Kirchhoff's Rules and Capacitors

The day began with a quiz about Kirchhoff's rules and we solved the problem as a class. We began by finding the the current between the two loops in the parallel circuit. We then found that the negative current of the bottom lop plus the current of the top loop is equal to the total current around the whole circuit. Using those equations we were able to solve for the voltage through the top and bottom lop as well as the power of the top and bottom loop. The results are shown below.

We then moved on the topic of capacitors. Capacitors are devices that store electrical charge and electrical potential energy. Mason gave us a relationship between voltage, charge and capacitance which was Q=CV. We were also derive that further by using the definition for charge and voltage into the equation C=kEA/d. We also did our own experiment were we created our own capacitor using two sheets of tin foil in between pages of the lab manual. We recorded the capacitance in nF and drew a graph that compared the relationship between distance and capacitance and drew our conclusions that as distance increases, capacitance decreases.

Next we solved our problem using our new definition for capacitance in order to find the area of a given object. Then we began to learn about relationships between capacitance and circuits and how they behave in parallel and in series.

The capacitors behaved oppositely to the way resistors behaved. When capacitors are in series, the inverse of the total capacitance is equal to the total sum of the inverse of all the capacitors and when capacitors are in parallel, the total capacitance is equal to the sum of all the capacitors. Then, we solved a problem very similar to a resistor one we had.

Finally, we applied Kirchhoff's Rule to a closed circuit with capacitors. Using previous methods, we solved for the voltage across the whole circuit as well as the total energy.

Overall, we learned about capacitors and how to use them within a closed circuit and then we applied Kirchhoff's Rules to a closed circuit involving capacitors instead of resistors.