electrical current

• Electric current


  The flow of electrons
• Current


  • It is conserved at a junction
• Current in a series circuit

  Differs from current in a parallel circuit
• Voltage in a series circuit

  Differs from voltage in a parallel circuit
• Series circuit


  • Bulbs get dimmer when another bulb is added
• Parallel circuit


  • Bulbs do not get dimmer when another bulb is added
• Ammeter


  Measures current, connected in series
• Voltmeter


  Measures voltage, connected in parallel
• Current is conserved at a junction
• Current is the same in a series circuit
• Current is different in a parallel circuit
• Current is the flow of electrons
• Voltage is the energy transferred to a circuit
• Voltmeters are connected in parallel
• Ammeters are connected in series
• Adding another bulb to a series circuit makes the bulbs dimmer
• Adding another bulb to a parallel circuit does not make the bulbs dimmer
• Current is not measured by a voltmeter
• Series circuit


  When two or more components are connected in series, the same current flows in each component
• Parallel circuit


  When two or more components are connected in parallel, the current flowing in the circuit is shared between the components

  
• Resistance

  How easy or difficult it is for a current to flow
• We can add a resistor to a circuit to decrease the current flowing through it
• Measuring resistance

  There is no device to measure resistance in a circuit, so we calculate it using an equation
• Current

  Measured in Amps (A)
• Voltage

  Measured in Volts (V)
• Resistance

  Measured in Ohms (Ω)
• Using V = IR

  1. V = Voltage (V)

  2. I = Current (A)

  3. R = Resistance (Ω)

  
• Using V = IR

  • For a bulb with V = 10V, I = 2A, R = V/I = 10/2 = 5Ω
  • For a circuit with V = 20V, I = 2A, R = V/I = 20/2 = 10Ω
• An ammeter should be connected in series to measure current
• A voltmeter should be connected in parallel to measure voltage
• Voltage and current

  As voltage increases, current increases
• Sam and Jo carried out an investigation to see how the current in the circuit changed when they changed the voltage. They used different circuits.
• Electric current


  The flow of electrons
• Current


  The rate of flow of charge
• Current is the flow of electrons, which are negative charge
• Electrons can flow


  Because they are negative charge
• Series circuit


  • Current is the same throughout the circuit
  • Voltage only shares in a series circuit
• Parallel circuit

  • Current is different in each branch
  • Voltage is the same across each branch
• Measuring current in a circuit

  1. Ammeter connected in series

  2. Voltmeter connected in parallel
• Adding another bulb to a series circuit

  The bulbs get dimmer