Chapter 1: Electricity
A cable is composed out of 3 different wires. The Black and Blue wires are needed for the flow of electrons. The black wire typically carries the live or "hot" current, while the blue wire is
neutral, completing the electrical circuit. The Green wire is the grounding or earth wire. It provides a safety mechanism by directing unwanted electricity safely to the ground, preventing
electric shocks or fire hazards if a fault occurs. The wire needs to be made out of a material that can transmit electric current. Such a material is called a conductor, and it is often a metal.
If a battery is linked to the wire, electrons always go from negative (-) to positive (+). On the other side the flow of electric current
goes in opposite direction. It goes from positive (+) to negative (-). It is important to know that no electrons go lost during the
process, otherwise we have a short circuit. But there are still possible reasons of loss of electrons, namely if there is a default in the
circuit or if someone is being electrocuted. The grounding wire (green wire) has the task to detect a leak and stopping the process
(security mechanism). When there is no power/battery linked to the wire, electrons are moving freely and in random directions in
the wire. This is the reason why metals are great conductors, because of freely moving electrons.
The reason why a metal is a possible good conductor is because of ‘the free valence electron’ on the last shelf of the atom. It is easy to take that electron away of the atom. When
you put a battery, the battery makes the electrons move in different directions. When electron A goes away from its molecule, electron B can easily take the place of electron A,
and this is happening in a chain reaction. The free valance elektron on the last chell of an atom are jumping from one atom to another atom.
To know if an element is a great conductor, you need to look at the resistivity of the element or metal. It gives how easy an atom will move, how strongly does the material resists
to electric current. The resistivity is expressed in ‘Ohms’.
Resistance is occurring because of the friction of some electrons in the wire. Those frictions cause the creation of heat. The friction of electrons can be caused because the wire is
too thin. So, a possible solution to this problem is to have a thicker wire.
It is also important to know that the resistivity depends on the temperature. They are positively correlated. If one increases, the other one increases also. When 2500 °C is
reached, a steady point is attained. The resistivity will not change anymore. When the temperature is that low (-273 °C) that there is no resistivity, we have superconductivity.
𝑰
The drift speed of an electron is the average velocity that a free electron in a conductor (like copper wire) attains due to an electric field. 𝒖 =
𝒏𝑨𝒒
◊ Electric Current (I) = Find it by using: Power: P = V . I ◊ n = # free electrons = Avogadro number (6.022×1023 atoms) . (density of wire/ atomic weight (in mol/m3))
◊ A = cross section area of the wire in m2 (𝝅 . r2) ◊ q = carried charge of 1 electron in coulomb (C) (dependent on # electrons and positive)
Direct Current (DC) vs Alternate Current (AC)
Direct Current (DC) has been created by Thomas Edison. He has created DC thanks to the dynamo machine. The original dynamo has been created by Zénobe Gramme. The
machine that Edison created, had the same mechanism but was more advanced in terms of efficiency and durability.
Before the creation of electro-mechanical generators, people relied on piles, which where stocks of dissimilar metals separated by electrolytes to produce small amounts of
electricity through chemical reactions. Piles was the first form of public lightening. The pile has been created by Volta.
Working of the Carbon Arc Lamp: In a carbon arc lamp, the electrodes are carbon sticks in free air. To lighten the lamp, the sticks are touched together, thus allowing a relatively
low voltage to strike the arc. The sticks are then slowly drawn apart, such that plasma is created, and electric current heats and maintains an arc across the gap. During the jump
of the electrons, friction is happening, this creates heath and when the heath is high enough, we can see photons.
Working of the Dynamo: It is an electrical generator that generated DC electricity by rotating a coil of wire within a magnetic field. A dynamo converts mechanical rotation into
electric power. Dynamo is a device that makes direct current electric power using electromagnetism.
This shows us the four fundamental states of matter
The alternate current has been created by Nikola Tesla
Working of the Tesla’s Alternator: Tesla’s alternator is an electromechanical device that converts mechanical energy into electrical energy in the form of alternating current (AC)
using electromagnetic induction. In hydroelectric power stations, such as the Niagara Falls power plant, the mechanical movement of a turbine is converted into electricity. The
turbine, driven by the kinetic energy of flowing water, spins and is connected to a rotor within a generator. As the turbine spins the rotor, electromagnetic induction occurs,
generating electricity. The idea of electromagnetic induction is that when a magnet is being spined besides a wire it produces an alternating current since electrons are appealed
to move in the wire. Depending on which pole of the magnet is besides the coil another direction will be given to the current.
Direct current is a type of electrical current where the direction of current flow remains constant over time. Friction from looped continuous
chain motion. In reality, the amplitude for direct current is not perfectly constant. It can increase or decrease just a little bit.
