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Overview
An electric circuit is a system of connected components that allows current to flow when a voltage source provides a potential difference and the path is complete. Circuits can transfer electrical energy into light, heat, motion, sound, computation, communication, storage, and control.
Complete Path
A circuit must provide a continuous conducting path for steady current. If the path is broken, the circuit is open and current stops.
Circuit Components
Common components include batteries, wires, resistors, switches, capacitors, lamps, motors, diodes, sensors, and integrated circuits.
Source, Load, and Path
A source supplies voltage or electrical energy, a load receives energy, and the conducting path allows charge to circulate.
Schematic Diagrams
Circuit schematics use symbols to represent components and connections. They show electrical relationships rather than physical layout.
Series and Parallel Connections
Components can be connected in series, parallel, or combinations. The connection pattern determines current, voltage, resistance, and failure behavior.
Energy Transfer in Circuits
Charges transfer energy to components as they move through potential differences. Devices convert electrical energy into other useful or less useful forms.
Circuit Measurement
Voltmeters measure voltage across components. Ammeters measure current through components. Proper meter connection is essential for safe and accurate measurement.
Common Mistakes
A common mistake is thinking current leaves the battery and gets used up. Charge circulates, while energy is transferred to components.
Why This Matters in Physics
Circuits connect electricity to technology, electronics, power, communication, computing, lighting, motors, sensors, and control systems.