Calculating Current and Power in Series and Parallel Dc Circuits: Step-by-step Approach

Understanding how to calculate current and power in DC circuits is essential for designing and analyzing electronic systems. This article provides a clear, step-by-step approach to calculating these parameters in both series and parallel configurations.

Calculating in Series Circuits

In a series circuit, components are connected end-to-end, forming a single path for current flow. The total resistance is the sum of individual resistances:

R_total = R₁ + R₂ + … + R_n

The current through each component is the same and can be calculated using Ohm’s Law:

I = V_total / R_total

The power dissipated by each resistor is:

P = I² R

Calculating in Parallel Circuits

In a parallel circuit, components are connected across the same voltage source. The total current divides among the branches:

The equivalent resistance is calculated as:

1 / R_total = 1 / R₁ + 1 / R₂ + … + 1 / R_n

The total current supplied by the source is:

I_total = V_source / R_total

Power in each branch is calculated as:

P = V² / R

Summary of Steps

• Identify the circuit type (series or parallel).
• Calculate total resistance.
• Use Ohm’s Law to find current or voltage.
• Calculate power using P = I² R or P = V² / R.