11.9 CIRCUIT ANALYSIS
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Transcript 11.9 CIRCUIT ANALYSIS
531-535
Mixed Circuits
Contain both series and parallel
connections.
Recall from 11.6: To analyze a mixed
circuit, you can divide the circuits into
sections that are connected in parallel
and sections connected in series.
Let’s find equivalent resistance in a
mixed circuit…
Tips to Simplify a Mixed Circuit
1 - Reduce the circuit to a simple series circuit
by using equivalent resistors.
2 - Determine the total resistance and total
current of the series circuit using the equation
for RT for series circuits and Ohm’s law.
3 - Determine the voltage drop across each
resistor in the circuit using Ohm’s law.
4 - Redraw the original circuit with the voltage
drops beside each resistor.
Remember that the voltage drop across the
parallel resistors will be the same.
5 - Determine the current through the parallel
resistors using Ohm’s law.
Sample problem
Determine
the total resistance,
total current, voltage and current
through each resistor.
Sample problem
Analyze
the following circuit diagram to
solve for the current and potential
difference through each resistor.
Find Rtotal
Rseries= 600ohms
Rparallel= (1/900 + 1/1800 + 1/1200)-1
(4+2+3/3600)-1
(9/3600)-1
Rparallel= 400ohms
Rtotal=1000ohms
Find total current
I=V/R
200/1000
Itotal= 0.2A
Circuit Analysis for a Mixed Circuit
Section 11.9
This circuit has Vsource = 6.0 V, R1 = 1.5 Ω, V2 = 1.5 V, and I3 = 0.5 A.
Determine Isource, I1, V1, I2, R2, V3, R3, and Rtotal. Complete the following
calculation.
Step 1. Apply KVL to any complete pathway.
Vsource = V_ + V2
= V_ +
_____ V = V_
Step 2. Use the fact that parallel potential differences are equal.
V3 = V_ =
Step 3
Circuit Analysis for a Mixed Circuit
Section 11.9
This circuit has Vsource = 6.0 V, R1 = 1.5 Ω, V2 = 1.5 V, and I3 = 0.5 A.
Determine Isource, I1, V1, I2, R2, V3, R3, and Rtotal. Complete the following
calculation.
Step 1. Apply KVL to any complete pathway.
Vsource = V_ 1+ V2
6.0 V
= V_1 +
1.5 V
4.5 V = V_ 1
_____
Step 2. Use the fact that parallel potential differences are equal.
V3 = V_2=
1.5 V
Step 3
Circuit Analysis for a Mixed Circuit
Section 11.9
Step 3. Use Ohm’s law to find one of the unknown
current values.
V_
I_ =
R_
I_ =
_____ V
I_ = _____ A
Step 4. Apply KCL to find the missing current values.
I_ = I_ + I_
Isource = I_ =
= I_ +
_____ A = I_
Step 5
Circuit Analysis for a Mixed Circuit
Section 11.9
Step 3. Use Ohm’s law to find one of the unknown
current values.
V_1
I_1 =
R_1
4.5 V
_____
I_1 =
1.5 Ω
3.0 A
I_1 = _____
Step 4. Apply KCL to find the missing current values.
I1_ = I_2+ I_3
3.0 A
= I_2 +
2.5 A = I_ 2
_____
Isource = I_1=
3.0 A
0.5 A
Step 5
Circuit Analysis for a Mixed Circuit
Section 11.9
Step 3. Use Ohm’s law to find the unknown resistances.
R_ =
R_ =
V_
I_
_____ A
R_ = _____ Ω
R_ =
R_ =
V_
I_
_____ V
R_ = _____ Ω
Rtotal =
Rtotal =
Vsource
Isource
_____ A
Rtotal = _____ Ω
Circuit Analysis for a Mixed Circuit
Section 11.9
Step 3. Use Ohm’s law to find the unknown resistances.
R_2 =
V_2
I_2
1.5 V
R_2 =
2.5 A
_____
0.6 Ω
R_2 = _____
R_3 =
R_3 =
V_3
I_3
1.5 V
_____
0.5 A
3.0 Ω
R_3 = _____
Rtotal =
Rtotal =
Vsource
Isource
6.0 V
3.0 A
_____
2.0 Ω
Rtotal = _____
HOMEWORK
P. 532 #1
P. 534 #1
P. 535 #1-4
CH. 11 REVIEW QUESTIONS
Self quiz P. 539 #1-15
Review P. 540-545 #1-9, 12-36, 38-47, 53-56,
58, 60,62-65 70-72
Unit self quiz with Ch. 11 p. 624-625 #1-6, 1823,
Unit review with Ch. 11 p. 626-633 #1-5, 1619, 30-38, 65-68, 70-72