A Simple Electric Circuit — Interactive Diagram
See why a bulb only glows when the circuit is complete, and which way the current flows.
TL;DR: See why a bulb only glows when the circuit is complete, and which way the current flows.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
A Simple Electric Circuit: See why a bulb only glows when the circuit is complete, and which way the current flows.
Why it matters: Open vs closed circuits and the direction of conventional current are the foundation of all electricity chapters and practicals.
A Simple Electric Circuit — Step by Step
- A circuit needs a CELL (battery), a BULB and connecting WIRES. With the switch OPEN, there is a gap — no current flows, so the bulb stays off.
- Close the SWITCH and the loop is complete. CURRENT flows from the + end of the cell, through the bulb, lighting it up. ✨
- Conventional current flows from + to − around the loop. Break the loop anywhere and the bulb goes out.
Quick Notes — the Exam Crux
- A circuit is a closed conducting loop through which current flows.
- Main parts: a cell/battery (source), connecting wires, a bulb/load, and a switch.
- Closed circuit = complete loop → current flows → bulb glows. Open circuit = a gap → no current.
- Conventional current flows from the + terminal to the − terminal in the external circuit.
- A switch simply opens or closes the loop.
- Conductors (metals) allow current to pass; insulators (plastic, rubber) do not.
Remember It (Memory Trick)
A circuit needs a closed loop: cell → wire → bulb → back to the cell. "Break the loop, break the flow." Conventional current flows from + to − (electrons actually move − to +).
Real-Life Example
A torch lights only when you slide the switch to complete the loop — flick it off and you create a gap (open circuit), so the current stops instantly.
Test Yourself
Why does a bulb not glow when the switch is open?
The loop is broken (open circuit), so no current can flow.
In which direction does conventional current flow?
From the positive terminal to the negative terminal of the cell (in the external circuit).
Name one conductor and one insulator.
Conductor: copper (a metal). Insulator: rubber or plastic.
📖 Read the full explanation of A Simple Electric Circuit →
More Visual Lessons
- Dispersion of Light (Prism)
- How We Hear (Sound)
- Electromagnetic Induction
- Refraction of Light
- Series vs Parallel Circuits
- Magnetic Field of a Bar Magnet
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