Alternating current is a type of electrical current where the direction of current flow alternates periodically. Friction from back-and-forth
alternating blade motions. In reality, the amplitude for alternate current is not always exactly equal (the amplitude moves a bit, but not too much)
ð Alternate Current (AC) has a moment where the electrons are not in motion while the electrons in a Direct Current (DC) are always in motion.
Direct Current (DC) in practical
An ammeter is an electrical instrument used to measure the flow of electric current in a circuit by detecting the strength of a magnetic field generated by the current passing
through a coil inside the device. A voltmeter is an electrical instrument used to measure the potential electromotive force, and it’s placed in parallel with the circuit elements
whose voltage you want to measure. An ideal voltmeter has a very high internal resistance to ensure that it draws minimal current from the circuit it is measuring.
The voltage drops across a resistor as a result of the resistor consuming power due to the current flowing through it. The electric current in a system is always the same, but the
volateg can differ. This will be discussed later with the Kirchhoff’s Laws.
, Components of an electric circuit – Resistor, Capacitor and Inductor
A resistor is an electrical component designed to limit the flow of electric current in a circuit (the speed of electrons remains the same). It does this by introducing
resistance. They can be used to control current by lowering it to safe levels and to create a voltage drop to divide voltage in a circuit.
è Series: bulb with higher resistance (lower wattage rating) will glow brighter than low resistance bulb. In series use formula P = (I2) . R, where I is constant.
è Parallel = bulb with lower resistance (higher wattage rating bulb) will glow brighter than high resistance bulb. In parallel use formula P= (V2)/R, where V is constant
A capacitor is an electronic component used to store and release electrical energy in a circuit. It consists of two conductive plates separated by an insulating material
called a dielectric. It is useful for short-term energy storage, voltage smoothing, signal filtering, ...
An inductor is an inductor is an electronic component used to store and release electrical energy in the form of a magnetic field. It consists of a coil of wire wound
around a core material, such as iron or ferrite. It is useful for filtering, longer term energy storage, and signal conditioning in electronic circuits.
Working of a Capacitor: The latter is composed out of 2 electrically conductive plates separated by a dielectric (a non-conductive substance such as air) that insulate them. When
a voltage is applied across the two plates of the capacitor, an electric field is established between them. The positive charge accumulates on one plate, while the negative charge
accumulates on the other plate. This creates an electric potential difference (voltage) between the plates. When the voltage source is removed or the capacitor is connected to a
load (such as a lamp), it discharges, releasing the stored energy back into the circuit. Electrons flow through the circuit to equalize the charge on both plates, thereby discharging
the capacitor.
Working of a Lithium Battery: We will make use of a ‘third’ dimension to ‘park’/store more electrons into a smaller place. That is what lithium batteries are used for. Between two
metallic plates, we will put a thin sheet of paper to prevent the two metallic plates having contact with each other. The sandwich is going to be rolled and that’s why most
capacitors are in a cylindrical form. The working of it is exactly the same as the explanation about how a capacitor works because a battery is a capacitor (it stores electricity).
è But it lithium batteries are not good for the environment. They have a big impact on the environment. Lithium is a raw material that is very limited.
Working of a Pump Hydroelectric Storage Facility (Coo I): When too much energy is created by Tihange II, the water of
the low basin will be pumped into to higher layed basin. This happens with the motor. When the demand is higher than
the amount of energy that is produced by Tihange II, then the water of the higher basin will be released and create
energy. This happens with the dynamo. Keep in mind, the turbine works as a dynamo and motor (same machine!) but
working in opposite directions. This gives the opportunity to use energy know to recreate it later when needed.
è You can calculate the resistance of a resistor based on its colour codes !
High Voltage Direct Current (HVDC) transmission
The wind turbines generate a lot of electric current in Alternate Current. This current will be transferred to a terminal, where it will be transformed by a transformer into Direct
Current, more specifically in HVDC. This HVDC will be transferred to another region’s/country’s terminal, where it will be transformed again into Alternate Current. This current is
used to supply the local households. The current can finally be distributed to households.
è HVDC is being used to transfer electric current from one region to another in the most effective way and also the most costefficient way
The long distance happens with Direct Current because it is cheaper. Direct Current only needs one wire while Alternate Current need more
wires. But the costs for the terminals is way higher for Direct Current. A cost analysis needs to be made to decide whether Alternate Current or
Direct Current is the best option. For short distances the Alternate Current line cost is lower than the Direct Current line cost, so the Alternate
Current will be implemented. For long distances (past the critical distance) the Alternate Current line cost is higher than the Direct Current line
cost, so the Direct Current will be implemented.
