Conductors and Insulators

Conductors and Insulators

Material Categories Based on Electric Current Flow

Materials can be categorized into three types based on their ability to conduct electric current:

  • Insulators: Materials that do not allow electric current to pass through.

  • Conductors: Materials that allow electric current to pass through.

  • Resistors: Materials with intermediate conductivity.

Conductors

  • Definition: Any material that allows electric current to pass through it.

  • Examples:

    • Copper

    • Any metal

    • Aluminum

    • Steel

    • Gold

    • The human body

    • Earth

    • Animals

  • Function: Conductive materials (e.g., metal) are used for wires to carry electricity.

  • Property: Allow heat to be transmitted through them.

Insulators

  • Definition: Any material that does not allow electric current to pass through it.

  • Examples:

    • Plastic (like the protective coating on wires)

    • Cloth

    • Rubber

    • Wood

    • Glass

  • Function: Insulators like plastic and rubber are used as a covering for electric wires to make them safer to handle, protecting users from electric current.

  • Property: Resist the flow of current and, generally, do not allow heat to flow through them.

  • Nature: Generally solid.

Open and Closed Circuits

  • Open Circuit: A path for electric current that has a gap, preventing current flow. (e.g. light is off)

  • Closed Circuit: An unbroken path for electric current with no gaps, allowing current to flow. (e.g. light is on)

  • A circuit can be opened or closed by touching two wires together to allow or prevent current flow.

Ammeter

  • An ammeter is used to measure electric current.

  • It must be connected in series in the circuit.

  • The positive side of the ammeter must be connected nearest to the positive terminal of the battery (electric cell), and vice versa.

Electric Circuits

  • Electric circuits are made up of electrical components and connecting wires.

  • Components: light bulb, wires, battery

  • These components must be joined together without any gap to form a closed circuit.
    Note: Incomplete circuits are called open circuits.

  • An open circuit can occur when a connecting wire is missing or there is no source of electrical energy.