Oscilloscope Tutorial for EEL 4712 Students at University of Florida - Prof. Eric M. Schwa, Lab Reports of Electrical and Electronics Engineering

Download Oscilloscope Tutorial for EEL 4712 Students at University of Florida - Prof. Eric M. Schwa and more Lab Reports Electrical and Electronics Engineering in PDF only on Docsity! University of Florida EEL 4712 Drs. Herman Lam & Eric M. Schwartz Electrical & Computer Engineering Dept. Former TAs: Eric Siegel & Erik Sjolander Page 1/8 Revision 0 23-Aug-06 Oscilloscope Tutorial Starting Note: Assuming you have your 8-bit counter from lab 0 is programmed into your BTU board, with pin assignments for clock (i.e., it is an input and pulled out) and all output pins (Q0-Q7, RCO) are pulled out. All references to buttons correspond to the numbering system in the user’s manual pages 2-3 through 2- 7; please refer to them as necessary. Before you start Make sure all calibration knobs (the red ones) are turned into a locked position (clockwise with the arrow). No great force should be needed; you will hear/feel a click when it is locked. Default positions for knobs you don’t need to care about • Input coupling (#12), labeled “AC GND DC” o Set the switch to the right on DC. • Vertical Mode Switches (#14) o BW Limit – out o “Add Alt Chop” – set to Alt (middle) • Invert (#13) – pulled out • Horizontal Mode (#21) – Set to A (left) • “Var Holdoff” (#34) – sweep to norm (counter clockwise) • “P-PAuto” (#26) – Pushed in • “A Source” (#29) – Set to Int (Up) Procedure 1) Turn on the oscilloscope by pressing in the black square/power button (# 2). A Green LED will turn on. Note: Give the screen a few seconds to warm up. It is ready when you see one or two green horizontal lines. If you do not see anything after ten seconds please consult the trouble shooting section of this tutorial. 2) We will start by using only the Ch 1 probe. In the VERTICAL MODE box (#14) set the left most switch to CH1 (all the way left). 3) Connect the ground clip (the alligator clip on the short wire) for Ch 1 to the ground pin on your BTU board. 4) Connect the probe tip to the output pin that Q3 (the MSB) has been assigned to. Hopefully you see something on the screen that isn’t just a horizontal line. Note: Make sure the red slider on the probe is set to “x1” 5) CH 1 Volts/DIV (#9) should be set to 1 Volt per division. Since we are using the x1 magnification on the probe, move the 1 on the dial to the 1x bracket labeled on the oscope. 6) Look at the A and B SEC/DIV (#19) knob. Find the nub sticking out which is in between the two black lines on the clear dial. This your time base indicator, now turn it to .5 us (micro) University of Florida EEL 4712 Drs. Herman Lam & Eric M. Schwartz Electrical & Computer Engineering Dept. Former TAs: Eric Siegel & Erik Sjolander Page 2/8 Revision 0 23-Aug-06 Oscilloscope Tutorial NOTE: Pulling out the red calibration knob here will result in a 10x magnification (so that will divide your time base by ten, going from .5us to .05us=50ns). Only use this when needed because it will dim the display, so keep it in for now. 7) Now on screen you should see around eight periods of a square wave. Congratulations! 8) Time to get familiar with some other important components. Take a few moments to experiment with knobs vertical position (#15), horizontal position (#24), CH 1 Volts/DIV (#9), and A and B SEC/DIV (#19). What do these knobs do, besides turn? 9) Set CH 1 Volts/DIV (#9) to 1, and A and B SEC/DIV (#19) to .5us. 10) Since you know how to do this now, move the square wave into the upper right quadrant of the display. Brief Note on triggering: As you hopefully know, an oscilloscope displays a measurement of Voltage vs. Time (vertical and horizontal respectively). A trigger is comprised of a voltage (i.e. 3V, 5V, GND) and a direction (i.e. rising or falling). The scope waits for a trigger to occur before it refreshes the screen. 11) Locate the trigger slope button (#28). This sets the direction of the trigger. When you push this button what happens? Why do you think this occurs? Seriously think about it! 12) Now it’s time for you to go solo and add the clock signal to the display. Start this by setting the VERTICAL MODE box’s (#14) left most switch to “BOTH” (in the middle). Another horizontal green line should appear. 13) Repeat steps 3-6 for channel two, thus adding the clock signal below Q3. Hint: You will have to use a different setting for your time base. Trouble Shooting Q: ACK! I can’t see anything on my display… it must be busted! A: No the scope is probably older than you…. It’s just fine. Here are some quick scenarios to help speed you along: • Is the power LED on? If not check both ends of the power cable • Fiddle with the o Vertical Position knobs (#15). o Intensity (#8), the fatter part of the knob. • Check that Horizontal Mode (#21) is set to A. • Is the trigger LED (labeled as “TRIG’D”) on or blinking? If not then: o Check that the “P-P Auto” (#25) is pushed in o Fiddle with the Trigger LEVEL Knob (#27) o Is “A Source” (#29) set to “INT” (up)? o Is “A&B INT” (#30) set to the trigger channel? • Push in the Beam Find button (#6). Draw by hand or take a picture of at least one period of Q3 and all corresponding clock periods. Show this to your TA. University of Florida EEL 4712 Drs. Herman Lam & Eric M. Schwartz Electrical & Computer Engineering Dept. Former TAs: Eric Siegel & Erik Sjolander Page 5/8 Revision 0 23-Aug-06 Oscilloscope Tutorial University of Florida EEL 4712 Drs. Herman Lam & Eric M. Schwartz Electrical & Computer Engineering Dept. Former TAs: Eric Siegel & Erik Sjolander Page 6/8 Revision 0 23-Aug-06 Oscilloscope Tutorial University of Florida EEL 4712 Drs. Herman Lam & Eric M. Schwartz Electrical & Computer Engineering Dept. Former TAs: Eric Siegel & Erik Sjolander Page 7/8 Revision 0 23-Aug-06 Oscilloscope Tutorial