lecture 1: basics Oscilloscope & SPICE Basics

Lecture outline Course Goals/Outline The Oscilloscope P-SPICE Download Basic Circuits Lab Exercise Reading: 1.TDS200 manual pp EIL pp SPICE Ch. 1&2

course outline C1W8/25/10Scope Usage & SPICE C2W9/1/10Scope Usage & SPICE-Computer Lab C3W9/8/10Scope Usage & SPICE C4W9/15/10Op-Amp Characteristics C5W9/22/10Op-Amp Characteristics C6W9/29/10Timing & Pulse Circuits C7W10/6/10TIming & Pulse Circuits C8W10/13/10Audio-Amplifier C9W10/20/10Audio-Amplifier C10W10/27/10DC-DC Converter C11W11/3/10DC-DC Converter C12W11/10/10Signal Generator C13W11/17/10Signal Generator C14W11/24/10Active Linear Filters C15W12/1/10Active Linear Filters Learning by doing Laboratory exercises will frame the subject matter Integrated Approach Experimental, simulation and theory

grading Lab Demonstrations -30% Prelab & Demo Lab Reports & Lab Notebook -30% Notebook is like 1 report Exams-30% In-class or take home In-class quizzes-10% Surprise quizzes Recitation attendance is mandatory Grade penalty in syllabus

course goals 1.Look at a schematic of an analog circuit and qualitatively predict what the circuit does. 2.Use P-SPICE to perform detailed analysis of the circuit 3.Do back-of-the-envelope calculations to analyze the circuit 4.Derive the transfer function of a simple circuit with emphasis on amplifiers-frequency response. 5.Sketch Bode plots of this circuit 6. learn how to write proper lab reports

Lab reports Introduction Theory Experimental Results / Discussion Conclusions References

Introduction The introduction is exactly what it says. It is a paragraph or series of paragraphs that introduce the reader to the subject The introduction presents basic background material, the history of the problem, or introduces most of the major references Provide a schematic as well Use formal language. A conversational style is NOT acceptable (see example of tech memo)

Theory (or background) Explains the theory behind the work and is the proper place for the mathematics Contains the general equations that describe the system under study

experimental Explanations for the apparatus, instruments, calibrations, etc. Expected error and repeatability can be introduced Describe what you did in the simplest way possible Diagrams are always helpful

Results/discussion All results of the lab activity are reported here This includes simulation and experimental results Appropriate tabular and graphical form should be used All x-axis and y-axis scales should be clearly indicated (e.g., current probe measurements y-axis scale) along with UNITS!!! It is encouraged that you mark the scope captures with a pen showing relevant features or noting numerical values of significance. It is understood that for a formal report you would use some kind of CAD program to mark the figures

results/discussion All results should be discussed and compared with theoretical predictions and simulation results Discrepancies should be noted and an attempt to explain them should be made Are these the results you expect? Why? Do you notice discrepancies? What is causing these?

conclusion The conclusions should be a specific and factual summary of the report The conclusions should tie-up loose ends from the previous portions of the report such as speculation and questions, and analysis of the error.

rubric for lab report

the oscilloscope Oscilloscope displays voltages visually Coupling-AC, DC and GND Triggering-tells scope when to start displaying Analysis & Measurement utilities In the old days was all-analog Nowadays digital

analog o-scope Like a TV in many ways.

subsystems Display-analog or digital, LCD, CRT etc. Time-base, x-axis control-Trigger-int. or ext. Signal, Y-axis control-input, coupling Power supplies-fuses etc. Probes 1x, 10x etc. attenuation amount Calibration circuits -compensate input R, C

triggering Triggering allows the oscilloscope to be in sync with the signal you’re displaying, so you have a nice steady image. f(signal)=Nf(trigger signal i.e. x-axis time sweep) N is an integer or a fraction.

Sampling Digital o-scopes are not continuous Each screen has a fixed # of samples How many for TDS200? Smapling rate changes with time base If sampling is too little, aliasing can occur Like wheel turning backward in car commercials What determines minimum required sampling?

triggering Can be made to be one-shot to capture single events. How can you do this? This will be the exercise for the first lab capture a manual switch event.

ORCAD P-spice SPICE is a circuit simulation program-industry standard You create a circuit different circuit editors Then you simulate it! Gives you currents, voltages, transients etc. Download student version on your own computer lab.com/downloads/schematic/013/

P-SPICE TIPS Need a ground! ONLY use the “0” source in power sources Make sure you add the required libraries There are 3 ways to simulate Text editor ORCAD Capture ORCAD Schematic

p-spice Resources k This is for Capture The download page also has many resources I will post a SPICE reference also.

work through prelab Switch debouncer