Day 14 (Day16 on notes)

Today we learned a bit more about inductors and went over 1st order circuits. We also did a Passive RC Circuit Natural Response Lab and a Passive RL Circuit Natural Response Lab. 

Above we took a look at equivalent inductance that works like ohms laws for resistors.

We did a quick example of finding the time for a capacitor at 5V to drop to .01V which we see is about 6 seconds.

Passive RC Circuit Natural Response Lab:

The objective for this lab is to measure the response of a RC circuit when charging then manually disconnecting the power source to measure the voltage across the capacitor using an oscilloscope.

Above is our circuit set up for part b of the lab.

Part a) Here we have the capacitor fully charged at 3.5V then the voltage drop is recorded as the power source is shorted. The time constant is then measured by 36.8% of the fully charged voltage (1/e of the exponential curve).


Part b) Like in part a, we use the same method to calculate the time constant.

Above are the results we got for the lab. the large percent error in part b is expected because we were not able to switch the circuit manually fast enough to decrease error. Despite the lack of an efficient switch, we had expected to see a large uncertainty value in our results.

Above are examples of first order RL circuits. We were to find current and voltages as a function of time of the inductor and its time constant.

Passive RL Circuit Natural Response Lab.:
The purpose of this lab is to measure the response of a RL circuit and manually disconnecting the power source to measure the voltage across the inductor using an oscilloscope.

Since time in class was running out, the professor set up the circuit and displayed the oscilloscope measurements on the projector. We had made a prediction of the behavior of the voltage across the inductor (in green) with a square wave voltage input. The current (in blue) was then drawn based on the green graph.

Here is the voltage graph that was measured across the inductor which agrees with our predictions.


Here I included a table of equations from today's lecture.