User:Joseph Frye/Notebook/Physics Junior Lab 307L/Oscilloscope
Oscilloscope Lab
SJK 16:20, 24 September 2010 (EDT)
This is a good primary notebook, but in general it's a little sparse. I tried to find your notes for the neon lab, but can't see any yet. So, I'm guessing you're taking notes with another application. I'm hoping they're a bit more detailed than these, especially since you and Alex broke ground on that experiment.
I did this lab on Mondays August 23 and 30 2010 with Alex Benedict at UNM. We were following this assignment from Dr. Koch: Physics307L:Labs/Oscilloscope
Links
Alex Benedict's notebook from this lab
Equipment
Tektronic TDS 1002 oscilloscope BK Precision 4017A 10 MHz function generator
SJK 16:00, 24 September 2010 (EDT)
Good that you list equipment make and model numbers. Pictures would allow for easy description of connections.
Set up
We put the oscilloscope on top of the function generator and connected them using BNC cables
Measurements
We measured the peak-to-peak voltage as well as the period of some different sine waves. We did this using 3 different methods. We first measured using the grid on the oscilloscope screen. We measured using the cursors on the oscilloscope. We also measured using the "measure" function on the oscilloscope. Our data is below and these measurements are on 'sheet1'.
We also measured the fall time of a square wave with a DC offset and AC coupling on. This set up causes the voltage to droop. The fall time is how long it takes the voltage to fall to 90% of its total drop. SJK 16:17, 24 September 2010 (EDT)
fall time should be how long it takes to fall 90% from it's peak. So, if your signal started at 10V, it's the time it takes to get to 1 V, regardless of whether it reaches 1V before switching polarity. I think this misinterpretation may be why your fall time data varies with input frequency. Also, the use of spreadsheet is great. You should also point out the results in your primary notebook here. So the reader doesn't have to deduce what are the final results by himself.
We measured this using the cursors as well as the "measure" function on the oscilloscope. This data is on 'sheet2'
Model numbers for our equipment and additional note are in the 'Notes' tab
{{#widget:Google Spreadsheet |key=0AsLE8iWrtjlSdFdsNkhhSGFzcUZlY0ZTcHpLaEpmTkE |width=1150 |height=400 }}
Observations
The oscilloscope could not measure low frequencies very well. For frequencies of about 10Hz or lower the scope displayed the frequency as "?10Hz". On the back of the oscilloscope we found that it is rated for "45-440Hz for 100-120V" and "44-66Hz for 120-240V". This was consistent wit hour finding because we found that the oscilloscope also could not measure when we had a large DC offset of about 150V SJK 16:14, 24 September 2010 (EDT)
note copied from Alex page: Are you sure these ranges refer to the oscilloscopes ability to measure input signals? I think these ranges are the acceptable range of power supplies. For example the roughly 60 Hz, 120V outlet you used. For sure, the scope can measure input signals much higher than 440Hz
We also had time to use the x-y function on the oscilloscope. We hooked up a second function generator to channel 2 on the oscilloscope and were able to make some interesting patterns by varying the functions on the different channels.
