Table of Contents
This guide provides a straightforward approach to calculating voltage, current, and resistance in direct current (DC) circuits. Understanding these calculations is essential for designing and troubleshooting electrical systems.
Basic Concepts
In DC circuits, three main quantities are interconnected: voltage (V), current (I), and resistance (R). Ohm’s Law describes their relationship: V = I × R. This formula allows you to calculate any one of these values if the other two are known.
Calculating Voltage
To find voltage, multiply the current flowing through the circuit by its resistance. For example, if a circuit has a current of 2 amperes and a resistance of 5 ohms, the voltage is:
V = I × R = 2 A × 5 Ω = 10 V
Calculating Current
Current can be calculated by dividing the voltage by resistance. For instance, if a circuit has a voltage of 12 volts and resistance of 4 ohms, the current is:
I = V ÷ R = 12 V ÷ 4 Ω = 3 A
Calculating Resistance
Resistance can be found by dividing voltage by current. For example, if the voltage is 9 volts and the current is 3 amperes, the resistance is:
R = V ÷ I = 9 V ÷ 3 A = 3 Ω
Summary
- Use V = I × R to find voltage.
- Use I = V ÷ R to find current.
- Use R = V ÷ I to find resistance.