ELEC 226, Exam 1

Exam 1 will be on Tuesday, March 1, 2011.

• The exam will be closed-book and closed-notes, but you should bring your calculator and one piece of 8.5" by 11" paper with notes and formulas (you can write on both sides of the paper).
• If an exam problem requires Wye-Delta transformation, I will provide the Wye-Delta diagrams and formulas (so you don't have to include them on your paper).
• I will also provide the LP, BP, and HP filter equations from Homework 3 if they are needed in a problem (so you don't have to include them on your paper).

The topics will include everything we have done in class and labs through Thursday, Feb. 24, excluding the new material on inductance, mutual inductance, and transformers. A list of topics is included below, and this material is contained in Chapters 7, 8, and 9 of the textbook.

• Relationship between sinusoidal signals and phasors, and why phasors are useful
• Impedance, Ohm's Law with phasors & impedance, equivalent impedances (series, parallel, and Wye-Delta)
• Circuit analysis in the phasor domain (and converting back to the time domain for the final answer)
• Thevenin equivalent circuit with phasors and impedance (for this exam, be able to find Thevenin equivalent for simple circuits, such as Problem 8.26; we'll do more complicated circuits later)
• AC power: average power, RMS voltage and current, complex power, reactive power, apparent power, power factor, instantaneous power, power factor correction (by adding a capacitor in parallel with a load), and maximum power transfer to a load impedance.
• Frequency response (complex, magnitude, and phase), Bode plots, deciBel (dB) and relation to the amplitude gain (M), cutoff frequency.
• You should be able to write down a frequency response function for a circuit using a voltage divider with impedances. You should also be able to identify whether a given circuit is a LP, BP, or HP filter by considering how the impedances change with frequency.
• I probably won't ask you to sketch a Bode plot, but you should be able to interpret Bode plots that are provided (similar to our study of the crossover networks, where we considered the phasor of the signal out of each filter). This is similar to what you did in Labs 1 and 2, where you created Bode plots by observing the sinusoidal time signals at the input and output of a filter (on the oscilloscope). You can also reverse the process, so given a Bode plot, determine what the sinusoidal time signals would look like at the input and output of the filter at a given frequency.