ohm’s law foundations of technology ohm’s law © 2013 international technology and engineering...
Post on 19-Jan-2016
216 Views
Preview:
TRANSCRIPT
Foundations of Technology
Ohm’s LawOhm’s Law
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
Teacher Resource – Unit 4 Lesson 4
The BIG IdeaThe BIG Idea
Big Idea:
Troubleshooting allows users to continue to use and maintain the proper operation of a system or product.
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
Proposed by George Ohm, and is the relationship between Voltage, Current and Resistance.
Voltage (V) = Current (I) X Resistance (R)
Ohm’s LawOhm’s Law
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
-
+V
R
I
V
I R
Ohm’s Law is commonly expressed using the triangle found below where:
Voltage (V) = Current (I) X Resistance (R)
Current (I) = _Voltage (V)__ Resistance (R)
Resistance (R) = _Voltage (V)_ Current (I)
Ohm’s LawOhm’s Law
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
Voltage (V) is the electrical force that moves electrons through a conductor.
Voltage is electrical pressure that pushes electrons.
VoltageVoltage
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
Current (I) is the quantity or flow rate of electrons moving past a point.
Current flow is also known as amperage, or amps for short.
CurrentCurrent
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
Resistance (R) is the force that reduces or stops the flow of electrons and opposes voltage.
ResistanceResistance
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
Using Ohm’s Law determine the missing value for the following circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
R
I
4.5
0.5 Amp
= ______Ώ
Using Ohm’s Law determine the missing value for the following circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
R
I
4.5
0.5 Amp
= ______Ώ
Resistance (R) = Voltage (V) Current (I)
R = 4.5V 0.5Amp
R = 9Ώ
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
R
I
10 Ώ
0.5 Amp
_____
I = ______ Amp
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
R
I
10 Ώ
0.5 Amp
_____
I = ______ Amp I = 0.5 Amp - Current will be the same throughout the circuit
Voltage (V) = Current (I) x Resistance (R)
V = 0.5 Amp x 10 Ώ
V = 5V
In a Series circuit, the current through two or more resistors is the same, and the circuit is connected in a series.
The total resistance of the collection is the sum of individual resistances.
Resistors in SeriesResistors in Series
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
The total resistance of the collection is the sum of the individual resistances.
The Equivalent Resistance of R1, R2 and R3 when connected in series is:
R = R1 + R2 + R3
Resistors in SeriesResistors in Series
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
Calculate the total resistance of the series circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
I
9
5 Ώ
10 Ώ
3 Ώ
Calculate the total resistance of the series circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
I
9
5 Ώ
10 Ώ
3 Ώ
R = R1 + R2 + R3
R = 3 Ώ + 10 Ώ + 5 Ώ
R = 18 Ώ
Calculate the total current of the series circuit: (current is the same throughout a series circuit)
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
I
9
5 Ώ
10 Ώ
3 Ώ
R(total) = 18 Ώ
Calculate the total current of the series circuit:(current is the same throughout a series circuit)
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
I
9
5 Ώ
10 Ώ
3 Ώ
R(total) = 18 Ώ
Current (I) = Voltage (V) Resistance (R)
I = 9V 18 Ώ
I = 0.5 Amp
Using Ohm’s Law, calculate the voltage drop for each resistor in the series circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
I
9
5 Ώ
10 Ώ
3 Ώ
0.5 Amp
Using Ohm’s Law, calculate the voltage drop for each resistor in the series circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
I
9
5 Ώ
10 Ώ
3 Ώ
V = I x R
V(R1) = 0.5 Amp x 3 ΏV(R1) = 1.5 V
V(R2) = 0.5 Amp x 10 ΏV(R2) = 5 V
V(R3) = 0.5 Amp x 5 ΏV(R3) = 2.5 V
0.5 Amp
Using Ohm’s Law, calculate the voltage drop for each resistor in the series circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
I
9
5 Ώ
10 Ώ
3 Ώ
R1 R2 R3 Total
1.5 5 2.5 9 V Voltage
0.5 0.5 0.5 0.5 Amp Current
3 10 5 18 Ώ Resistance
Remember Current (I) is the same across a
series circuit.
0.5 Amp
In a Parallel circuit, the voltage through two or more resistors is the same, and the circuit is connected in parallel.
The total resistance of the collection is divided among the three resistors .
Resistors in ParallelResistors in Parallel
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
The total resistance of the collection is divided among the three resistors.
The Equivalent Resistance of R1, R2 and R3 when connected in parallel is:
1/R = 1/R1 + 1/R2 + 1/R3
Resistors in ParallelResistors in Parallel
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
Calculate the total resistance of the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-
+V
14.4 Amp
10 Ώ 1 Ώ
2 ΏI
Calculate the total resistance of the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
1/R = 1/R1 + 1/R2 + 1/R3
1/R = 1/(10 Ώ) + 1/(2 Ώ) + 1/(1 Ώ)
1/R = 0.1 Ώ + 0.5 Ώ + 1 Ώ
1/R = 1.6 Ώ
R = 1/(1.6 Ώ)
R = 0.625 Ώ
-
+V
14.4 Amp
10 Ώ 1 Ώ
2 ΏI
Calculate the total voltage of the parallel circuit: (voltage is the same across a parallel circuit)
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
R(total) = 0.625 Ώ
-
+V
14.4 Amp
10 Ώ 1 Ώ
2 ΏI
Calculate the total voltage of the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
R(total) = 0.625 Ώ
Voltage (V) = Current (I) x Resistance (R)
V = 14.4 Amp x 0.625 Ώ
V = 9V
-
+V
14.4 Amp
10 Ώ 1 Ώ
2 Ώ
Calculate the total voltage of the parallel circuit: (voltage is the same across a parallel circuit)
I
Using Ohm’s Law, calculate the current across each resistor in the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-+
V
I
9
10 Ώ 1 Ώ
2 Ώ
14.4 Amp
Using Ohm’s Law, calculate the current across each resistor in the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-+
V
I
9
10 Ώ 1 Ώ
2 Ώ
Current (I) = Voltage (V) Resistance (R)
I(R1) = 9V 10 Ώ
I(R1) = 0.9 Amp14.4 Amp
Using Ohm’s Law, calculate the current across each resistor in the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-+
V
I
9
10 Ώ 1 Ώ
2 Ώ
Current (I) = Voltage (V) Resistance (R)
I(R2) = 9V 2 Ώ
I(R2) = 4.5 Amp14.4 Amp
Using Ohm’s Law, calculate the current across each resistor in the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
-V
Current (I) = Voltage (V) Resistance (R)
I(R3) = 9V 1 Ώ
I(R3) = 9 Amp2 Ώ
+
I
9
10 Ώ 1 Ώ
14.4 Amp
Using Ohm’s Law, calculate the current across each resistor in the parallel circuit:
Practice QuestionsPractice Questions
© 2013 International Technology and Engineering Educators Association, STEMCenter for Teaching and Learning™ Foundations of Technology
V
I R
R1 R2 R3 Total
9 9 9 9 V Voltage
0.9 4.5 9 14.4 Amp Current
10 2 1 0.625 Ώ Resistance
Remember Voltage (V) is the same across a
parallel circuit.2 Ώ
+
I
9
10 Ώ 1 Ώ
14.4 Amp
V
top related