ECE 110 Final Exam Review Session

1. ECE 110 Final Exam Review Session Slides By: Corey Snyder Presented by: Steven Kolaczkowski

2. Before we get started… • We have additional office hours this week • Don’t forget about HKN • You get a cheat sheet! • 1 8.5x11” two-sided

3. Circuit Analysis Basics • Ohm’s Law: V = IR • Kirchhoff’s Voltage Law (KVL): • Sum of voltage rises = Sum of voltage drops in a closed loop • Kirchhoff’s Current Law (KCL): • Sum of currents entering the node = Sum of currents exiting the node • Resistors in series versus resistors in parallel • Series -> Same current • Parallel -> Same node voltages

4. Power and Labeling • P = IV • Can find other forms using Ohm’s Law • With standard labeling, current goes from + to – • P = IV • V = IR • With non-standard labeling, current goes from – to + • P = -IV • V = -IR

5. Thevenin and Norton Equivalents • Three parameters to figure out • IN = ISC • VT = VOC • RT = RT = Reff • Load Line

6. Node Voltage Method • Combination of KCL and Ohm’s Law • Be careful of current directions • Utilize supernode when there is a floating voltage source

7. Diodes and their Applications • Remember the basic operation of a diode • Large-Signal Model • Rectifiers • Used in AC/DC converters (ECE 343!) • Clipper circuits • Useful to check extreme values for input

8. Bipolar Junction Transistor (BJT) • Three terminal device: Base, collector, emitter • VBE,ON and VCE,SAT are properties of the BJT (ECE 340!) • In ECE 110 we consider the Common-Emitter (CE) configuration • For more on this, take ECE 342! • Three regions of operation: Off (Cutoff), Active, Saturation • Off: VBE < VBE,ON , all currents are zero! • Active: VBE > VBE,ON , • Saturation: VBE > VBE,ON , VCE = VCE,SAT , !

9. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) • Three terminal device: gate, source, drain • Comes in two flavors, NMOS and PMOS, more on this in the next slide! • VTH is a property of the specific MOSFET (hello again ECE 340) • Be comfortable interpreting I-V Characteristic of MOSFET

10. Complementary MOS Logic (cMOS) • Combine NMOS and PMOS transistors in order to perform a logical operation • i.e. AND, NOR, NOT • NMOS and PMOS are biased differently • NMOS, source connects to ground; PMOS, source connects to VDD

11. Intro to Digital Signal Processing • Sampling • Nyquist Criterion • fs > 2fmax • Quantization • Can encode 2N levels for N bits • Round to nearest level • Data Conversion • Amount of data in a song, etc. • Take ECE 310!

12. Compression and Huffman Encoding • Savings = 1 – 1/DCR • Huffman Encoding • Pick two least frequent elements • Pair these elements, pick a standard (bigger on the left or right) • Eliminate paired elements, replace with new combined node • Repeat 1-4 until you reach root node (sum is 1) • Label left branches 1’s, right branches 0’s (technically the opposite works too, again be consistent!)

13. Solar Cells and Photodiodes • Solar cells are used to turn solar energy into electrical energy • You are not expected to understand the underlying device physics. Instead, understand the following relations • Photons are absorbed only if their energy is greater than or equal to the bandgap energy • Photodiodes have different and for different levels of illumination

14. Lessons to Lend to a Friend for the End (of the semester) • Don’t spend too much time on questions you can’t do • Spend your time showing what you know • Pace yourself! • Take some time to relax before the exam

15. Diode Example – How many are on? • In the following circuit, How many diodes are on?

16. Diode Example – Clipper Circuit • For the following clipper circuit, determine the minimum and maximum output voltages.

17. MOSFET Example – IV Characteristic • The I-V Characteristic of a MOSFET is shown at right. , and . • What is ? • What is ?

18. MOSFET Example – CMOS # 1 • Fill in the following truth table for the provided cMOS circuit.

19. MOSFET Example – CMOS #2 • What input combination will result in an improper output for ? • 000 • 111 • 011 • 110 • 101

20. SNR Example • A sinusoidal signal is measured across a resistor. If the sinusoidal signal component is given by what rms noise voltage must also be present to give a signal-to-noise ratio of 8?

21. Quantization Example • What is the minimum number of bits per sample needed to digitize a 0 to 8 volt signal if the quantization error (half of the level spacing) should be less than 0.2 volts?

22. Entropy and Compression Example • Consider the set of symbols with probabilities . • If we were to use the same number of bits per symbol for all symbols in this set, how many bits would we need for each symbol? • What is the entropy of this symbol set?

23. Huffman Coding Example • Suppose we have a collection of symbols with the following frequencies. • A = 14 • B = 7 • C = 6 • D = 4 • E = 3 • F = 2 Form the corresponding Huffman Tree and Huffman Code