OHM ZONE: VIRTUAL CIRCUIT BUILDING
Name_________________________
Ohm Zone provides you with a virtual circuit board which you can use to build electrical circuits
of various complexity. During this activity you will be asked to build a variety of circuits and take
specific voltage and current measurements.
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TIPS FOR USING OHM ZONE:
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Use the computer mouse to drag circuit components into position
Once the circuit is complete click on the “visualize” icon to see the direction of
Conventional current
Note: (a) Conventional current: positive to negative (based on the previous
incorrect idea that protons move along the wire)
(b) Electric current: negative to positive (movement of electrons)
Once you place a voltmeter or ammeter in the circuit, the readings for these meters are
displayed at the top of the circuit board
You can click on the pop-up icon so when your mouse is over a component information
about it is displayed
The hand icon has information and demos about circuit building
LET THE CIRCUIT BUILDING BEGIN!
Use the voltmeter to measure the voltage produced by the battery: ___________ V
Circuit #1: Connect a battery, switch and a bulb.
(a) Use the ammeter to measure the amount of current flowing through different parts
of the circuit.
Current = _______________ A
(b) Compare the current readings in different locations in the circuit. What do you
notice?
(c) How would you explain these readings?
Circuit #2: Connect a battery, switch and 2 bulbs in series.
(a) Use the ammeter to measure the amount of current flowing through different parts
of the circuit. Current = _____________ A
(b) Compare the current readings for circuit #1 and circuit #2. What do you notice and
how would you explain it?
Circuit #3: Connect a battery, switch and 3 bulbs in series.
(a) Draw a schematic diagram of this circuit.
(b) Show direction of electron flow on your diagram (caution: Ohm zone shows
conventional current which is opposite)
(c) Use the ammeter to measure the current flowing through different parts.
Current = __________ A
(d) Is the current reading what you would expect? Why or why not?
(e) Use the voltmeter to measure the voltage across each bulb
Bulb 1 voltage = __________ V
Bulb 2 voltage = __________ V
Bulb 3 voltage = __________ V
(i)
How would you explain these voltage readings?
(ii)
Voltmeters are connected in ______________.
Ammeters are connected in _______________.
(iii)
How do you find the total voltage in a series circuit?
Total current?
Circuit #4: Connect a battery, switch and 2 bulbs in parallel.
(a) Draw a schematic diagram of this circuit.
(b) Use the ammeter to measure the current flowing through these locations:
A1 (before battery) _____________ A
A2 (first bulb) _________________ A
A3 (second bulb) ________________ A
What do you notice about the readings in different parts of the circuit?
How would you explain this?
Circuit #5: Connect a battery, switch and 3 bulbs in parallel.
(a) Draw a schematic diagram of this circuit.
(b) Use the ammeter to measure the amount of current flowing through each bulb and
before or after the battery. Label the locations on your diagram where the ammeter
readings were taken.
A1 = _________ A
A2 = _____________ A
A3 = _________A
A4 = _____________ A
(c) Use the voltmeter to measure the voltage across each bulb
Bulb1 voltage = __________ V
Bulb2 voltage = ______________ V
Bulb 3 voltage = _________V
(i) How would you explain these voltage readings?
(ii) What voltage would you expect to record across a 4th bulb connected in
parallel? Check your prediction.
Predicted voltage = ___________ V
Measured voltage = ___________ V
(d) Show the direction of electron flow on your diagram.
Circuit #6: Connect a battery, ammeter and 2 blue resistors in series
(a) Draw a schematic diagram of this circuit.
(b) Labe the resistors R1 and R2. Place the mouse over each resistor and record the
resistance. R1 = ____Ω
R2 = _______Ω
(c) Use the ammeter to measure the current flowing through each resistor.
R1 = __________ A
R2 = __________ A
Circuit #7: Add a third green resistor in series to the above circuit.
(a) Draw the circuit.
(b) Record the new resistor’s resistance ____________Ω
What is the total resistance of the circuit?
(c) What does the ammeter read now? ____________ A
(d) Use the voltmeter to record the voltage at R1,R2, and R3. What is the total voltage?
Circuit #8: Connect a battery, an ammeter and a blue and a purple resistor in parallel.
(a) Draw the circuit.
(b) Label each resistor and record its resistance.
R1 = ________Ω
R2 = _________Ω
(c) Use an ammeter to measure the current through both resistors (A1 and A2). Clearly
mark on your diagram where you placed the ammeter. Use the ammeter to measure
the current through all the resistors in the circuit (A3), marking where you placed it
in the circuit. Record your current readings.
A1 = ______ A
A2 = _____ A
A3 = ______ A
(d) How do you find the total current in a parallel circuit?
Total voltage?
Circuit #9: add a third orange resistor to circuit #8.
(a) Record the resistance of resistor 3 ________Ω
(b) Draw the circuit.
(c) Use an ammeter to measure the current through each resistor. Also measure the
current through all resistors. Remember to mark where you put the ammeters on
the diagram.
A1 = ______ A
A2 = ______ A
A3 = _______ A
A4 = _______ A
Circuit #10: Connect a battery and 3 resistors in parallel: R1 (purple),R2(orange),R3(green)
(a) Draw the circuit
(b) Label the resistance of each resistor. R1= _______Ω R2=_________Ω R3=_________Ω
(c) Calculate the total resistance (hint: use Ohm’s Law)- show calculation
(d) Take ammeter readings across each resistor: (A1,A2 and A3)
A1 = ________ A
A2 = _______ A
A3 = __________ A
Mark the ammeter positions on your diagram.
(e) How could you calculate the total current? Show it here.
Now move the ammeter to take a reading of the total current. A4=______ A
Mark it on your diagram. Did this confirm your calculation?
Circuit #11:
(a) Click on the hand icon and select the section on building a combination circuit. Work
through it.
(b) Now build a circuit with 3 light bulbs in parallel and 2 more on the main branch.
Install switches so that 1,2 or all 3 pathways can be running. Draw your circuit.
(c) Measure the current in all 3 branches and before and after the battery. Label the
location of the ammeters on your diagram and record the readings beside them.
(d) Make a statement about current entering and leaving junction points.
Circuits #12 and #13:
(a) Click on the hand icon and select the short circuit section. Read through it. What
causes short circuits?
(b) Why are short circuits undesirable?
(c)Construct a series circuit with a short circuit. Draw it.
(c) Construct a parallel circuit with a short circuit. Draw it.
Circuit #14: Construct a circuit using all the components. Avoid short circuits. Draw it.