McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Electricity Principles & Applications Eighth Edition Chapter 3 Basic Circuits, Laws, and Measurements (student version) Richard J. Fowler McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. INTRODUCTION Circuit Symbols (p 46) Circuit Diagrams (p 45) Parts of a Circuit (p 45) Measuring Electrical Quantities (p 53) Calculating Electrical Quantities (p 47) 3 - 2

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Dear Student: This presentation is arranged in segments. Each segment is preceded by a Concept Preview slide and is followed by a Concept Review slide. When you reach a Concept Review slide, you can return to the beginning of that segment by clicking on the Repeat Segment button. This will allow you to view that segment again, if you want to

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Preview Electrical components can be represented by schematic symbols. A complete circuit needs a power source, a load, conductors, and insulation. A schematic diagram doesn’t show the physical layout of the components. Insulation, although required, isn’t shown on a schematic diagram

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. + Terminal Device Symbol Symbols and Components Symbol Device Cell (p 46) Resistor (p 43+) 3 - 5

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. This complete circuit uses the following: An energy or power source A control device A load Conductors Insulation (not shown) (p 45) 3 - 6

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Cell mA2 V  DC AC k 20K V-  COM mA V Select and arrange the components. Connect a wire from: 1) the cell to the switch, 2) the switch to the light,and 3) the light to the cell. Connect the meter,and flip the switch. Constructing and Checking a Lamp Circuit (p 58) 3 - 7

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Circuit Quiz An electrical component has a ____ as well as a name. The long bar on the cell symbol is the ____ terminal of the cell. A complete circuit has a ____ ____ that forces current to flow. A complete circuit often has a ____ ____ that turns the circuit off and on. A complete circuit has a ____ that controls the current flow. A complete circuit has ____ that route the current. symbol positive power source control device load conductors 3 - 8

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Review Electrical components can be represented by schematic symbols. A complete circuit needs a power source, a load, conductors, and insulation. A schematic diagram doesn’t show the physical layout of the components. Insulation, although required, isn’t shown on a schematic diagram. Repeat Segment 3 - 9

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Preview Select the correct function on a meter before making a measurement. Interrupt the circuit to measure current. Remove power from the circuit before measuring resistance. Observe polarity when measuring current or voltage

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c MEASURING VOLTAGE Select the dcV function Connect - lead to - terminal of source Connect + lead to + terminal of source R 1 1 k  S 1 SPST B 1 15 V (p 58)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Select the dc mA function R 1 1 k  S 1 SPST B 1 15 V MEASURING CURRENT (p 59)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. R 1 1 k  S 1 SPST B 1 15 V kk mAmVVA + V A  COM - d c a c Select the dc mA function Physically interrupt the circuit Connect the - lead so that electrons enter it Connect the + lead to the other point MEASURING CURRENT (p 59)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. MEASURING RESISTANCE  k  mAmVVA + V A  COM - d c a c Select the k  function R 1 1 k  S 1 SPST B 1 15 V (p 57)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved.  k  mAmVVA + V A  COM - d c a c Select the k  function R 1 1 k  S 1 SPST B 1 15 V Remove power (open switch) Connect the leads MEASURING RESISTANCE (p 57)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Measurement Quiz Select the correct ____ of the meter before measuring an electrical quantity. When measuring voltage, the meter’s positive lead is connected to the ____ terminal of the source. When measuring current, the meter’s ____ lead receives electrons from the circuit. When measuring ____, the meter is connected to the points created by interrupting the circuit. Power is removed from the circuit before measuring ____. function positive negative current resistance

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Review Select the correct function on a meter before making a measurement. Interrupt the circuit to measure current. Remove power from the circuit before measuring resistance. Observe polarity when measuring current or voltage. Repeat Segment

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Preview Ohm’s law states that I = V/R. Rearrangement can yield V = IR. Rearrangement also yields R = V/I. Any of three formulae can be used to calculate power

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. CALCULATING CURRENT I =I = VRVR = 36 V 1800  = 0.02 A = 20 mA S 1 SPST R 1.8 k  B 1 36 V (p 48)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. CALCULATING RESISTANCE R =R = V I V I = 24 V 0.03 A = 800  = 0.8 k  R B 1 24 V A 0.03 A (p 49)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. CALCULATING VOLTAGE V =V = IR = 0.15 A x 270   = 40.5 V R  B1B1 A 0.15 A (p 49)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. CALCULATING POWER P =  0.2 A IV =IV = 0.2 A x 54 V  = 10.8 W V 54 V P = I 2 R = 0.2 A x 0.2 A x 270  =10.8 W P = V 2 /R = (54 V x 54 V) / 270  = 10.8 W A (p 49)

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Calculation Quiz Determine I when R = 10  and V = 25 V. Determine R when I = 1.3 A and V = 26 V. Determine V when R = 15  and I = 1.2 A. Determine P when I = 3.3 A and V = 16 V. Determine P when I = 4 A and R = 20 . Determine P when V = 8 V and R = 16 . 2.5 A 20  18 V 52.8 W 320 W 4 W

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Review Ohm’s law states that I = V/R. Rearrangement can yield V = IR. Rearrangement also yields R = V/I. Any of three formulae can be used to calculate power. Repeat Segment

McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. REVIEW Circuit Symbols Circuit Diagrams Parts of a Circuit Measuring Electrical Quantities Calculating Electrical Quantities