1. Introduction to Electrical & Computer Engineering Ohm’s Law
Dr. Cynthia Furse
University of Utah
Dr. Cynthia Furse
University of Utah

2. Ohm’s Law – Questions of the Day
•What is Ohm's Law, and how do you apply it?
•What are Resistance, Conductivity,–Resistivity? 
* What is resistance used for?

3. Find Currents & Voltages

4. Find Currents & Voltages

5. Resistance (R) and Resistivity (ρ)
Resistance: ability to resist flow of electric current
Resistance (R ) Ω (ohms)
Resistivity (r) Ω/m (ohm-meters)
Conductivity (σ ) m/Ω -1
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS Press, Used with Permission by the Publisher

6. Problem 2.1: AWG-14 Cu wire R = 17.1 ohms, T = 20C. Find length.
Resistance (R ) Ω (ohms)
Resistivity (r) Ω/m (ohm-meters)
Conductivity (σ ) m/Ω
From Table 2-2:
AWG-14 d = 1.6mm
A = π r = π (1.6mm / 2) 2 2
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press

7. Circuits, Second Edition by Fawwaz T. Ulaby and Michel M
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS Press, Used with Permission by the Publisher

8. Resistor Color Codes 1 k ohm 2.4 kohm 4.3 Mohm
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Circuits, Second Edition by Fawwaz T. Ulaby and Michel M. Maharbiz, © NTS Press, Used with Permission by the Publisher

9. Water-Circuit Analogy
Voltage
(Potential)
Resistance
(Rocks/Pipes)
Current
(Flow)

10. How to Connect hoses in…
Series
Parallel

11. How is this applied to sea ice?