Master electrical circuits through hands-on learning. Understand voltage, current, and resistance relationships with interactive circuit simulations and real-world examples.
Interactive Learning: Use our Ohm's Law Calculator alongside this tutorial for hands-on practice.
Before diving into Ohm's Law, let's understand the three fundamental electrical quantities:
Electrical pressure or potential difference
Measured in Volts (V)
Think: Water pressure in a pipe
Flow of electrical charge
Measured in Amperes (A)
Think: Water flow rate
Opposition to current flow
Measured in Ohms (Ω)
Think: Pipe diameter restriction
Imagine electricity like water flowing through pipes. Voltage is the water pressure, current is how much water flows per second, and resistance is how narrow the pipe is.
Ohm's Law describes the relationship between voltage, current, and resistance:
Cover the unknown value to see the formula!
Let's solve real circuit problems using Ohm's Law:
Given: 12V battery, 4Ω resistor
Find: Current (I)
Formula: I = V ÷ R
Solution: I = 12V ÷ 4Ω = 3A
Answer: 3 Amperes
Given: 9V battery, 1.5A current
Find: Resistance (R)
Formula: R = V ÷ I
Solution: R = 9V ÷ 1.5A = 6Ω
Answer: 6 Ohms
Given: 2A current, 8Ω resistor
Find: Voltage (V)
Formula: V = I × R
Solution: V = 2A × 8Ω = 16V
Answer: 16 Volts
Power (P) is the rate of energy consumption, measured in Watts (W). It relates to Ohm's Law:
Given: 120V household outlet, 10A current
Find: Power consumption
Solution: P = V × I = 120V × 10A = 1,200W = 1.2kW
This device uses 1,200 Watts of power
High power means high heat generation. Always ensure components are rated for the power they'll handle to prevent overheating and fire hazards.
A 3V LED draws 20mA (0.02A) of current.
Calculate the required resistance for a 9V battery.
A toaster uses 1,500W at 120V.
Find the current draw and internal resistance.
A car headlight has 2Ω resistance in a 12V system.
Calculate current and power consumption.