AC Circuits

• Initial settings:
  • Select "Voltmeter" and "Ammeter" from the "Tools" menu on the right.
  • Select "Schematic" from the "Visuals" menu on the right.


• Activity 1: Voltage across the elements in RC circuit.
  
  • Build a R-C circuit and connect it to an AC source
    • Click on a resistor, capacitor and AC source and drag them into the circuit board.
    • Drag wires and connect the elements in series to form an RC circuit. Two elements are connected when their ends overlap. To disconnect two elements, right-click on the joint and select "split junction".
    • To change the values for an element, right-click over that element and select change value.

      R (Ohm)	C (F)	E0(V)	f (Hz)
      10	0.02	10	1

  • Perform the experiment:
    • Using the voltmeter, measure the voltage across each element. Write it down in a table.
    • Break the connection between R₁ and junction p.A and connect an ammeter. Record the value of the current through R₁.
    • Break the connection between R₂ and junction p.A and connect an ammeter. Record the current through R₂.
    • Break the connection between R₃ and junction p.A and connect an ammeter. Record the current through R₃.
  • In your lab notebook, write down the data in the following format:
    
    

    Resistor	Resistance (Ohm)	Current (A)	Voltage (V)
    R1
    R2
    R3

    
    
  • Results: Is the total current through R₁ and R₂ equal to that through R₃? Is the sum of the voltages across R₁ and R₃ equal to that of the battery?
  
  
• Activity 2: Voltage across the elements in RL circuit
  
  • Additional Settings:
    • Un-click "Voltmeter" from the "Tools" menu on the right.
    • Using three resistors, a light bulb, an ammeter, and a battery, construct the circuit shown above.
    • Set the values for R₁, R₂, R₃, and the Battery as:

      R1(Ohm)	R2(Ohm)	R3(Ohm)	Voltage (V)
      48	16	81	10

    • Drag and connect an ammeter between junction points A and B.
  • Perform the experiment:
    • Repeatedly, right-click and change the resistance of the lightbulb until the current through the ammeter is zero.
    • Record the value for the resistance of the light bulb.
    • Measure the voltage across each resistor and record the values in your notebook.
  • In your lab notebooks, write down the data in the following format:
    
    

    Resistor	Resistance (Ohm)	Voltage (V)
    R1
    R2
    R3
    Lightbulb

    
    
  • Results: Compare the ratios R₁/R₂ vs. R₃/R_lightbulb. Are they equal? Compare V₁ and V₃. Are the equal? Compare V₂ and V_lightbulb. Are they equal?How much is V₁+V₂? How much is V₃+V_lightbulb?
• Bring your notebook to our next class!