Created By : awnish

Reviewed By : Rajashekhar Valipishetty

Last Updated : Apr 10, 2023

Our Series Resistor Calculator is a free tool that determines the equivalent resistance or missing resistor value in a series ciruit easily by taking the resistance of the resistors. Just you have to provide the required input details and click the calculate button to check the equivalent resistance in a short span of time.

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Resistor 1 (R1)
Resistor 2 (R2)

How to Find Resistance in Series Circuit?

Check out the step by step process that helps to compute the equivalent resistance in a series circuit. Follow these steps to get the result effortlessly.

  • Get the resistances of all resistors that are connected in series.
  • Add those resistances to get the total resistance.

Resistors in Series Formula

A resistor is a device that can be used for either regulating or limiting the current flow in the circuit. Its SI unit is Ohm. These resistors can be connected either in series or parallel in a circuit. If the resistors are connected in series, then a common current flows through all of them. So, total resistance will become the sum of individual resistances.

The formula to calculate the equivalent resistance is

R = RΓéü + RΓéé + RΓéâ + . . . Rn

Missing Resistance formula is RΓéé = R - (RΓéü + RΓéâ + . . . Rn)


R is the equivalent series resistance

RΓéü, RΓéé, RΓéâ, . . . Rn are the resistances of individual resistors

Resistors in Series


Question: If 4 resistors are connected in series and their resistances are 4 Ω, 10 Ω, 15 Ω, 22 Ω find the total resistance in the circuit?


Given that

First resitor resistance RΓéü = 4 Ω

Second resistance RΓéé = 10 Ω

Third Resistance RΓéâ = 15 Ω

Fourth Resistance RΓéä = 22 Ω

Equivalent series resistance R = RΓéü + RΓéé + RΓéâ + RΓéä

R = 4 + 10 + 15 + 22

= 51 Ω

Therefore, equivalent series resistance is 51 Ω.

Physicscalc.Com has plenty of calculators at one page, just take the help from the required calculator to achieve the results accurately at a faster pace and also understand the concept by taking the help of provided steps.

Frequently Asked Questions on Series Resistor Calculator

1. What is the rule for resistors in series?

If the resistors are connected in series in a circuit, then the current flows through all resistors are the same. Here, the total of all the potential differences is equal to the potential difference of the supply. The total resistance in the circuit will be the sum of resistances of the resistors that are in series connection.

2. What are the advantages of series resistors?

The following are the advantages of the series connection of resistors:

  • If we connect resistors in series, then the total circuit resistance increases thus the current decreases.
  • When the electrical appliances are connected in series, the applied voltage is divided to not give light efficiently.
  • Damage of resistors can be prevented by connecting in series.

3. How to calculate the equivalent resistance in a series circuit?

When the resistors are connected in series, then its total resistance will be the sum of the resistances in the circuit. Its formula is R = RΓéü + RΓéé + RΓéâ + . . . Rn.

4. What are the two main types of resistors?

The resistor is an electrical component that is having two terminals used for either limiting or regulating the electric current flow in electrical circuits. The two types of resistors are linear resistors, non-linear resistors. If the resistor value changes with a change in applied voltage, the temperature is a linear resistor and if it is independent of ohms law, then it is the non-linear resistor.