Physics307L:People/Harriger/Summaries/Lab 00

Summary
This lab covered the basic operation of the oscilloscope, a device which allows for measurements of varying voltages. We used a wave function generator, which generates a time varying electric signal, connected to the oscilloscope via a BNC cable, to create and analyze waves at different settings. The three wave types we could analyze were sine, square, and triangle waves. We used different ways to measure the amplitude and period of the waves: the measure function, the cursor, and counting the grid by hand.

Then we looked at a square wave with AC coupling and DC coupling. There is an AC and a DC signal from the function generator. AC coupling makes the signal go through a capacitor, which acts as a high pass filter and smooths away noise that is left in with the DC coupling. We measured the fall time associated with capacitor in the AC coupling with the measure function and using the cursors to isolate data points. The measure function on the oscilloscope gave the fall time as 37.1ms and we found the fall time to be 23.82ms based our calculations from the cursor measurements. In our work uncertainty was introduced by human error when taking measurements, truncation by the internal computer of the oscilloscope, and rounding error during calculation.


 * In this lab I worked with Brian P. Josey.


 * These are my Detailed Lab Notes.

Analysis
From the cursor measurements, the fall time, $$\tau$$, can be found using the equation: $$V(t)=V_0 e^{ \frac {-t} {\tau}} $$ From the square wave we measured the following values with the cursor: $$V_1=7.2V, V_2=4V, T_1= -35.2ms, T_2=-21.2ms $$ Using these values in this equation derived from the first: $$V_2=V_1 e^{ \frac {-|T_2-T_1|} {\tau}} $$ $$\tau$$ is determined to be 23.82ms. This is 64% of the oscilloscope's value.

Conclusion
Having never seen an oscilloscope or a function generator before, I learned a lot about how they work and how to use them. I also learned how to use the OpenWetware site to keep a detailed lab notebook with much help from Brian.