EGR Example Series Circuit What is the total resistance? What is the current, I T ? What is the voltage across each resistor? V1V1 V2V2

EGR Kirchhoff’s Voltage Law Note, in the example on the previous page, V s = V 1 +V 2

EGR Series Circuit Characteristics Series circuits have the following voltage characteristic: where V S = the source (or total supply) voltage V n = the voltage across the highest numbered resistor in the circuit

EGR 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 Series Circuit Characteristics Power Characteristics where P S = the source power P T = the total power dissipated by the circuit P n = the power that is dissipated across the highest numbered resistor in the circuit

EGR Team Activity # 1: Refer to Figure 4.45(d) on p. 125 of textbook Method 1:  Calculate the total resistance of the circuit, R T.  Calculate I using R T and Ohm’s Law.  Calculate the total power P T using V s and I. Method 2:  Calculate I using Ohm’s Law.  Calculate the voltage across each resistance, V 1, V 2,V 3 & V 4.  Calculate the power in each resistor P 1, P 2, P 3 & P 4.

EGR Comparison of Results Questions:  Does the V T you computed in Method 2 equal V s from Method 1?  Does the sum of P 1, P 2, P 3 & P 4 equal P T from Method 1?

EGR Single subscript, V A – indicates the voltage is measured from the specified point relative to ground Two subscripts, V AB – indicates the voltage is measured from the first identified point to the second Voltage Notations A } VAVA } V AB A B } V?V? + _ + _ + _

EGR Voltage Divider The Voltage Divider Relationship – Often used to analyze a portion of a series circuit Allows us to determine individual voltages Rest of Circuit A B } } } V1V1 V2V2 V3V3

EGR Voltage Divider Relation For a series combination of N resistors with V s (V AB in previous slide) applied across them, the voltage across R n is: where R n = the resistor n of interest V n = the voltage across across R n R T = the total series resistance

EGR Team Activity # 2: Refer to Figure 4.46(c) on p. 125 of textbook 1.Calculate the voltage across each resistor, R 1, R 2, & R 3 by the Voltage Divider Method. 2.What is the resistance from point A to ground? 3.Calculate the current through each resistor using your results from step 1. 4.Calculate the current in the circuit based on V s and total resistance. 5.Do your results from steps 3 and 4 agree?

EGR Audio Amplifier Application The Potentiometer as a Voltage Divider

EGR Team Activity # 3: Refer to Figure 4.39(b) on p. 122 of textbook  Solve problem 12.