ELECTRICAL CIRCUIT ANALYSIS
• This lesson will introduce you to electrical circuits that combine series circuits and parallel circuits.
• You will also learn how to analysis this circuits to solve for unknown quantities
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By the end of this lesson, you will be able to:
What are we going to cover today?
Draw circuit analysis cards
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Apply Kirchhoff’s laws to comb circuitsAnalysis combination circuits
Homework
KVL & KCL Review https://www.youtube.com/watch?v=Z2QDXjG2ynU
CIRCUIT ANALYSIS CARDSS
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• whenever you analyse a circuit, you must convey the information and results in a circuit analysis card. CIRCUIT ANALYSIS CARD
Circuit Item V (V) I (A) R(W)
Resistor (R1)Resistor (R2)Resistor (R3)
Resistor (RN)
Totals ..
CIRCUIT ANALYSIS STEPSS
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STEP 1a: Fill in any known quantities in your circuit analysis card
STEP 1b: Fill in any “buried” known quantities. These quantities are the ones you can assume at a glance from KLSTEP 2: Reduce any parallel element to a series equiv.STEP 3: Draw the circuit as a series equivalent circuit and calculate the total resistance by adding up the resistors.
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STEP 4: Use V = IR to find any missing variable if you are given any two out of three variables in a row of the card
STEP 5: According to KCL, all series resistors have the same current. Fill in these currents in the card.
STEP 6: Repeat STEP 4.
STEP 7: Use KVL to determine any unknown voltages.
STEP 8: Repeat STEP 4.
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sEx 1:Analyse the following circuit
Vo = 120. V
R1 = 5.00 W
R4 = 20.0 W
R2 = 10.0 W R3 = 15.0 W
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Step 1a:
CIRCUIT ANALYSIS CARD
Circuit Item V (V) I (A) R(W)
Resistor (R1) 5.00
Resistor (R2) 10.0
Resistor (R3) 15.0
Resistor (R4) 20.0
Totals 120
Step 1b: can’t be done
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2 3 2 3
1 1 1R R R
1 110 15
W2 3R 6.0
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Vo = 120. V
R1 = 5.00 W
R4 = 20.0 W
R2-3 = 6.0 W
RT = R1 + R2-3 + R4 = 31.0 W
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CIRCUIT ANALYSIS CARD
Circuit Item V (V) I (A) R(W)
Resistor (R1) 5.00
Resistor (R2) 10.0
Resistor (R3) 15.0
Resistor (R4) 20.0
Totals 120 31
Step 4: Use Ohm’s Law to find Io
oo
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120I 3.87 A
31
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According to KCL: I1 = I2-3 = I4 = IT = 3.87 A
CIRCUIT ANALYSIS CARD
Circuit Item V (V) I (A) R(W)
Resistor (R1) 3.87 5.00
Resistor (R2) 10.0
Resistor (R3) 15.0
Resistor (R4) 3.87 20.0
Totals 120 3.87 31.0
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1 1 1
4 4 4
V R I 19.4 VV R I 77.4 V
CIRCUIT ANALYSIS CARD
Circuit Item V (V) I (A) R(W)
Resistor (R1) 19.4 3.87 5.00
Resistor (R2) 10.0
Resistor (R3) 15.0
Resistor (R4) 77.4 3.87 20.0
Totals 120 3.87 31.0
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V3
2
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V 120 19.4 77.423.2 V
V 120 19.4 77.423.2 V
CIRCUIT ANALYSIS CARD
Circuit Item V (V) I (A) R(W)
Resistor (R1) 19.4 3.87 5.00
Resistor (R2) 23.2 10.0
Resistor (R3) 23.2 15.0
Resistor (R4) 77.4 3.87 20.0
Totals 120 3.87 31.0
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2
3
23.2I 2.32 A
10.023.2
I 1.55 A15
CIRCUIT ANALYSIS CARD
Circuit Item V (V) I (A) R(W)
Resistor (R1) 19.4 3.87 5.00
Resistor (R2) 23.2 2.32 10.0
Resistor (R3) 23.2 1.55 15.0
Resistor (R4) 77.4 3.87 20.0
Totals 120 3.87 31.0
PRACTICE QUESTIONS
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SMART Response Question
1. A
HOMEWORKS
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