P4: Electric Circuits

• Circuit Symbols:

  A) Open Switch

  
• Circuit Symbols:

  A) Closed Switch

  
• Circuit Symbol:

  A) Lamp

  
• Circuit Symbol:

  A) Voltmeter

  
• Circuit Symbol:

  A) Ammeter

  
• Circuit Symbol:

  A) Resistor

  
• Circuit Symbol:

  A) Thermistor

  
• Circuit Symbol:

  A) Variable Resistor

  
• Circuit Symbol:

  A) Diode

  
• Circuit Symbol:

  A) LED

  
• Circuit Symbol:

  A) Fuse

  
• Circuit Symbol:

  A) Cell

  
• Circuit Symbol:

  A) Battery

  
• Circuit Symbol:

  A) LDR

  
• Electric current

  The flow of electric charge around a circuit. It is measured in amperes (A).
• Potential difference (voltage)

  The work done to move a charge between two points in a circuit. It is measured in volts (V).
• Resistance

  A measure of how much a component reduces the current flow through it. It is measured in ohms (Ω).
• Ohm's Law

  V=I×R (Voltage = Current × Resistance)
• Series circuit


  A circuit where components are connected end-to-end so that the current flows through each component in turn.
• Parallel circuit

  A circuit where components are connected across common points or junctions, providing multiple paths for the current.
• Electric charge

  Coulomb (C)
• Voltmeter

  A device used to measure the potential difference (voltage) across a component. It is connected in parallel.
• Ammeter


  A device used to measure the current flowing through a component. It is connected in series.
• Power in an electrical circuit

  The rate at which energy is transferred by the circuit. It is measured in watts (W).
• Electrical conductor

  A material that allows electric charge to flow through it easily, typically metals like copper and aluminum.
• Electrical insulator


  A material that does not allow electric charge to flow through it easily, such as rubber or glass.
• Current in a series circuit if one component fails

  The entire circuit stops working because the path is broken.
• Current in a parallel circuit if one branch fails

  The current can still flow through the other branches.
• Length of a conductor

  The longer the conductor, the greater the resistance.
• Cross-sectional area of a conductor

  The larger the cross-sectional area, the lower the resistance.
• Fuse in an electrical circuit

  To protect the circuit by breaking the circuit if the current is too high, preventing damage and fire.
• Alternating current (AC)

  Current that changes direction periodically.
• Direct current (DC)

  Current that flows in one direction only.
• Diode

  A component that allows current to flow in only one direction.
• Thermistor

  A resistor whose resistance decreases as the temperature increases.
• LDR (Light Dependent Resistor)

  A resistor whose resistance decreases as the light intensity increases.
• Characteristic of a diode

  Current flows easily in one direction (forward bias) but very little in the opposite direction (reverse bias).