Introduction to Electrical & Computer Engineering Circuit Elements 1 Dr. Cynthia Furse University of Utah

Circuit Elements (2) Voltage & Current Sources – Dependent / Independent – Ideal / Non-Ideal – i-v curves Open, Short Circuits Switches – Wiring Three-Way switches 2

Ideal Voltage and Current Sources 3 vs is

Non-Ideal Voltage & Current Sources 4 vs - - I + Rs is - Rs

Internal Resistance 5 Energizer Tech Bulletin Battery Internal Resistance ver 1.1.0, Dec 05

How does this affect you? 6 vs - - is + Rs Rload = 1Ω

This is (one reason) WHY our batteries went dead so fast in Antarctica! 7

I-V Curves used for diagnosis, design, etc. 8 Voltage (V) Current (I) V = I R 1V 1mA R=1kΩ 0.5mAR=2kΩ V R I R=0 R= ∞

I-V Curves for LED (Vf is where light turns on) 9

Open Circuit R = ∞ I = 0 Short Circuit R = 0 I = ∞ 10

Fuse / Circuit Breaker I ≠ ∞ 11 panels

Switches 12 Single Pole Single Throw (SPST) Single Pole Double Throw (SPDT) And more…

Three-Way Light Switch Wiring 13

Conclusion Circuit Elements Voltage & Current Sources – Dependent / Independent – Ideal / Non-Ideal – i-v curves Open, Short Circuits Switches – Wiring Three-Way switches 14

Sunflowers & Thunderheads Blackhawk Trail Payson Canyon, Utah 15