Download Lab Activity: Investigating Circuits with Multiple Resistors

Lab Activity: Investigating Circuits with Multiple Resistors
R2
1. Set up a circuit as shown.
Measure the current
through each resistor:
I1=
I2=
I3=
R1
battery
R3
a) What did you notice about the current through each resistor?
b) How does this compare to the current coming out of the battery?
c) DO RESISTORS ‘USE UP’ CURRENT?
2. Measure the voltage across the battery (total Voltage), and across each resistor.
Vtotal=
How does V total compare to V1 V2 and V3?
V1=
V2=
V3=
How does V total compare to V1 + V2 + V3?
The circuit above is said to have its resistors ‘in series’.
*
When in series, the current through each resistor is _______________.
When in series, Vtotal equals _________ of the voltages across each resistor.
*
Because of the relationships just stated, we can figure out how the total resistance is
related to the resistance of each individual resistor.
IN SERIES
RT =
Follow Up Activities for Both SERIES AND PARALLEL CIRCUITS
Take three resistors of the same order of magnitude and clip them together. Use the
meter to check and see if in fact the resistance of them together is what you predict (use
the color code).
Now predict V1, V2, V3, and IT for a VT of your choosing. Once the predictions are
complete, set the circuit up and test using the meter.
Remove R2. Note what happens to V1, V2, and IT by taking new measurements.
Rewire the circuit like this.
battery
Measure the voltage
across each resistor:
V1=
V2=
V3=
Now measure the
voltage across the
battery:
Vtotal =
R1
R2
R3
Resistors wired like this are said to be ‘in parallel’. The voltage across each is the same.
Measure the current
through each resistor:
Now measure the current
coming out of the battery:
I1=
I2=
I3=
Itotal=
*
When in parallel, the voltage across each resistor is _______________.
When in parallel, Itotal equals ________ of the currents through each resistor.
*
Because of the relationships just stated, we can figure out how the total resistance is
related to the resistance of each individual resistor.
IN PARALLEL
1
--- =
RT
Take two or three resistors and clip them together. Use the meter to check and see if in
fact the resistance of them together is what you predict (use the color code).