1. SE-3910 Real-time Systems Week 2, Class 2 – Return stuff, New HW Assignment! – Quiz! (Possibly with review) Ohm’s Law Kirkhoff’s Current Law Switches Using/reading an oscilloscope Frequency / Period – Signals Square, Sine, Saw-tooth, Random Pulse Width Modulation (PWM) SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling, Some from Dr. Hornick, etc. 1

2. Waveform Terminology Amplitude Peak-to-peak voltage Peak voltage (alternative defs) Period Frequency (review) SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 2

3. Sketching & Listening to Waveforms Sine wave Square wave Sawtooth wave(s) Random wave Efffect of changing – Amplitude – Frequency – Phase (time shift) On sound! SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 3

4. Technical Goals How does one control the speed of a motor? How does one change the brightness of a light-bulb? SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 4

5. Pulse-Width-Modulation … in traffic SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 5

6. Pulse-width modulation terminology SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 6 Determine the duty cycle (D) Multiply the duty cycle by the peak volta ge (V p )

7. In-class exercise How can you control the brightness of an LED, using tools we have discussed so far? How would you accomplish this if you went into lab right now? SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 7

8. Advantages of Pulse-Width Modulation Click to add text SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 8

9. Power of a signal (If time) P = IV I = V/R P = … Let R = 1 (Ohm) What is the instantaneous power of a sinusoid? What is the average power of a sinusoid? What is the average power of a PWM signal? SE-3910 - Dr. Josiah Yoder Slide style: Dr. Hornick Much Material: Dr. Schilling 9