4.3.b form 4 combined circuits
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Transcript of 4.3.b form 4 combined circuits
Unit 8 Combination Circuits
Objectives:
• Define a combination circuit.
• List the rules for parallel circuits.
• List the rules for series circuits.
• Solve for combination circuit values.
Unit 8 Combination Circuits
Characteristics
• There are multiple current paths.
• Resistors may be in series or parallel with other resistors.
• A junction is where three or more paths come together.
• The total power is the sum of the resistors’ power.
Unit 8 Combination Circuits
Series Circuit Rules
1. The current is the same at any point in the circuit.
2. The total resistance is the sum of the individual resistances.
3. The sum of the voltage drops or the individual resistors must equal the applied (source) voltage.
Unit 8 Combination Circuits
Parallel Circuit Rules
1. The voltage across any circuit branch is the same as the applied (source) voltage.
2. The total current is the sum of the current through all of the circuit branches.
3. The total resistance is equal to the reciprocal of the sum of the reciprocals of the branch resistances.
Unit 8 Combination Circuits
Simplifying the Circuit
• Resistors in series can be combined to
form an equivalent resistance.
• Resistors in parallel can be combined to
form an equivalent resistance.
• The equivalent resistances are used to
draw simplified equivalent circuits.
Unit 8 Combination Circuits
Solving Combination Circuits
E = ? V
I = 1 A
R = ? Ω
E1 = ? V
I1 = ? A
R1 = 325 Ω
E2 = ? V
I2 = ? A
R2 = 275 Ω
E3 = ? V
I3 = ? A
R3 = 150 Ω
E4 = ? V
I4 = ? A
R4 = 250 Ω
Unit 8 Combination Circuits
Reducing Combination Circuits
Combine R1 & R2, and R3 & R4.
R = ? Ω
R1 = 325 Ω
R2 = 275 Ω
R3 = 150 Ω
R4 = 250 Ω
Unit 8 Combination Circuits
Reducing Combination Circuits
Redraw simplified circuit.
R1 + R2 = R1&2 = 600 ohms
R3 + R4 = R3&4 = 400 ohms
R = ? Ω R1&2 = 600 Ω R3&4 = 400 Ω
Calculate total resistance
Unit 8 Combination Circuits
Solving Combination Circuits
Solve for the applied voltage using Ohm’s law.
Note that the I (total) was given data.
E (source) = I (total) x R (total) = 1 x 240 = 240 V
E = 240 V
I = 1 A
R = 240 Ω
R1&2 = 600 Ω R3&4 = 400 Ω
Unit 8 Combination Circuits
Solving Combination Circuits
Solve for the branch currents using Ohm’s law.
E (source) = E1&2 = E3&4
I1&2 = E1&2 / R1&2 = 240/600 = 0.4 A
E = 240 V
I = 1 A
R = 240 Ω
E = 240 V
I = 0.4 A
R1&2 = 600 Ω
R3&4 = 400 Ω
Unit 8 Combination Circuits
Solving Combination Circuits
Solve for the branch currents using Ohm’s law.
E (source) = E1&2 = E3&4
I3&4 = E3&4 / R3&4 = 240/400 = 0.6 A
E = 240 V
I = 1 A
R = 240 Ω
E1&2 = 240 V
I = 0.4 A
R1&2 = 600 Ω
E3&4 = 240 V
I = 0.6 A
R3&4 = 400 Ω
Unit 8 Combination Circuits
Solving Combination Circuits
Expand the circuit back to the original circuit.
Branch currents remain the same.
E = 240 V
I = 1 A
R = 240 Ω
E1 = ? V
I1 = 0.4 A
R1 = 240 Ω
E2 = ? V
I2 = 0.4 A
R2 = 240 Ω
E3 = ? V
I3 = 0.6 A
R3 = 240 Ω
E4 = ? V
I4 = 0.6 A
R4 = 240 Ω
Unit 8 Combination Circuits
Solving Combination Circuits
Solve for each voltage drop using Ohm’s law.
E1 = I1 x R1 = 0.4 x 325 = 130 V
E = 240 V
I = 1 A
R = 240 Ω
E1 = 130 V
I1 = 0.4 A
R1 = 325 Ω
E2 = ? V
I2 = 0.4 A
R2 = 275 Ω
E3 = ? V
I3 = 0.6 A
R3 = 150 Ω
E4 = ? V
I4 = 0.6 A
R4 = 250 Ω
Unit 8 Combination Circuits
Solving Combination Circuits
Solve for each voltage drop using Ohm’s law.
E2 = I2 x R2 = 0.4 x 275 = 110 V
E = 240 V
I = 1 A
R = 240 Ω
E1 = 130 V
I1 = 0.4 A
R1 = 325 Ω
E2 = 110 V
I2 = 0.4 A
R2 = 275 Ω
E3 = ? V
I3 = 0.6 A
R3 = 150 Ω
E4 = ? V
I4 = 0.6 A
R4 = 250 Ω
Unit 8 Combination Circuits
Solving Combination Circuits
Solve for each voltage drop using Ohm’s law.
E3 = I3 x R3 = 0.6 x 150 = 90 V
E = 240 V
I = 1 A
R = 240 Ω
E1 = 130 V
I1 = 0.4 A
R1 = 325 Ω
E2 = 110 V
I2 = 0.4 A
R2 = 275 Ω
E3 = 90 V
I3 = 0.6 A
R3 = 150 Ω
E4 = ? V
I4 = 0.6 A
R4 = 250 Ω
Unit 8 Combination Circuits
Solving Combination Circuits
Solve for each voltage drop using Ohm’s law.
E4 = I4 x R4 = 0.6 x 250 = 150 V
E = 240 V
I = 1 A
R = 240 Ω
E1 = 130 V
I1 = 0.4 A
R1 = 325 Ω
E2 = 110 V
I2 = 0.4 A
R2 = 275 Ω
E3 = 90 V
I 3= 0.6 A
R3 = 150 Ω
E4= 150 V
I4 = 0.6 A
R4 = 250 Ω
Unit 8 Combination Circuits
Review:
1. The three rules for series circuits are:
a. The current is the same at any point in the circuit.
b. The total resistance is the sum of the individual resistances.
c. The applied voltage is equal to the sum of the voltage drops across the individual components.
Unit 8 Combination Circuits
Review:
2. The three rules for parallel circuits are:
a. The total voltage is the same as the voltage across any branch.
b. The total current is the sum of the individual currents.
c. The total resistance is the reciprocal of the sum of the reciprocals of the branch resistances.
Unit 8 Combination Circuits
Review:
3. Combination circuits are circuits that
contain both series and parallel branches.
4. A node is where three or more paths come
together.
5. The total power is the sum of all the circuit
resistors’ power.