User:Daniel T Young/Notebook/Junior Lab 307L/2008/09/10

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Setup
Connected BNC to the function generator and Oscilloscope. Used auto set button to get a good view of my wave and changed function from the square wave to sin wave. After setting Frequency to 200 Hertz on the Wave function generator I found that my sin wave has gotten thinner so I adjusted the horizontal using the knob labeled position with arrows pointing up and down.

Using measurement button I view that all measurements are based off of Channel one while I am connected through channel 2. I change all measurement boxes so that they read the Frequency, period and Peak to peak. Here is how they read.

Basic waveform measurement
Reading One: Frequency- 200.5 ± 0.5 Hz  Period- 5±.02 ms    Pk-Pk= 224V (discovered that 10x multiplier was on giving actual pk-pk voltage of 22.4)

and we know that Pk-pk/2= Amplitude= 112V=Voltage from Function Generator (actual amplitude=11.2V)

Changed function generator values a bit. Output level set to about half original value. Frequency set to 100 Hz

Reading Two Frequency=100.6 ± 0.1Hz Period- 3±.05 ms   Pk-Pk= 11.6 (therefore Amplitude is 5.8V)

Changed output to about half of that from reading two. Frequncy set to 1000Hz.

Reading three Frequency=1000 ± 2Hz Period- 1±.002 ms   Pk-Pk= 5.64V (therefore Amplitude is 2.82V)

Triggering
Checking the triggering menu found that edge is the most applicable for DC currents. Triggering is a useful way to explore a wave when we have high time resolution. Also, depending on the triggering setting we can start the oscilloscope reading on the fall of the rising part of our wave which is helpful for viewing half a period for measurement of amplitude or time using cursors as we will explore later in the lab.

AC Coupling
Set the Amplitude/Voltage to 8.6 Volts and turned off DC offset. Also we set function generator to square wave. At extremely low frequency and high DC input with AC coupling set we get a wave representing a repeating exponential decay.

Measurement 1

Using cursors - Cursor 1 200e-3 V  Cursor 2 22V

90% point = (22V-200e-3 V)*.9=19.62 10% point = (22V-200e-3 V)*.1=2.18 fall time= 47.2ms


 * $$V(t) = V_0(1-e^{-\frac{t}{\tau}})\quad\iff\quad\frac{V(t)}{V_0}=(1-e^{-\frac{t}{\tau}})$$

[Fall Time Equation taken from here]

Thanks to Dr. Koch's observations I realized that my equation for fall time was incorrect. The actual equation is K=-t./log(V./Vo) and so with the code corrected my actual value for K is      K =0.0228

Measurement 2

Using Measure command pk-pk=27.2±.2 27.2 / 2=Amplitude=volts=  13.6 ± .2V


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