Lab Report Day 25 - Alternating Circuits

Resistors in an Alternating Circuit 

When studying a resistor in an alternating circuit, it is connected with a function generator and multimeter (measuring current) in series. We also attach a resistor with a voltage meter. 

This is the set up of the lab.

Our LoggerPro Data.

We then get the graph a Potential vs. Time, Current vs. Time, and Potential vs. Current. 

Our result and percent difference.

To calculate the theoretical Irms and Vrms, the Imax and Vmax we get from the LoggerPro graphs and divided by square root 2. Using those values, we calculate the percent difference of voltage and current. 

Capacitors in an Alternating Circuit 

When studying a capacitor in an alternating circuit, we use same set up from the resistor one expect that we replace the resistor with a capacitor. In AC circuits, capacitors exhibit a resistance. This resistance/reactance is given by Xc= 1/(Omega)C where omega=2πf.

Lab Set Up

Our data from LoggerPro

We get data from LoggerPro. The Vmax and Imax were taken from the graphs and used in order to find the Vrms and Irms. 

Using the formula for reactance, the theoretical and experimental values are found and the percent difference is calculated. 

Inductors in an Alternating Circuit

For studying inductors in an alternating circuit, the same set up is used while replacing capacitor with an inductor. Using data from LoggerPro graphs, calculation of Vrms, Irms, and Xl, the experimental resistance of the inductor is calculated and the theoretical inductance is found with a volt meter. The percent difference is found to be 149.6%.

Lab Set Up (Right Side)

LoggerPro Data

Results Table

For the second part, we put a iron core and do the same steps from part 1. In the end, a 77% difference is calculated, a much lower percent difference than without the iron core. This is due to the iron core increasing the inductance without changing the resistance. 

RC Circuits

For the final part of the lab, we study a RC cirtuit. A resistor and a capacitor are connected to a function generator and a current meter and volt meter with to LoggerPro. Using the graphs the Vmax and Imax are found and so are the Vrms and Irms. The total resistance within the circuit is the total impedance, or Z. 

Lab Set Up

LoggerPro Data

The percent difference is found for the impedance as well as for the time phase change. Once again, using the values from the graph, The time difference for a period was found and divided by the period, 1/frequency. 

Summary: 
Today, we talk about an AC circuit again. In AC circuit, the voltage and current varies in a sine function. We quickly reviewed DC and AC circuit and then defined formulas for I,V, Irms, Vrms, and Pavg in an AC circuit. We learn some property of resistor, capacitor, and inductor.