Download Electric Circuit Lab

Electric Series Circuit Lab (100 points)
Warning: Do not touch any live wires or leads. Show your circuit to your teacher before
connecting the battery.
Materials:
power supply, board wires, voltmeter, ammeter, switches
Procedure:
connect the resistors in series, measure voltage and current
determine the resistance for each resistor with Ohm’s law
always connect the voltmeter in parallel, ammeter in series
draw circuit diagrams for series
Calculations:
R=V/I
P=VI
Procedure for Series Lab: Connect the given resistors in series. One 100 , one 250 . Measure the
voltage across each resistor and the current in the circuit. Use a 6 V battery as your power source.
Before connecting the battery make sure to show your circuit to the teacher for approval. Circuit
correctly connected (10 points)
Use a switch in the circuit and after connecting the battery close the switch only for as long as you
need to note the ammeter and voltmeter readings.
Draw the circuit diagrams neatly, labeling your components fully.
After finishing put everything back in place, disconnect power supply (10 points)
Series Circuit Data (10 points)
Resistors
Theoretical
Resistance
()
Measured
Voltage
across each
resistor
V1
V2
2 series
350 
Verify: (10 points)
The total resistance: R = R1 + R2
The total voltage in the circuit: VT = V1 + V2
Circuit + Diagram: (10 points)
Total
Voltage
on battery
(VT)
Measured
Current
I
(A)
Total
Resistance
R=VT/I
()
Power
(VT x I)
(W)
Procedure:
connect the resistors in parallel, measure voltage and current
determine the resistance for each resistor with Ohm’s law
always connect the voltmeter in parallel, ammeter in series
draw circuit diagrams for parallel
Calculations:
R=V/I
P=VI
Procedure: Connect the given resistors in parallel. One 250  and one 500 . Measure the voltage
across each resistor and the current in the circuit. Use the DC power supply as your power source
and carefully adjust reading to 6 V, DC. Before connecting power supply, make sure to show your
circuit to the teacher for approval. Use a switch in the circuit and close the switch only for as long as
you need to note the ammeter and voltmeter readings.
Draw the circuit diagrams neatly in all three cases, labeling your components fully.
Parallel Circuit Data (10 points)
Resistors
Theoretical
Resistance
()
2 parallel
250 ,
Measured
Voltage
(V)
Measured
Current in
each
branch
(A)
I1 =
500 
Verify: (10 points)
The total current in the circuit: IT = I1 + I2
If the total resistance in the circuit: 1/R = 1/R1 + 1/R2
Circuit + Diagram: (10 points)
I2 =
Total
Current in
Circuit (IT)
(A)
Total
Resistance
R = V/IT)
()
Power
(V x IT)
(W)
Conclusions (20 points)
1. Which filament has more resistance, a 40 W or 100 W bulb?
2. A 40 W and 100 W bulb are connected in series. Which glows brighter?
3. A 40 W and 100 W bulb are connected in parallel. Which glows brighter?
4. As you add more resistances to a series circuit, what happens to the overall resistance and total
current in the circuit?
5. As you add more resistances to a parallel circuit, what happens to the overall resistance and
total current in the circuit?
6. Do lights use less energy in series or parallel circuits?
7. Are the lights in your home in series or parallel or a combination of both?
8. A 3-way bulb uses two filaments to generate the light. Are they connected in series or
parallel? Hint: The brightest light is always the sum of the two dimmer lights.(Example: 50W,
100W, 150W or 100W, 200W, 300W)
9. What safety devices are used in your house to prevent overloading?
10. Name any three precautions you should use when dealing with power supplies or probing
unknown circuits?