20.3 Complex Resistor CombinationsDate, Section, Pages, etc.

Mr. Richter

Agenda

Warm-Up Review HW

p. 744 #1-4 p. 745 #1-6

Complex Resistor Combinations Complex Circuit Problem Solving

Equivalent Resistance Current and Voltage Drops

Objectives: We Will Be Able To… Determine the equivalent resistance of a complex

resistor combination. Determine the current through and voltage drop across

a resistor within a complex resistor combination.

Warm-up

Calculate the equivalent resistance of an 8.0 Ω resistor and a 4.0 Ω resistor arranged in parallel.

Complex Resistor Combinations

Complex Resistor Combinations

Most circuits are not purely series circuits or purely parallel circuits.

Most circuits are a combination of series and parallel circuits.

Equivalent Resistance

Equivalent Resistance

To determine the equivalent resistance in a complex circuits:

1. Redraw the circuit in a line.

2. Combine all resistors in series and redraw

3. Combine all resistors in parallel and redraw

4. Repeat

Equivalent Resistance: Redraw the Circuit in a Line

=

Equivalent Resistance: Resistors in Series

3.0 Ω 6.0 Ω6.0 Ω 2.0 Ω

4.0 Ω

1.0 Ω

Equivalent Resistance: Resistors in Series

3.0 Ω 6.0 Ω6.0 Ω 2.0 Ω

4.0 Ω

1.0 Ω8.0 Ω

9.0 Ω

Equivalent Resistance: Resistors in Parallel

4.0 Ω

1.0 Ω8.0 Ω

9.0 Ω

Equivalent Resistance: Resistors in Parallel

1.0 Ω

4.0 Ω

8.0 Ω

9.0 Ω 2.7 Ω

Equivalent Resistance: Repeat (Resistors in Series)

1.0 Ω

9.0 Ω 2.7 Ω12.7 Ω

Current and Voltage Drops

Current and Voltage Drops

To find the current through and voltage drop across a specific resistor, work your way back from the equivalent resistors!

1. Calculate the current.

2. Then the voltage drops.

3. Redraw and repeat.

12.7 Ω =3.0 Ω 6.0 Ω6.0 Ω 2.0 Ω

4.0 Ω

1.0 Ω

Current and Voltage Drops

12.7 Ω

I = 0.71 A1.0 Ω

9.0 Ω 2.7 Ω

Current and Voltage Drops

I = 0.71 A1.0 Ω

9.0 Ω 2.7 ΩV = 1.9V

Current and Voltage Drops

1.0 Ω

4.0 Ω

8.0 Ω

9.0 Ω 2.7 Ω

V = 1.9V

Current and Voltage Drops

1.0 Ω

4.0 Ω

8.0 Ω

9.0 Ω

V = 1.9V I = 0.24 A

6.0 Ω 2.0 Ω

Current and Voltage Drops

1.0 Ω

4.0 Ω9.0 Ω

I = 0.24 A

6.0 Ω 2.0 Ω

V = (0.24 A)(2.0Ω)V = 0. 48 V

Wrap-Up: Did we meet our objectives?

Determine the equivalent resistance of a complex resistor combination.

Determine the current through and voltage drop across a resistor within a complex resistor combination.

Homework

Due Thursday: p. 752 #1-9