Physics: Electricity and Circuits

Physics: Electricity and Circuits

Basics of Electricity

  • Electricity is a form of energy resulting from the movement of charged particles, such as electrons, proton, and ions.

  • In the language of physics, the term electric charge is used to describe these basic properties of matter that cause it to experience a force when in an electromagnetic field.

  • There are two types of electric charges: positive and negative. Like charges repel each other, and unlike charges attract.

Electric Circuit

  • An electric circuit is a complete, closed path for electric current to flow.

  • It is made up of active elements like batteries and passive components like resistors, capacitors and inductors.

  • The most common components are the power source (like a battery), conductive path (like wires), and load that uses the electric power (like a bulb or motor).

Ohm’s Law

  • Ohm’s law is one of the fundamental laws in electricity, stating that current passing through a conductor is directly proportional to the voltage across it, provided the temperature remains constant.

  • Mathematically, Ohm’s law is expressed as V = IR, where:

    • V represents the voltage measured across the conductor (in volts)
    • I represents the current through the conductor (in amps)
    • R represents the resistance of the conductor (in ohms)

Circuit Diagram

  • A circuit diagram is a graphical representation of an electric circuit, using standard symbols for different components.

  • For instance, a cell or battery is usually represented by a long line (positive terminal) and a short line (negative terminal), a bulb by a circled cross and a resistor by a jagged line.

Types of Circuits

  • There are two primary types of electrical circuits: series and parallel.

  • In a series circuit, all components are connected end-to-end along a single path, so the same current flows through all of them.

  • In a parallel circuit, components are connected across common points or junctions, resulting in multiple paths for current to flow. If one path breaks, current can still flow along the other paths.

Circuit Analysis

  • Circuit analysis is the process of determining voltage, current, and power in each component in an electrical circuit.

  • Tools used for circuit analysis include Ohm’s law, Kirchhoff’s laws, Norton’s theorem, Thevenin’s theorem, and Superposition theorem.

  • It’s critical to keep in mind the conservation of energy and conservation of charge principles when analysing circuits.