# 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
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.
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 .1 = (exp( − t / s)) 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)