Download Series Circuit Lab

Parallel Circuit Lab
Name_______________________________
Objective: The objective of this lab is to able to calculate and measure equivalence resistance, current, and voltage drops across
electrical devices connected in parrallel.
Materials: Multimeter, 5 alligator ended connecting wires, 9 V battery
Use your multimeter to get the actual resistance.
3 Resistors: R1 = Grey Red Brown Gold = ____________Ω
R2 = Blue Grey Brown Gold = _______________ Ω
R3 = Brown Red Red Gold = ____________ Ω
Procedure:
1. Construct the circuit shown at the right.
2. Measure the voltage of your 9V battery. Make sure your multimeter’s probes
are plugged into the correct holes and the dial is set to the proper setting.
Vbattery = ____________
2.5. Calculate the theoretical total current flowing through the circuit using V = IR and
what you know about equivalence resistance.
1
1
1
1
 

 
RT R1 R2 R3
Toatal current = ____________
3. Close the switch and activate the circuit. Measure the voltage across R1, R2, and R3 with your multimeter. Make sure your red
lead is connected to the positive side of your resistor. You will know you’ve measured correctly because you’ll have
a positive voltage. See the schematic on how to measure.
VR1 = _______________
VR2 = _______________
VR3 = _______________
4. What is the relationship between the voltage drop across the battery and the
voltage drops across the resistors?
Calculate the theoretical reading that A1, A2, A3, and A4 will read.
A1 = _______________ A2 = _______________
A3 = _______________
A4 = _______________
5. Switch the settings on your multimeter to measure mA. Insert your meter into
the circuit at each spot of your circuit at right and record the current reading.
A1 = ___________
A2 = ____________
A3 = ____________
A4 = ___________
6. What is the relationship between all the current readings throughout your circuit?
6.5 Why do you think the current you measured isn’t exactly the current you predicted would flow through the circuit?
7. Find the equivalence resistance of R1, R2, and R3. We’ll call this value R equivalence, or the equivalence resistance.
Requivalence. = _______________
8. Go to the box of resistors and find the resistor that is equal to
the equivalence resistance. Construct this new circuit.
9. Measure the voltage drop across Requivalence.
VR equivalence = _______________
10. What do you notice about the voltage drop across the equivalent resistor? Is it
similar to any other voltage you’ve measured?
11. Measure the current running through the circuit.
Aequivalence = _______________
12. What do you notice about the equivalence current? Is it similar to any other current you’ve measured?