Series, Parallel and Combinations Circuits

Series Circuits

A series circuit is a circuit in which the resistors are connected end to end, so the current has only one path to take. The current is the same through each resistor. The total resistance of the circuit is found by simply adding up the resistance values of the individual resistors.

Equivalent resistance of resistors in series: R = R1 + R2 + R3

Here,

V = Voltage source

I = Current flowing in the circuit 

R1, R2, R3 = Resistance of resistors 

Voltage across R1 = I x R1 = V1 

Voltage across R2 = I x R2 = V2 

Voltage across R3 = I x R3 = V3 

Total voltage = IR1 + IR2 + IR3

V = V1 + V2 + V3

V = I(R1 + R2 + R3) V/I = R1 + R2 + R3

V = I x R = R1 + R2 + R3

Parallel Circuits

A parallel circuit is a circuit in which the resistors are arranged in such a manner that positive ends are connected to positive ends of the other resistors. Same applies to the negative ends. The current in parallel circuit is not same. Different currents are flowing through all the parallel paths.

Here, current I = I1 + I2 + I3

The voltage across each resistor in parallel is the same. The total resistance of a set of resistors in parallel is found by adding up the reciprocals of the resistance values, and then taking the reciprocal of the total.

Series-Parallel Circuits

A series–parallel circuit is the combination of a series circuit and a parallel circuit. Equivalent resistance of a series-parallel circuit depends on the number of series and parallel circuit forms in the circuit.

Here, equivalent resistance of the circuit: R = R3 II R2 and this parallel combination is in series with R1.