1. SE3910 Week 1, Class 3 Today – Introductions Safety Review Policy The course Tomorrow Lab 1, S365 (Purchase Beaglebone black kit BEFORE) Thursday Class 1-2, here (S210) SE-2811 Slide design: Dr. Mark L. Hornick Content: Dr. Hornick Errors: Dr. Yoder 1

2. Warning… Originally from: http://www.thegooglestory.com/glat.html http://www.thegooglestory.com/glat.html http://xkcd.com/356/ SE-2811 Dr.Yoder 2

3. Cartoon One source: http://www.sengpielaudio.com/calculator- ohmslaw.htm SE-2811 Dr.Yoder 3

4. Equipment (Reminder) Purchase beaglebone black kit (~$65) from Tech Support Used tomorrow (Lab1) Purchase 4GB or greater micro SD card Used Lab 3 (Optional) Tools – e.g. needle-noise pliers Check out short-term Kit (breakout board, breadboard cape, LCD cape, USB Oscilloscope) Small parts (also may desire to purchase) SE-2811 Dr.Yoder 4

5. Review: Voltage & Current What is the voltage across the resistor? SE-2811 Dr.Yoder 5 Power Supply Resistor + + - - 5V

6. Review: Resistance & Power Exercise: According to this answer,answer 20mA is (possibly) enough to fillibrate your heart. Supposing your internal resistance is 100 Ω, what voltage is needed? Image sources: http://www.electronics- tutorials.ws/resistor/res_7.htmlhttp://www.electronics- tutorials.ws/resistor/res_7.html http://paperclip.rcs.ac.uk/index.php/Basic_Elect rical_Theory SE-2811 Dr.Yoder 6

7. Equivalent Resistance Resistors that are wired in parallel or series behave exactly like their equivalent resistor If we know voltage, can find current If we know current, can find voltage. It can be tricky to recognize parallel and series circuits But there is a trick to do it! Find matching voltages – if two resistors MUST match in voltage, they are in parallel Find matching currents – If two resistors MUST matching currents, they are in series 7

8. Example1 Find matching Voltages Currents In this circuit SE-2811 Dr.Yoder 8

9. Example 2 Find matching Voltages Currents In this circuit SE-2811 Dr.Yoder 9

10. Example 3 Compute all currents & voltages SE-2811 Dr. Yoder 10

11. Example 4 If 30mA desired through V L (charging), what should R be? SE-2811 Dr.Yoder 11

12. [See other slide set for interrupts] SE-2811 Dr.Yoder 12