Parallel Circuits

Example 1

Find out the total resistance for the following circuit

Solving R3 || R4

R3||R4 =

R3||R4 =

=4000 K Ohm

Redrawing the circuit.

R2||R34 =

=3000 Ohm

Redrawing the circuit.

R1||R234 =

=2500 Ohm

Example 2

Find total resistance in the following circuit

We know as per given data

R1= 40 Ohm

R2=30 Ohm

R3= 20 Ohm

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Characteristic 2 . Voltage across Parallel Resistor remain same

Resistors connected in parallel have same voltage across them . Lets say in the below figure , voltage across any resistance will be same.

Similarly if we change the position of voltmeter and try to calculate the voltage across some other resistance , we will observe that the voltage is same

Example 3 : Calculate the voltage across R3

As all resistors are in parallel , so voltage across all resistors will be same , that is 24 Volts. So

VR3= 24 V

Characteristic 3 : Current is different in parallel branches.

As with the flow of water, depending on the size of pipe, different amount of water will flow from the pipe .

Similarly different current will flow in each branch with respect to the resistance that is being offered.

Example 4 : Find the Current in all resistances.

We know that Voltage across all resistors in a parallel circuit is same . Relabeling the circuit

Now calculating current in all branches

Current Divider Formula with Two Branches