Physics307L:People/Gooden/Notebook/070827

see comment

Steven J. Koch 00:52, 29 August 2007 (EDT):Overall, excellent lab notebook!

set up

I set up the oscilloscope with a BNC cable to ch1 connecting to the low output of the generator. Generator producing sine waves at ~50 Hz. Set on DC coupling.

ch1 positioned at v=0. Trigger set at v=0, slope-rising.

Measurements

Measurement- Voltage with original wave

    1. using the grid to measure amplitude  
       of the wave I get ~4.4 volts.
    2. using the cursor mode I find an      
       amplitude of ~4.64 volts.
    3. Using the measure control I again   
       find an amplitude of ~4.64 volts. 

    REPEATS:making voltage measurements using the measure 
    and cursor controls for waves of different 
    applitudes and 20 and 30 hz.
    1. 20hz wave, I find 2.72 volts after   
       adjusting the amplitude.
    2. 30 hz with another adjusted amplitude I find
       1.36 volts as the amplitude.

Measurements- frequency - original wave (f=1/T)

    1. Grid- I find period of ~20ms and so for frequency I find ~50hz
    2. Cursor- I find a frequency of ~50Hz
    3. Measure control- I find a frequency of ~49.50 Hz

    REPEATS:making frequency measurements using the measure 
    and cursor controls for waves of 2.4v 
    applitudes and 30 hz.
    1. Cursor- 30.6 Hz
    2. Measure control- I find 30.6 Hz

       * Trying these functions for different types of waveforms
        (square wave, etc) to measure frequency and amplitude
        the oscilloscope seems to do so properly.*
      **Dr. Koch helped to explain calculate frequency from period and to use the
        functions on the oscilloscope**

Triggering

see comment

Steven J. Koch 00:44, 29 August 2007 (EDT):Great description!

   A) What does triggering on the rising edge mean?
       - this means that the trigger is set at a specified voltage on the 
         oscilloscope,and when the waveform reaches that value and is increasing, 
         event is registered.

AC Coupling

see comment

Steven J. Koch 00:51, 29 August 2007 (EDT):Excellent work on the AC coupling and in particular the calculation of the RC constant. I couldn't find anything when I tried either, but Antonio did find an article that looked promising.

    A)Read the ac coupling article
    B)Getting a voltage of about 12V, and then looking at the AC coupling to shift the signal
      back to zero voltage, and then decreasing the sec/div and volts/div a distinct 
      but 'noisy' sine component appears. The amplitude of the wave is ~10mV and a frequency
      of ~50kHz.
    C)Measuring Fall time - cursor function
        1. Using 1.12 volt square wave, and measuring with the cursor command I find a 
           fall time of ~52ms
        2. 880mV square wave, I find ~52ms
    C) Measuring Fall time - Measure function
        1. 880mV square wave, I find ~50ms
        2. 1.12 V square wave, I find ~50ms
    D)To find the RC constant we can use the equations given to us in the wikipedia article
      on the lab outline. The equation gives us [math]\displaystyle{ .1=(exp(-t/s)) }[/math] where t is the
      fall off time calculated previously and s is the RC constant. Solving this equation I   
      find s=22.5 milli sec.
    E)I was unable to find any information on the RC constant that I should expect on 
      the internet.

    ** Had help from TA in calculating the RC constant, and from Dr. Koch in using the 
       correct equation to do so.**

see comment

Steven J. Koch 00:51, 29 August 2007 (EDT):Great work giving credit!

FFT

    1)Using the FFT math function to find the frequency of a sine wave and with help from Zane
      Gibson, I find the frequency is 80Hz. Which matches up with what the wave generator is
      producing.
    2)