Series Parallel Lab Report

Series and Parallel Circuits Mitch Gramazio

Purpose: To study current flow, voltage, and resistance in series and parallel circuits. Materials: • (1) Circuit Board w/ accompanying wires • Varying Resistors • (2) 10 Ω Resistors • (2) 51 Ω Resistors • (2) 68 Ω Resistors • (3) Lightbulbs • (1) Power Supply of 3V • (1) Voltmeter • (1) Ammeter • (1) CBL w/ TI-84 Calculator Data: Tolerance and Resistance Resistors

Tolerance

Minimum Resistance

Maximum Resistance

10 Ω

5.00%

9.975 Ω

10.5 Ω

51 Ω

5.00%

48.45 Ω

53.55 Ω

68 Ω

5.00%

64.6 Ω

71.4 Ω

Series Resistance, Voltage, and Current

Resistor 1 1 10 Ω 2 10 Ω 3 51 Ω

Resistor 2

Current

10 Ω 51 Ω 51 Ω

0.151 A 0.050 A 0.031 A

Voltage 1 1.41 V 0.46 V 1.45 V

Voltage 2 1.41 V 2.42 V 1.45 V

Total Resistance 18.68 Ω 57.60 Ω 93.55 Ω

Total Voltage 2.98 V 2.88 V 2.91 V

Parallel Resistance, Voltage, and Current

Resistor 1 1 51 Ω 2 51 Ω 3 68 Ω

Resistor 2

Current

51 Ω 68 Ω 68 Ω

0.059 A 0.044 A 0.045 A

Voltage 1 2.82 V 2.83 V 2.84 V

Voltage 2 2.81 V 2.82 V 2.83 V

Total Resistance 23.90 Ω 32.10 Ω 31.50 Ω

Total Voltage 2.83 2.83 2.85

Current Flow in Series and Parallel Circuits

Series Parallel

Resistance 1

Resistance 2

Current 1

Current 2

10 Ω 51 Ω

51 Ω 68 Ω

0.050 A 0.060 A

0.050 A 0.045 A

Series/Parallel Resistance, Voltage, and Current with Lightbulbs Series VoltageTotal = 2.87 V CurrentTotal = 0.074 A ResistanceTotal = 36.49 Ω Resistance

Voltage

Current

First Bulb

12.973 Ω

0.96 V

0.074 A

Second Bulb

12.027 Ω

0.89 V

0.074 A

Third Bulb

11.486 Ω

0.85 V

0.074 A

Parallel VoltageTotal = 2.80 V CurrentTotal = 0.612 A ResistanceTotal = 4.58 Ω Resistance

Voltage

Current

First Bulb

12.91 Ω

2.44 V

0.189 A

Second Bulb

12.12 Ω

2.46 V

0.203 A

Third Bulb

11.18 Ω

2.46 V

0.220 A

Results: Throughout this lab, we experimented with a circuit board which consisted of resistors and light bulbs. From the first part of the lab, we learned that, using pre-existing resistors (which had a certain tolerance level each), when connected in a series, the voltage before and after each resistor adds up to the total voltage. In a series, the current before and after each resistor is the same. Also in a series, the resistances add up. However, in a parallel circuit, the voltage before and after each resistor is the same. The currents before and after each resistor add up to the total current. The inverse of the resistance is equal to the inverse of the resistances of each resistor. The same principle applies to light bulbs. However, for the the experiment with light bulbs, we did not know the resistance of each individual light bulb. Using mathematical equations and measuring carefully, we were able to find the individual resistance of each lightbulb, while proving that the same principles apply. During the lab, though, we experienced problems. The resistances in part 2 and 3 were supposed to be the same, but they were not. This might have been a cause of human error or tolerance. Analysis: 1.

2. 20 Ω, 60 Ω, 100 Ω 3.

4. 19.7 Ω, 57.6 Ω, 93.87 Ω (plus/minus 5% each given resistance) 5. 25 Ω, 28.8 Ω, 34 Ω 6. 7. 8. 9. 10. The one with the least resistance. V = I * R Conclusion: In conclusion, this lab has helped me to better understand how electric current, voltage, and resistance is affected by the circuit it is connected in. It has also helped me learn how to physically visualize and set up a parallel circuit which used to be hard for me to see. This lab has deepened my understanding on electricity.