Keshu

CONDUCTORS AND INSULATORS (IN DETAIL)

What are Conductors?

Conductors are materials that allow electric current to flow easily through them. This happens because they have free electrons that can move when a voltage is applied.

Why Conductors Conduct Electricity

• Atoms in conductors have loosely bound outer electrons

• These electrons move freely from atom to atom

• When a battery or power source is connected, electrons start flowing

Common Conductors

• Metals: copper, aluminum, silver, gold, iron

• Graphite (carbon)

• Salt water

• Human body (because it contains water and salts)

Uses of Conductors

• Electric wires (copper or aluminum)

• Electrical contacts in switches

• Circuit boards

• Power transmission lines

What are Insulators?

Insulators are materials that do not allow electric current to flow easily. Their electrons are tightly bound to their atoms.

Why Insulators Do Not Conduct

• Electrons cannot move freely

• Very high resistance to electric current

• They block or reduce the flow of electricity

Common Insulators

• Rubber

• Plastic

• Glass

• Dry wood

• Air

• Paper

Uses of Insulators

• Covering electric wires

• Handles of electrical tools

• Preventing electric shocks

• Separating conducting parts in circuits

ELECTRIC CURRENT (IN DETAIL)

What is Electric Current?

Electric current is the rate of flow of electric charge through a conductor.

In simple words:Electric current is how fast electrons are moving through a wire.

Unit of Electric Current

• SI unit: Ampere (A)

• Measured using an ammeter

Formula of Electric Current

Electric current is given by:

I = Q / t

Where:

• I = electric current (ampere)

• Q = charge (coulomb)

• t = time (seconds)

Types of Electric Current

1. Direct Current (DC)

• Current flows in one direction

• Source: batteries, cells

• Used in electronics, mobile phones

2. Alternating Current (AC)

• Current changes direction periodically

• Source: power stations

• Used in homes and industries

Effects of Electric Current

1. Heating Effect

   • Electric current produces heat

   • Used in heaters, irons, bulbs

2. Magnetic Effect

   • Current creates a magnetic field

   • Used in motors, electromagnets

3. Chemical Effect

   • Causes chemical reactions

   • Used in electroplating, batteries

Factors Affecting Electric Current

• Voltage (potential difference)

• Resistance of the conductor

• Length and thickness of the wire

• Material of the wire

ELECTRIC CIRCUIT SYMBOLS (IN DETAIL)

What are Circuit Symbols?

Circuit symbols are standardized signs used to represent electrical components in a circuit diagram.

They make circuits:

• Easy to draw

• Easy to understand

• Same worldwide

Common Circuit Symbols and Their Meaning

1. Electric Cell

   • Provides electrical energy

   • One long line (positive) and one short line (negative)

2. Battery

   • Combination of two or more cells

   • Multiple long and short lines

3. Switch (Open)

   • Circuit is broken

   • No current flows

4. Switch (Closed)

   • Circuit is complete

   • Current flows

5. Bulb (Lamp)

   • Converts electrical energy into light

6. Resistor

   • Limits the flow of current

7. Variable Resistor (Rheostat)

   • Resistance can be changed

8. Ammeter

   • Measures current

   • Connected in series

9. Voltmeter

   • Measures voltage

   • Connected in parallel

10. Connecting Wire

    • Joins components

    • Straight line

Importance of Circuit Symbols

• Used in textbooks, exams, and engineering

• Help in designing circuits

• Avoid confusion

• Save time and space