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Retention Assessment. Put your books away and take out a sheet of paper. Answer the questions below to the best of your ability. When you have finished, fold your paper in half and raise your hand to have your paper collected. Your score will count toward In-Class activities. 1. Quiz.
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Retention Assessment • Put your books away and take out a sheet of paper. Answer the questions below to the best of your ability. • When you have finished, fold your paper in half and raise your hand to have your paper collected. • Your score will count toward In-Class activities EGR 101 1
Quiz • 1. What is the relationship between current and charge? • 2. Express voltage in terms of charge, energy, and/or time. • 3. Express Power in terms of charge, energy, and/or time. • 4. State Ohm’s Law. EGR 101 2
Today’s AgendaChapter 4 Series Circuits Voltage Divider 3
Series Circuit • Series Circuit – a circuit that contains only one current path EGR 101 4
Series Circuit Characteristics • Current Characteristics – the current through any element in a series circuit must equal the current through every other element in the circuit EGR 101 5
A B C E D F Series Connections • Two elements are connected in series if ALL of the current of one element flows through the second. • Which of the following are in series? EGR 101 6
Relation to Lab Activity • In the lab last week, for one of the circuits, you had 2 resistors connected as shown to the right (with different values) and a meter set on Ohms measuring them. Are the resistors in series? • What resistance would the multimeter read if you built this circuit? • What would the meter read if you put 10 22k-Ohm resistors in series? EGR 101 7
Series Connection Characteristics • Total Series Resistance where RT = the total series resistance Rn = the highest-numbered resistor in series EGR 101 8
Example Series Circuit V1 V2 • What is the total resistance? • What is the current, IT? • What is the voltage across each resistor? EGR 101 9
Kirchhoff’s Voltage Law • Note, in the example on the previous page,Vs= V1 +V2 EGR 101 10
Series Circuit Characteristics • Series circuits have the following voltage characteristic: where VS = the source (or total supply) voltage Vn = the voltage across the highest numbered resistor in the circuit EGR 101 11
Voltage Relationships • Kirchhoff’s Voltage Law • The sum of the component voltages in a series circuit must equal the net source voltage • 1840 – German Physicist, Gustav Kirchhoff EGR 101 12
Series Circuit Characteristics • Power Characteristics where PS = the source power PT = the total power dissipated by the circuit Pn = the power that is dissipated across the highest numbered resistor in the circuit EGR 101 13
Team Activity # 1: Refer to Figure 4.45(d) on p. 125 of textbook Method 1: • Calculate the total resistance of the circuit, RT. • Calculate I using RT and Ohm’s Law. • Calculate the total power PT using Vs and I. Method 2: • Calculate I using Ohm’s Law. • Calculate the voltage across each resistance, V1, V2,V3 & V4. • Calculate the power in each resistor P1, P2, P3 & P4. EGR 101 14
Comparison of Results • Questions: • Does the VTyou computed in Method 2 equal Vs from Method 1? • Does the sum of P1, P2, P3 & P4 equal PT from Method 1? EGR 101 15
Voltage Notations • Single subscript, VA– indicates the voltage is measured from the specified point relative to ground • Two subscripts, VAB– indicates the voltage is measured from the first identified point to the second A } + VA _ A } + VAB _ } + B V? _ EGR 101 16
Voltage Divider • The Voltage Divider Relationship– Often used to analyze a portion of a series circuit • Allows us to determine individual voltages RestofCircuit } A V1 } V2 } V3 B EGR 101 17
Voltage Divider Relation • For a series combination of N resistors with Vs (VAB in previous slide) applied across them, the voltage across Rn is: where Rn = the resistor n of interest Vn = the voltage across across Rn RT = the total series resistance EGR 101 18
Team Activity # 2: Refer to Figure 4.46(c) on p. 125 of textbook • Calculate the voltage across each resistor, R1, R2, & R3 by the Voltage Divider Method. • What is the resistance from point A to ground? • Calculate the current through each resistor using your results from step 1. • Calculate the current in the circuit based on Vs and total resistance. • Do your results from steps 3 and 4 agree? EGR 101 19
The Potentiometer as a Voltage Divider • Audio Amplifier Application EGR 101 20
Team Activity # 3: Refer to Figure 4.39(b) on p. 122 of textbook • Solve problem 12. EGR 101 21