Physics307L F09:People/Ozaksut/Notebook/070827

--Anne Ozaksut 00:28, 22 August 2007 (EDT) My Intro Info Oscilloscopes

Setup I plugged in the function generator and oscilloscope. I connected the HI voltage output on the function generator to channel 1 on the oscilloscope with a

AC Coupling 50 milliseconds using cursors/measure function Measure button calculates 60 milliseconds. This could be due to a difference in the points chosen to start the fall time. I manually chose 8V. The oscilloscope computer chose 7.44V, so because it decreases slower at low volts, the fall time between 7.44 and .74V is 60 milliseconds.

V(t)/V0=1/10=-e^(-60ns/T)

I got 52ms for the fall time when I used the cursors a second time with 2.5Hz and 12 Volts.

Oscilloscope Lab Summary
First, I became familiar with the function generator and the oscilloscope by choosing specific waves to output in the function generator, and measuring these known values on the oscilloscope using both my own senses (counting graph divisions and using cursors to visually determine quantities) and the computer (using the "measure" function on the oscilloscope to get an internal, more precise reading). Then, I learned how to detect a wave and take a snapshot of it by using the "triggering" function on the oscilloscope on different waves. Last, I compared AC and DC coupling with a DC current. I measured the fall time (time it takes for the function to drop from max V to 10% of max V) of the function with AC coupling using both methods from the first part of the lab. I measured a fall time of ~52ms. I lost my data at the end of the lab period, however, in order to calculate error bars, I would have taken my fall time measurements from both methods and found the Standard Deviation.

I learned that function generators allow us to specify the characteristics of the wave we want to study, and oscilloscopes visually represent EM waves on graphs whose parameters we can change depending on what we want to study, allowing us to take measurements of any wave we input into the machine. I reviewed mathematical qualities of a wave (increasing amplitude multiplies the function by a constant, and the DC offset adds a constant to the function). I was also (re?)introduced to coupling on a circuit diagram, and I learned how to actually use two pieces of equipment.

Useful additions to the lab might be EM review, a coupling concept review, and a description of oscilloscopes and function generators in layman's terms. However, we learn all this by the end of the lab anyway, and maybe we learn it better because we don't know what's going on ahead of time. I didn't find the Wiki articles very helpful.