A power transformer is an electrical device used to transfer energy between 2 or more circuits through electromagnetic induction, it is commonly used to change the voltage
levels of AC electricity. When AC flows through the primary coil, it creates a changing magnetic field in the transformers core. This change in magnetic field induces a voltage in
the secondary coil, which is then transferred to the load. A transformer works only with AC, because with DC the induced magnetic field around the wire will remain constant
while you need a changing magnetic field to induce another voltage in the secondary coil. The size of the induced voltage depends on the number of turns on each coil (if there
are less in the secondary coil, the voltage falls). The core is there to prevent waste of electromagnetic field when inducing the voltage.
The Kirchhoff’s Laws
The Kirchhoff’s Current Law (KCL) is that the intensity (amperes) entering a junction is equal to the current leaving that junction. If there are two branches (i2 and i3)
who are going to a junction and there are two branches (i1 and i4) who go away from the junction, than i2 + i3 = i1 + i4
The Kirchhoff’s Voltage Law (KVL) is that the deferences n potential electromotive forces (volts) within a circuit sum up to 0. The whole energy is being consumed during
the circuit.
Exercises à
A cable is composed out of 3 different wires. The Black and Blue wires are needed for the flow of electrons. The black wire typically carries the live or "hot" current, while the blue wire is
neutral, completing the electrical circuit. The Green wire is the grounding or earth wire. It provides a safety mechanism by directing unwanted electricity safely to the ground, preventing
electric shocks or fire hazards if a fault occurs. The wire needs to be made out of a material that can transmit electric current. Such a material is called a conductor, and it is often a metal.
If a battery is linked to the wire, electrons always go from negative (-) to positive (+). On the other side the flow of electric current
goes in opposite direction. It goes from positive (+) to negative (-). It is important to know that no electrons go lost during the
process, otherwise we have a short circuit. But there are still possible reasons of loss of electrons, namely if there is a default in the
circuit or if someone is being electrocuted. The grounding wire (green wire) has the task to detect a leak and stopping the process
(security mechanism). When there is no power/battery linked to the wire, electrons are moving freely and in random directions in
the wire. This is the reason why metals are great conductors, because of freely moving electrons.
The reason why a metal is a possible good conductor is because of ‘the free valence electron’ on the last shelf of the atom. It is easy to take that electron away of the atom. When
you put a battery, the battery makes the electrons move in different directions. When electron A goes away from its molecule, electron B can easily take the place of electron A,
and this is happening in a chain reaction. The free valance elektron on the last chell of an atom are jumping from one atom to another atom.
To know if an element is a great conductor, you need to look at the resistivity of the element or metal. It gives how easy an atom will move, how strongly does the material resists
to electric current. The resistivity is expressed in ‘Ohms’.
Resistance is occurring because of the friction of some electrons in the wire. Those frictions cause the creation of heat. The friction of electrons can be caused because the wire is
too thin. So, a possible solution to this problem is to have a thicker wire.
It is also important to know that the resistivity depends on the temperature. They are positively correlated. If one increases, the other one increases also. When 2500 °C is
reached, a steady point is attained. The resistivity will not change anymore. When the temperature is that low (-273 °C) that there is no resistivity, we have superconductivity.
𝑰
The drift speed of an electron is the average velocity that a free electron in a conductor (like copper wire) attains due to an electric field. 𝒖 =
𝒏𝑨𝒒
◊ Electric Current (I) = Find it by using: Power: P = V . I ◊ n = # free electrons = Avogadro number (6.022×1023 atoms) . (density of wire/ atomic weight (in mol/m3))
◊ A = cross section area of the wire in m2 (𝝅 . r2) ◊ q = carried charge of 1 electron in coulomb (C) (dependent on # electrons and positive)
Direct Current (DC) vs Alternate Current (AC)
Direct Current (DC) has been created by Thomas Edison. He has created DC thanks to the dynamo machine. The original dynamo has been created by Zénobe Gramme. The
machine that Edison created, had the same mechanism but was more advanced in terms of efficiency and durability.
Before the creation of electro-mechanical generators, people relied on piles, which where stocks of dissimilar metals separated by electrolytes to produce small amounts of
electricity through chemical reactions. Piles was the first form of public lightening. The pile has been created by Volta.
Working of the Carbon Arc Lamp: In a carbon arc lamp, the electrodes are carbon sticks in free air. To lighten the lamp, the sticks are touched together, thus allowing a relatively
low voltage to strike the arc. The sticks are then slowly drawn apart, such that plasma is created, and electric current heats and maintains an arc across the gap. During the jump
of the electrons, friction is happening, this creates heath and when the heath is high enough, we can see photons.
Working of the Dynamo: It is an electrical generator that generated DC electricity by rotating a coil of wire within a magnetic field. A dynamo converts mechanical rotation into
electric power. Dynamo is a device that makes direct current electric power using electromagnetism.
