MODULE-3-Basic-CircuitswithOhmsLaw-1.pdf

Basic-Circuits with Ohms Law-1.pdf

1. MODULE 3: Basic Circuits -Resistance
SUMMER CHALLENGE
Electrical Engineering: Smart Lighting
Prachi Shukla
PhD Candidate
Boston University
[email protected]

2. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Overview
Circuits Review
Resistance and Resistors
Ohms Law
Breadboards
Capacitance
Experiments
Resistive Circuit
Voltage Divider
RC Circuit
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3. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Recap -What is a Circuit?
In a circuit, how are the start and end related?
They’re the same!
What happens if there isn’t a continuous path?
Open Circuit –No flow of charge (or electrons)
What happens when a conduit connects two points?
Charge (and electrons) can flow between the points
Short Circuit –Directly connecting two points of different voltage
Switch
Device that can open or close a circuit
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4. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Resistance
As charge flows from high to low V, energy is released
Where does it go??
As electrons flow, they encounter resistance
Generate heat as a result of this opposition
Resistance is a function of material, length, and cross-sectional area
Resistance is measured in Ohms [Ω]
Wires have resistance, but it is minimal and a direct
connection between different voltage levels is a short
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Incandescent
Light
The filament in an incandescent
light introduces resistance
The heat energy causes the filament to
“glow” white-hot and produce light

5. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Resistors
5
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??
??

6. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Ohm’s Law
German professor who published a book in 1827
that includes what is now known as Ohm's law
Ohm's Law: Voltage across a resistor is directly
proportional to the current flowing through it.
The proportionality constant is the resistance!
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??????=????????????R
i
+
-
v+
-
??????
??????=
??????
??????
??????=
??????
??????
Georg Simon Ohm
(1789 –1854)
What happens in the case of an open circuit (i.e., ??????≈∞)?
What happens in the case of a short circuit (i.e., ??????≈0)?
??????=????????????

7. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Series vs Parallel
Series Resistance
Parallel Resistance
7V
0
I
R
1
R
2
V
1
V
2
A
+
+
-
- V
R
1
I
R
2
I
1 I
2 V
R
I
p V
R
I
s 0 1 2 1 2
V V V IR IR     
12
I R R s
IR 12
12
VV
I I I
RR
    12
11
V
RR


 p
V
R
 12
1 1 1
p
R R R
 12s
R R R 12
12
p
RR
R
RR



8. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Breadboards
Why do we use breadboards?
Temporary Circuits
Prototyping
No Soldering
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9. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Anatomy of a Breadboard
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10. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Schematics and Breadboards
Connect nodes of a schematic to a connected row of the breadboard
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11. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Schematics and Breadboards
Connect nodes of a schematic to a connected row of the breadboard
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12. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
LED
RESISTOR
POSITIVE NEGATIVE
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13. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
SHORT EXERCISE
1.Copy the schematic.
2.Label where each of the
numbers are.
1
2 34 5
6
7
8
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14. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Voltage Divider Circuit
14V
0
I
R
1
R
2
V
1
V
2
A 00
12s
VV
I
R R R

  
0
2 2 2
12
V
V IR R
RR

  
2
20
12
R
VV
RR

  
1
10
12
Also
R
VV
RR



15. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Experiment I
Voltage Divider
Resistive Circuits
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16. Boston UniversitySlideshow Title Goes Here
Module 3: Basic Circuits
Recap
What did you today?
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