Equivalent Resistance is a single value of resistance that replaces a number of resistors connected in a circuit, hence making the analysis simpler. Using it one can figure out how the whole network of resistors would behave in terms of current flow and voltage drop.

Electrical resistance is the amount of energy one needs when you move charges/current through your devices. If you require a lot of energy, then the amount of required resistance is also high.The equivalent resistance of a network is that single resistor which could replace the entire network in such a way that for a certain applied voltage V you get the same current I as you were getting for a network.

Formula 

Equivalent resistance formula for series resistance is represented as,

Equivalent resistance formula for parallel resistance is expressed as,

Where, R1, R2….Rn the given resistors.

Solved Problems

Problem 1: Calculate the equivalent resistance if 3Ω, 20Ω and 32Ω are connected in series.

Solution :

Same resistance in parallel is given by

R= R1 x R2 x…….x Rn

R = 3 Ω x 20 Ω x 32 Ω

R = 55 Ω.

Problem 2: If 34 Ω and 20 Ω is joined in parallel, then what is the equivalent resistance?

Solution:

Resistance in parallel is given by,

 

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