# Physics307L F08:People/Gooden/Notebook/070827

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__see comment__## Contents

## 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__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__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 usFailed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://api.formulasearchengine.com/v1/":): {\displaystyle .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__## 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)