Series and parallel circuits

Lab 2: Series and Parallel Circuits

By Karim Berjaoui and Noah Sadighi

Submitted to Joanne Kettner

Lab Performed: 26-01-17

Lab Submitted: 9-02-17

Introduction

In this experiment, the properties of resistors where examined when they are connected in series and parallel. In addition, the definition of resistance (R = V/I) will be verified by comparing the results obtained of the resistance. In the first part of the experiment, the resistance was measured for RA and Rb on the ‘’T’’ circuit board and all three resistances on the ‘’Parallel’’ circuit board. Then, the circuit was connected using the resistor RB on the ‘’T’’ board as seen in figure 1. The potential energy (Delta V) and the current (I) were obtained for 6 different pairs of values by varying the source voltage. Hence, by plotting a graph of Voltage versus Current, the resistance of the resistor was obtained and compared to the initial resistance measured. The resistance obtained using LINEST are expected to agree within their uncertainty limits.

[pic 1]

Figure 1: The first circuit configuration

In the second part of the experiment, the equivalent resistance of two different circuits was measured by using the results obtained in the preliminary Measurements in part one. It was performed by setting up the circuit as shown in figure 2 and figure 3.

[pic 2]

 Figure 2: The second circuit configuration

[pic 3]

Figure 3: The third circuit configuration

Then, the power supply was connected to the fourth circuit as in figure 4. The total voltage and voltage across few points were measured and then compared with the source voltage of the circuit. The current across each resistor was then measured and also compared to the total measured current of the circuit. Finally, using the measured total current and the voltage across the circuit, the equivalent resistance was calculated and then compared to the previously measured one. As in the first part of the experiment, the calculated equivalent resistance was expected to fall within the uncertainty limits of the measured one. The sum of the measured potential difference across different points is expected to match within its uncertainty limit to the measured one of the power supply. Furthermore, the sum of the current in each wire of the parallel circuit is expected to match within its uncertainty limit the value of the total measured current of the circuit.

[pic 4]

  Figure 4: The fourth circuit configuration                        

Theory

An electric circuit forms a continuous path between the terminals of the source where resistors, in parallel or in series, are connected in the circuit by wires. There is a current (I) that passes through the wires, which is pushed because of the electric field that is created due to the potential energy in the wires. Ohm’s law explains this, where the current through a conductor is proportional to the potential difference between its ends.

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