System of resistors Formula

System of resistors:

Let’s study some basic examples to study the combination of resistors.

Resistors in series:

The equivalent resistance of combination of resistance connected in series is given by,

1) Equivalent resistance , R_s = R₁ + R₂ + R₃

Resistors in parallel:

The equivalent resistance of combination of resistance connected in parallel is given by,

Ex. 1) Find the equivalent resistance in following circuit if value of each resistance is 10 Ω

Solution: Data, R₁=10 Ω, R₂=10 Ω, R₃=10 Ω, R₄=10 Ω

As we can see in the figure above, resistors R₂ & R₄ are connected in parallel, so their equivalent resistance can be obtain as

Hence the equivalent resistance of circuit is .25Ω

Ex. Find the value of current in following circuit.

Solution: Data,

Let R₁=10 Ω, R₂=20 Ω, R₃=20 Ω, R₄=20 Ω, R₅=25 Ω

V= 220 V

To find total current ‘I’, first we need to find total resistance of circuit.

As we can see in diagram, R₂, R₃ and R₄ are connected in parallel, then equivalent resistance of this part circuit is say R_P

I = V/R

∴ I = 220/41.67

∴I = 5.28 A

Hence 5.28 A current will be flow through the given circuit.