Electric Curciuts

• BASIC CIRCUITS - series - one path current

  
• BASIC CIRCUITS - Parallel - more than one path for current

  
• This is the circuit symbol for cell

  
• This is the circuit symbol for switch

  
• This is the circit symbol for wire

  
• In everyday life we use electrical circuits, name three examples

  • charge a device / sockets
  • switch on a light switch
  • kitchen appliances (electric)
• LED stands for

  Light emitting diode
• LDR stands for

  light dependent resistor
• What is LED used for ?

  Converts electrical energy into light when current flows in a specific direction
• What is LDR used for ?

  Changes resistance depending on light intensity
• What is a thermistor used for ?

  Changes resistance depending on temperature
• What is a diode used for ?

  Allows current to flow in one direction only
• What is a fuse used for ?

  Melts if too much current flows to prevent over heating
• What is A voltmeter used for ?


  Measures voltage
• What is an ammeter used for ?

  Measures the current
• What is a resistor used for ?

  Restricts the current flow
• What is a variable resistor used for ?


  Allows voltage / current to be varied. Also known as a dimmer switch
• what is a open switch used for ?

  It stops current from flowing by breaking the circuit
• What is a closed switch used for ?

  Allows current to flow
• In parallel circuit, current splits across branches
• More current flows where there is fewer bulbs because there is less resistance
• In a series circuit, the current is the same in every direction of the circuit
• In series circuit, the voltage splits across components
• In a parallel circhit, the current splits at junctions
• In a parallel circuit, the voltage is the same across avery branch
• Resistance is mesurednin units called ohms (Ω)
• Each component in a circuit has a resistance
• Resistance (R) is a measure of how difficult it is for current or flow
• This is a fixed resistor

  
• This is a variable resistor

  
• Remember this equation

  
• The symbol for voltage is - V
• The symbol for current is - I
• The symbol for resistance is - R (ohms)
• To rearrange the equation use the triangle

  
• To calculate the R total = R1 + R2 + R3