuit is a series circuit.

The more resistors connected in series, the more opposition there is to current flow. The more opposition there is to current flow, the higher the resistance in the circuit. In other words, when a

resistor is added in series to a circuit, the total resistance

in the circuit increases. The total resistance in a series circuit is the sum of the individual resistances in the circuit. 

parallel circuit contains two or more resistors and provides two or more paths for current to flow. Each current path in a parallel circuit is called a branch. The current flows from the negative side

of the voltage source, through each branch of the parallel circuit, to the positive side of the voltage source. 

If there is more than one path for current to flow between two points in a circuit with two or more resistors, the circuit is a parallel circuit.

The more resistors are connected in parallel, the less opposition there is to current flow. The less opposition there is to current flow, the lower the resistance in the circuit. In other words, when a resistor is added in parallel to a circuit, the total resistance in the circuit decreases, because additional paths for current

flow are provided. In a parallel circuit, the total resistance is always less than the resistance of any branch.