Download SCHEDA DI PROGRAMMAZIONE DISCIPLINARE

CLIL MODULE:
Resistive Electrical Networks
Prof. Giovanni Persia
I.T.I.S. Vibo Valentia
1. Target class: third class of high school (I.T.I.S)
2. Time: 10 hours to be used to:
 selection of content
 communication
Topic
Resistive Electrical networks
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CONTENTS
Atom’s electrical
characteristics
Insulating materials,
conductors and
semiconductors.
Ohm’s law.
Electric generators
 Voltage source
 Current source
Parallel and series
resistors
Kirchoff laws.
 Kirchoff Voltage
law
 Kirchoff Current
law
Voltage and current
dividers.
Effects superposition
principle
Energy and power.
3.
Time (hr)
10
selection of content
5
communication
5
COGNITION (Cognitive skills) COMMUNICATION (Language)
 How to represent simple circuits  Develop new vocabulary related
to electrical circuits
with resistors and generators.
 Use newly acquired vocabulary
 How to calculate and measure
in context
the voltage drop across a resistor.  Study multiple meaning words
 How to represent currents and
 Recognize word origin
voltages on an electrical circuit.
 How to calculate
 equivalent series resistance
 equivalent parallel resistance
 How to apply Kirchhoff laws.
 How to apply Voltage and
current dividers rules.
 How to apply effects
superposition principle
 Distinguish between energy and
power.
SKILLS
Learning outcomes
 Knowing how to perform simple electrical circuits.
 Handle the use of technological tools paying attention to security in the working and living
places, the protection of the person, the environment and land.
 Use hardware and software tools in the study, research and discipline deepening.
 Be aware of the technologies potential and limitations in the cultural and social context in
which they are applied.
4. Methodologies
 Frontal lessons
 Flipped classroom
 Peer to peer
 laboratory lesson
 Working group
 Individualized processes
 cooperative learning
5. TOOLS
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laboratory equipment (breadboard, resistors, sources, probes, multimeters, etc..)
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multimedia tools
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virtual tools (Electric CAD Multisim)
 textbook
 material provided by the teacher
(1) BRAINSTORMING ACTIVITY: WHAT DO
YOU KNOW ABOUT ELECTRICAL
CIRCUITS?
Look at the following pictures: try to identify the electrical
components and tools.
(2) READ THE FOLLOWING PASSAGE AND...
An electric circuit is a path in which electrons from a voltage or current source flow. The point
where those electrons enter an electrical circuit is called the "source" of electrons. The point where
the electrons leave an electrical circuit is called the "return" or "earth ground". The exit point is
called the "return" because electrons always end up at the source when they complete the path of an
electrical circuit.
The part of an electrical circuit that is between the electrons' starting point and the point where they
return to the source is called an electrical circuit's "load" (such as resistors). The load of an
electrical circuit may be as simple as those that power electrical appliances like refrigerators,
televisions, or lamps or more complicated, such as the load on the output of a hydroelectric power
generating station.
Circuits use two forms of electrical power: alternating current (AC) and direct current (DC). AC
often powers large appliances and motors and is generated by power stations. DC
powers battery operated vehicles and other machines and electronics. Converters can change AC to
DC and vice versa. High-voltage direct current transmission uses very big converters.
Electronic circuits usually use low voltage direct current sources. The load of an electronic circuit
may be as simple as a few resistors, capacitors, and a lamp, all connected together to create the flash
in a camera. Or an electronic circuit can be complicated, connecting thousands of resistors,
capacitors, and transistors. It may be an integrated circuit such as the microprocessor in a computer.
Resistors and other circuit elements can be connected in series or in parallel. Resistance in series
circuits is the sum of the resistances.
A circuit diagram or wiring diagram uses symbols to represent parts of a circuit. Electrical and
electronic circuits can be complicated. Making a drawing of the connections to all the component
parts in the circuit's load makes it easier to understand how circuit components are connected.
Drawings for electronic circuits are called "circuit diagrams". Drawings for electrical circuits are
called "wiring diagrams". Like other diagrams, these diagrams are usually drawn by
skilled draftsmen, and then printed. Diagrams may also be created digitally using specialized
software.
A schematic is a diagram of an electrical circuit. A schematic only gives an idea of what a circuit is,
and so it shows the essential connections. Schematics use symbols to represent components in the
circuit. We use conventions in a schematic, we use them to represent the way electricity flows. The
common convention we use is from the positive to the negative terminal. The realistic way
electricity is from the negative to the positive terminal.
