Capacitors 4/21/2014

Got bummed by a surprise fiesta wahhh?!!?.... -__-"

Today it is about capacitors.  While the word capacitors may be intimidating, it basically is a device that stores charge similar to a battery.  It consists of parallel material that are tightly layered over each other to hold charge.

The type of capacitor that is of the most practical interest is the parallel plate capacitor

 Capacitors of various sizes, voltage, and capacitances....

Our Lab, we conducted an experiment by turning a book into a capacitor by using two sheets of aluminum foil separated by sheets of paper.

In this activity, first, we carefully cut two square pieces of aluminum foil and measured the area to be 0.0316 m^2 for each.  We then measured the thickness of a single page by averaging the measurement of the thickness of 280 pages. Dividing, a single sheet was approximately 6.357E-2 m.

We then connected a multimeter to the two sheets of foil using alligator clips. The positive end on one of the aluminum sheets and the negative end on the other. We measured the capacitance with the multimeter as the foils were separated by 1 sheet of paper.  Next, we repeated this process for 2, 10, and 15 sheets of paper and recorded the capacitance of each run.

Finally, we folded the aluminum sheets to half of the original surface area (0.0158 m^2) and measured the capacitance again for 1, 2, 10, and 15 sheets of papers.

 There are two sheets of aluminum foil of equal area inserted into the book with pages in between them. 

As we collect data for capacitance, we pressed down on the pages to minimize separation distance.  We need to minimize any air pockets to only account for the thickness of the paper sheets.  Any unwanted separation distance accounted for will cause greater inaccuracy.

Data collected per separation distance from trials

We took the data and plot the points using Excel to fit the equations. The blue curve represents the data taken from the original foil surface area and the orange curve represents to the halved of the original surface area.

Data as Capacitance vs. Separation Distance graph 

NEXT, WE BLEW UP A CAPACITOR!! WOOHOO~

Eye protection required!

After math debris poor little capacitor LOL

Next, we attempted circuitry using capacitors like we did using resistors.  We placed the capacitors in both series and in parallel then measured the voltage to determine a relationship between the configuration.

Capacitors in parallel (left) v.s. in series (Dez working in progress) (right)

Given the  two capacitors. The final capacitance we were able to observe that in parallel the capacitance of the capacitors was simply the sum of their respective capacitance.  On the other hand, when hooked up in series, the capacitance of the capacitors add up inversely:

Unlike resistors, the capacitors shows an exact opposite relationship as to resistors.In series 1/Ctot=1/C1+1/C2.  In parallel 1 Ctot=C1+C2.  

Look what Prof Mason brought out..... a bucket?  noooo, a capacitor!  This liquid capacitor is filled with PCBs a highly energy-concentrated but yet, TOXIC substance.

 DAAAAAANG!! LIKE A BOSS!!!

We ended class with a La Puente waste dump lesson:

Apparently they dumped 3.4 million gallons of PCBs in the 60s-80s at the BKK landfill.  RUN STEPHANIE RUNNN!!