Equivalent resistance

Definition

Equivalent resistance is the total resistance of a combination of resistors connected either in series or parallel. It simplifies complex circuits into a single resistor value that has the same effect on the circuit.

5 Must Know Facts For Your Next Test

1. In series circuits, equivalent resistance is the sum of all individual resistances: $R_{eq} = R_1 + R_2 + ... + R_n$.
2. In parallel circuits, equivalent resistance is found using the reciprocal sum: $\frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + ... + \frac{1}{R_n}$.
3. Equivalent resistance affects the overall current and voltage distribution in a circuit.
4. For two resistors in parallel, $R_{eq}$ can also be calculated by $R_{eq} = \frac{R_1 R_2}{R_1 + R_2}$.
5. Determining equivalent resistance helps in analyzing and simplifying complex electrical networks.

Review Questions

• How do you calculate equivalent resistance for resistors connected in series?
• What formula is used to find equivalent resistance for resistors connected in parallel?
• Why is it important to determine the equivalent resistance of a circuit?

Related terms

Series Circuit:

A type of electrical circuit in which components are connected end-to-end so that current flows through each component sequentially.

Parallel Circuit: A type of electrical circuit in which components are connected alongside each other so that current can flow through multiple paths.

Ohm's Law:

$V = IR$, where $V$ is voltage, $I$ is current, and $R$ is resistance; it describes the relationship between voltage, current, and resistance.