.... (3) BUILD YOUR OWN GLOSSARY
Complete the following table, writing the translation of the terms. You can
personalize the table by adding other terms that you don’t know yet and finding out
the correct translation using a dictionary.
English
Italian
electric circuit
electrons
current
source
earth ground
load
resistors
lamps
hydroelectric power
generating station
alternating current
Sorgente,
generatore
English
Italian
direct current
DC
powers battery
Converters
High-voltage
Corrente continua
capacitors
integrated circuit
microprocessor
wiring diagram
draftsmen
disegnatore
(4) Metals, Insulators, Semiconductors
An electric current is a flow of electric charge. In electric circuits this charge is often carried by
moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and
electrons such as in a plasma.
The SI unit for measuring an electric current is the ampere [A]: which is the flow of electric charge
across a surface at the rate of one coulomb per second.
Electric current is measured using a device called an ammeter.
Electric currents cause Joule heating (Joule effect), which creates light in incandescent light bulbs.
They also create magnetic fields, which are used in motors, inductors and generators.
A Voltage may represent either a source of energy (electromotive force), or lost, used, or stored
energy (potential drop). The voltage between point A to point B is equal to the work which would
have to be done, per unit charge, against or by the electric field to move the charge from A to B.
The particles that carry the charge in an electric current are called charge carriers.
In metals, one or more electrons from each atom are loosely bound to the atom, and can move
freely about within the metal. These conduction electrons are the charge carriers in metal
conductors.
In insulators instead the electrons are strongly bound to the nucleus and cannot move. There is no
electric current.
Semiconductors are defined by their unique electric conductive behavior, somewhere between that
of a metal and an insulator. The semiconductor materials are used in all electronic devices.
Reading Comprehension exercises
Lots
1. What is an electric current?
2. What is the SI unit for measuring an electric current?
3. An electric current is measured by…
4. What is a Voltage?
5. What is the Joule effect?
Hots
1. Explain the differences between metals, insulators, semiconductors.
2. In which way are the electrons bound to the nucleus of the atom in an insulator?
3. In which way are the electrons bound to the nucleus of the atom in a metal?
4. When can we observe the Joule effect in action
(5) OHM’S LAW EXERCISES
Fill in the blanks with the following words:
 Resistance (2 times)
 conductor
 potential difference
 current (2 times)
 Volts
 Proportional
 Ohms
Ohm's law states that the …….. through a …….. between two points is directly …….. to the
potential difference across the two points. Introducing the constant of proportionality, the
…………, one arrives at the usual mathematical equations that describes those relationships:
where I is the …………. through the conductor in units of amperes [A], V is the …………
measured across the conductor in ………….. [V], and R is the ………………. of the conductor
in ……………… [].
EXERCISES
1. If V = 5V, I = 2A
b. R = 2V
c. R = 2
d. R = 2,5AV
e. R = 2,5
2. If V = 5V, R = 2
a. I = 2V
b. I = 2
c. I = 2,5A
d. I = 25A
3. If I = 5A, R = 2
a. V = 10V
b. V = 2
c. V = 2,5V
d. V = 2,5A
(6) KIRCHHOFF'S LAW
Kirchhoff's laws are two equalities that correlate the potential differences at the terminals of the
devices within a mesh or the currents that flow in a node in the electric circuits. They were
described in 1845 by the German physicist Gustav Kirchhoff. Widely used in electrical engineering,
they are also called Kirchhoff's rules or simply Kirchhoff's laws.
Kirchhoff's current law (KCL)
At any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to
the sum of currents flowing out of that node
for the example in figure:
i2 + i3 = i1 + i4
Kirchhoff's voltage law (KVL)
The sum of all the voltages in a mesh is equal to zero
Representation of currents and voltages in an electrical circuit: arrows (current arrows or
voltage arrows) are used. For users: current arrows and voltage arrows have opposite verse; for
generators: current arrows and voltage arrows have the same verse. Fixed a path direction in a
mesh, if you find the end of the arrow before, the voltage is negative, otherwise it is positive. The
current is outgoing from the generator
for the example in figure:
VAB + VBC + VCD -V= 0 → V =VAB + VBC + VCD
Exercises
For the mesh in the figure:
 Put current and voltage arrows on each device;
 Find the relationship between voltages, using the Kirchhoff's voltage law (KVL)
 Find the relationship between currents, using the Kirchhoff's current law (KCL)
 Find current and voltage values in the mesh