Day 13

In this assignment, we will measure the relationship between the voltage difference across a capacitor and the current passing through it. We will apply several types of time-varying signals to a series combination of a resistor and a capacitor. The voltage difference across the resistor, in conjunction with Ohm’s law, will provide an estimate of the current through the capacitor. This current can be related to the voltage difference across the capacitor.

Pre-lab: understand circuit and draw pictures. 

Here is our predicted graph.

before the lab, we calculate the R and C

The Rand C are measured:  

                                         R                          C

theoretical values:       100 ohm                1 uF

experiment value:       100.1 ohm            1.096 uF

breadboard is set up.

Measure the wave after we apply three different frequency AC.

First: A sine and amplitude 2V with 1kHz is applied.

Second: A sine and amplitude 2V with 2kHz is applied.

Third: A sine and amplitude 4V with 100Hz is applied.

Analysis: 

after we got picture, our analysis are almost right. the formal I=V/R is used to get current. Then we found, the capacitor has a right angle phase shift. And we can know the V is between middle line to top or bot value.

Summary:

Today we learned capacitors and inductor. When we calculate the capacitor with series, its calculation way is same with parallel about resistance. When the capacitor is parallel, we calculate it with adding.
We calculate inductor, it is same way with resistance.