2. page 28/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
To control or reduce the flow of
current from a certain energy source .
2
3. page 38/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
Resistor
Fixed
Resistor
Light
Dependent
Resistor
Thermal
Resistor
Variable
Resistor
THE SYMBOLS .
THE UNIT .
Ohm
4. page 48/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
This resistor has a fixed value so you can not change the value.
Variable Resistor .
You can change the value in terms ranging between zero and the maximum value of its.
5. page 58/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
This resistor is changing by amount of light falling on it .
Thermal Resistor .
This resistor is sensitive to heat and change its
resistance with temperature change . symbol
6. page 68/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
2) Resistor Color Code
7. page 78/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
How do we know which color corresponds to which number?
Answer: Using the Resistor Color Code Table
8. page 88/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
Handout 1 : A) Determine the nominal resistance value and the tolerance for the
resistor shown below.
Solution:
Nominal value = 10102
= 1,000
Tolerance = 5%.
___ ___ 10 ____ %1
Brown =1
0
Black =0
2
Red =2
5
Gold = 5%
9. page 98/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
B) Determine the nominal resistance value and the tolerance for the
resistor shown below.
Solution:
___ ___ 10 ____ %
Resistor nominal value = 39105
= 3,900,000
= 3.9M.
Orange =3
3
White =9
9
Green =5
5
Silver = 10%
10
Tolerance = 10%
11. page 118/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
Resistors in Series and Parallel Circuits
Connected any resistors in parallel that the resistor parallel
the next resistor until both ends to connects to voltage
source, that mean the current passes in two or more as the
number of lanes in the circuit.
parallel Circuits .
Series Circuits.
12. page 128/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
Resistors in circuits
Ohm's law
Resistors in Series
When connected in series, the total resistance (Rt) is
equal to:
Rt = R1 + R2 + R3 +…
The total resistance is always larger than any individual
resistance.
Resistors in Parallel
When connected in parallel, the total resistance (Rt) is
equal to:
1/Rt = 1/R1 + 1/R2 + 1/R3 +…
Due to this reciprocal relationship, the total resistance
is always smaller than any individual resistance.
13. page 138/21/2010
Vocational Pedagogy
M2 - Didactics and Teaching practice
VP-4 / AVP-1 - Lesson planning and Teaching techniques / Teaching practice
10 V
15 Ω
10 Ω
6 Ω
a) Calculate the total current through the circuit.
Rt = 15 Ω +10 Ω + 6 Ω
Rt = 31 Ω
I = V/Rt = 10 V/ 31 Ω =0.32 A
1/Rt = 1/12 Ω +1/4 Ω + 1/6 Ω
1/Rt = 1/500m Ω
Rt = 2 Ω
12 Ω
4 Ω
6 Ω
b) Calculate the total resistor through the circuit.
