V = IR • Kirchhoff’s Laws • Series • Parallel • Mixed — Simulate • Explore • Practice • Quiz
Ohm’s Law is the foundational equation of electrical engineering: V = IR, where V is voltage in volts, I is current in amperes, and R is resistance in ohms. It tells us that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance. This simple relationship governs everything from LED circuits to industrial power distribution. Our interactive simulator lets you build single-resistor, series, parallel, and mixed DC circuits and observe how voltage, current, and resistance interact in real time with animated current dots flowing through the wires.
Kirchhoff’s Current Law (KCL) states that the total current entering a junction equals the total current leaving it — charge is conserved. Kirchhoff’s Voltage Law (KVL) states that the sum of all voltage drops around any closed loop equals the supply voltage — energy is conserved. In our simulator, you can verify both laws by switching between series and parallel circuit configurations. In a series circuit, the same current flows through every resistor and voltages add up to the supply. In a parallel circuit, the same voltage appears across every branch and currents add up to the total.
A series circuit has all components connected end-to-end, so Rₙₒₙ = R1 + R2 + ... and the current is the same everywhere. A parallel circuit has components connected across the same two nodes, so 1/Rₙₒₙ = 1/R1 + 1/R2 + ... and the voltage is the same across every branch. A mixed circuit combines both topologies — for example, R1 in series with a parallel combination of R2 and R3. The simulator calculates total resistance, individual voltage drops, branch currents, and power dissipation for each component automatically.
Electrical power is calculated using P = VI = I²R = V²/R. Every resistor converts electrical energy into heat. The simulator displays total circuit power and individual component power so you can see which resistor dissipates the most energy. This is critical for selecting appropriate resistor wattage ratings in real-world designs.
This simulator is designed for electrical and electronics engineering students, physics students studying DC circuits, technical trainees learning about circuit analysis, and instructors teaching Ohm’s Law, Kirchhoff’s Laws, or basic circuit theory. It provides visual, hands-on understanding of current flow and voltage distribution without requiring laboratory equipment or simulation software.