Download presentation

Presentation is loading. Please wait.

Published byNoelle Wheaton Modified over 2 years ago

1
Exam I coming up Feb 20 th ! (a week from TODAY) HW3 due on Friday: P.S. or Review? TEST FORMAT? 5 multi-choice 10 pts/each At least 1 (maybe 2) bonus multi-choice 5 pts/each 2 written problems (partial credit!) 25 pts/each (one may be a HW problem!) Cheat Sheet! Sample on web site: you’ll get one with the test

3
I = 2800 A (!) V = ?

4
Real vs. idealized electric circuit (next) resistor

5
Real electric circuit Resister R = 220.0000 22 AWG wire Diameter = 0.025 in R/L = 0.0161 /ft V = + 1.50000 V Define V = 0 here ! 3 ft 2 ft I

6
R = 220.0000 Idealized electric circuit (perfect wires) V = + 1.50 V Perfect wires! ( R = 0) V = 0 V I I = V R =

7
Real electric circuit R = 220.0000 V = + 1.50 V Define V = 0 here ! 3 ft 2 ft + 22 AWG wire Diameter = 0.025 in R/L = 0.0161 /ft R W2 = R W3 = Assume R T = R W2 + R + R W3 = THEN I = V / R T

8
Real electric circuit 220.0000 V = + 1.50 V Define V = 0 here ! + V W2 = I R W2 = R W2 = 0.0322 R W3 = 0.0483 V W3 = I R W3 = V R = I R =

9
But, What’s the voltage drop along a 100 ft long cable (18 AWG) when it’s carrying 20 A? (18 AWG: 0.00639 /ft)

10
100 ft Voltage drop along wires! (18 AWG: 0.00639 /ft) 110 V 20 A

11
Electric Power

12
But I is the same throughout the circuit! Electric Power

14
I constant → HEAT! power lost as heat

15
Electric Power V I Units?

16
Electric Power If R is not to burn up. It must be able to dissipate heat at a rate of V×I

17
FROM the Basics You can always derive …. + −

18
(do power in several different ways)

19
Lame resistor demo Example: Big guy is rated as 10 with max current of 6.5 Amps. What is the max power rating? Max voltage across it? Less-Lame fuse demo

20
Example: 18.30 A 115-V fish-tank heater is rated at 110 W. Calculate a) the current through the heater when it’s operating, and b) its resistance.

Similar presentations

OK

Fisica Generale - Alan Giambattista, Betty McCarty Richardson Copyright © 2008 – The McGraw-Hill Companies s.r.l. 1 Chapter 21: Alternating Currents Sinusoidal.

Fisica Generale - Alan Giambattista, Betty McCarty Richardson Copyright © 2008 – The McGraw-Hill Companies s.r.l. 1 Chapter 21: Alternating Currents Sinusoidal.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on information technology in education Ppt on store design Ppt on law against child marriages Ppt on computer software download Ppt on buildings paintings and books Ppt on email etiquettes presentation church Ppt on op amp circuits design Ppt on water scarcity Ppt on ram and rom pictures Ppt on 9/11 conspiracy proof