magnetism

RC circuits

Today we examined how resistors and capacitors worked within a circuit. with a power source connected in series with a capacitor, and a light bulb we saw how the capacitor was able to charge or store energy within itself. we saw that when the power was initially turned on the light bulb was at max brightness and as time passed the light bulb dimmed until the capacitor was fully charged. when we discharged the capacitor we found that the discharge and the charge time were the same.



This is the set up of our capacitor in blue with a power supply and light bulb.

 

Then we evaluated the time it would take to charge two capacitors instead of one and we found that the time it took to charge was longer even though we predicted the time to be shorter. this makes sense because we are charging more capacitors making the charge time and discharge time longer.

This is the circuit we are going to set up inorder to measure the potential with respect to time using logger

electronics day 2

electronics day 1

 

 

 

 

 

 

Capacitance

For our capacitance experiment we tried to find a relationship between the surface area of the plates and the distance apart the capacitors are from each other. to do this we used aluminum squares and a book to vary the size and distance. first we used a small square and measured the capacitance between 1, 10, 20, and 50 sheets of paper to get a relationship between capacitance and distance.

This is the book and how we measured the capacitance between papers. when we put the aluminum between pages we had to create tabs that popped out of the edge to hook on to the alligator clips. the hard part was getting the aluminum to not touch.

 

These are the results from our experiment were we were able to solve for the constant k within our derived capacitance equation which we found to be 6.58

Using this data we input it into the excel

 

From the data from excel we created a graphical representation of our results were we saw a parabolic curve where the slope of the curve stands for the constant of k.

 

When you reverse a capacitor, with enough voltage you can get an explosive reaction that could harm you.

here we looked at the capacitors in series and in parallel and found that they are opposite that of the resistors. when capacitors are in parallel they are added together and when in series they are added inversely.

this is just some of the examples used in determining the capacitance of a circuit.

circuits

this is were we calculated the current flowing through the parallel circuit and derived a formula that showed the current in I1 is equivalent to the two connecting currents. 

This is the set up of our parallel circuit and what we used to measure current and resistance. 

This is the setup of our series circuit where the light bulbs are set up in series

This is our calculation for the current and resistance of a series and we found that the potential is equal to the sum of the potentials. we also found that the resistance is constant throughout the circuit. 

This is our table of how we analyzed resistors and used the colors on the resistors to unveil its identity. we noticed that some of the resistors have a lower uncertainty and would be more ideal for measurements requiring a higher precision of accuracy. 

This is the diagram of resistors that are set up like so and using this we calculated the total resistance. when we calculated the expected value of 52 ohms, we created the same circuit shown below and measured the resistance where we got an experimental value of 51 ohms. 

here we evaluated a circuit using loops law and kirkoffs law where we came up with 3 equations with 3 unknowns so that we could find the current through each wire. 

potential

The diagram of a point charge from a charged ring and on the right is an excel worksheet of us trying to determine the potential of the ring using sums of segments. then we moved the particle up to where it was parallel to the top of the ring and did the same thing. what we found was that the potential at this point is much higher than that at the center of the ring. this is because the potential from the bottom to the top of the ring is greater than from the center to the edges. 

we derived a formula for the potential of a point charge anywhere in the xy plane from the center of a finite bar. then we derived another formula for if the distance was from the point charge to any point on the bar. 

In this experiment we observed the potential difference between a point charge and a line. using a current of 12V we measured incrementally from the point toward the line. using this data found in the excel ws, we found a graph that did not fit our predictions. our potential vs distance is inversely proportional however the points deviated a lot from the fit curve. this could be due to the fluctuation of the current flowing through the paper.