Electric Circuits

Build series and parallel circuits with resistors, bulbs, and switches

Electric circuits are closed loops where current (flowing electrons) carries energy from a source (battery) through components (resistors, bulbs) and back. Ohm's Law (V=IR) connects the three key quantities: voltage (V, the 'push' measured in volts), current (I, the flow rate in amps), and resistance (R, opposition to flow in ohms). In a series circuit, components are connected end-to-end — the same current flows through each, but voltage splits across them. Total resistance adds up: R_total = R1 + R2 + R3. If one bulb burns out, the circuit breaks and all bulbs go dark. In a parallel circuit, components connect across the same two points — each gets the full battery voltage, but current splits among them. Total resistance decreases: 1/R_total = 1/R1 + 1/R2 + 1/R3. If one bulb burns out, the others stay lit. That is why homes use parallel circuits: you can turn off one lamp without losing all electricity. Power (P=IV) tells you how much energy a component uses per second. A brighter bulb consumes more power.