This shows us the four fundamental states of matter
The alternate current has been created by Nikola Tesla
Working of the Tesla’s Alternator: Tesla’s alternator is an electromechanical device that converts mechanical energy into electrical energy in the form of alternating current (AC)
using electromagnetic induction. In hydroelectric power stations, such as the Niagara Falls power plant, the mechanical movement of a turbine is converted into electricity. The
turbine, driven by the kinetic energy of flowing water, spins and is connected to a rotor within a generator. As the turbine spins the rotor, electromagnetic induction occurs,
generating electricity. The idea of electromagnetic induction is that when a magnet is being spined besides a wire it produces an alternating current since electrons are appealed
to move in the wire. Depending on which pole of the magnet is besides the coil another direction will be given to the current.
Direct current is a type of electrical current where the direction of current flow remains constant over time. Friction from looped continuous
chain motion. In reality, the amplitude for direct current is not perfectly constant. It can increase or decrease just a little bit.
Alternating current is a type of electrical current where the direction of current flow alternates periodically. Friction from back-and-forth
alternating blade motions. In reality, the amplitude for alternate current is not always exactly equal (the amplitude moves a bit, but not too much)
ð Alternate Current (AC) has a moment where the electrons are not in motion while the electrons in a Direct Current (DC) are always in motion.
Direct Current (DC) in practical
An ammeter is an electrical instrument used to measure the flow of electric current in a circuit by detecting the strength of a magnetic field generated by the current passing
through a coil inside the device. A voltmeter is an electrical instrument used to measure the potential electromotive force, and it’s placed in parallel with the circuit elements
whose voltage you want to measure. An ideal voltmeter has a very high internal resistance to ensure that it draws minimal current from the circuit it is measuring.
The voltage drops across a resistor as a result of the resistor consuming power due to the current flowing through it. The electric current in a system is always the same, but the
volateg can differ. This will be discussed later with the Kirchhoff’s Laws.
, Components of an electric circuit – Resistor, Capacitor and Inductor
A resistor is an electrical component designed to limit the flow of electric current in a circuit (the speed of electrons remains the same). It does this by introducing
resistance. They can be used to control current by lowering it to safe levels and to create a voltage drop to divide voltage in a circuit.
è Series: bulb with higher resistance (lower wattage rating) will glow brighter than low resistance bulb. In series use formula P = (I2) . R, where I is constant.
è Parallel = bulb with lower resistance (higher wattage rating bulb) will glow brighter than high resistance bulb. In parallel use formula P= (V2)/R, where V is constant
A capacitor is an electronic component used to store and release electrical energy in a circuit. It consists of two conductive plates separated by an insulating material
called a dielectric. It is useful for short-term energy storage, voltage smoothing, signal filtering, ...
An inductor is an inductor is an electronic component used to store and release electrical energy in the form of a magnetic field. It consists of a coil of wire wound
around a core material, such as iron or ferrite. It is useful for filtering, longer term energy storage, and signal conditioning in electronic circuits.
Working of a Capacitor: The latter is composed out of 2 electrically conductive plates separated by a dielectric (a non-conductive substance such as air) that insulate them. When
a voltage is applied across the two plates of the capacitor, an electric field is established between them. The positive charge accumulates on one plate, while the negative charge
accumulates on the other plate. This creates an electric potential difference (voltage) between the plates. When the voltage source is removed or the capacitor is connected to a
load (such as a lamp), it discharges, releasing the stored energy back into the circuit. Electrons flow through the circuit to equalize the charge on both plates, thereby discharging
the capacitor.
Working of a Lithium Battery: We will make use of a ‘third’ dimension to ‘park’/store more electrons into a smaller place. That is what lithium batteries are used for. Between two
metallic plates, we will put a thin sheet of paper to prevent the two metallic plates having contact with each other. The sandwich is going to be rolled and that’s why most
capacitors are in a cylindrical form. The working of it is exactly the same as the explanation about how a capacitor works because a battery is a capacitor (it stores electricity).
è But it lithium batteries are not good for the environment. They have a big impact on the environment. Lithium is a raw material that is very limited.
Working of a Pump Hydroelectric Storage Facility (Coo I): When too much energy is created by Tihange II, the water of
the low basin will be pumped into to higher layed basin. This happens with the motor. When the demand is higher than
the amount of energy that is produced by Tihange II, then the water of the higher basin will be released and create
energy. This happens with the dynamo. Keep in mind, the turbine works as a dynamo and motor (same machine!) but
working in opposite directions. This gives the opportunity to use energy know to recreate it later when needed.
è You can calculate the resistance of a resistor based on its colour codes !
High Voltage Direct Current (HVDC) transmission
The wind turbines generate a lot of electric current in Alternate Current. This current will be transferred to a terminal, where it will be transformed by a transformer into Direct
Current, more specifically in HVDC. This HVDC will be transferred to another region’s/country’s terminal, where it will be transformed again into Alternate Current. This current is
used to supply the local households. The current can finally be distributed to households.
è HVDC is being used to transfer electric current from one region to another in the most effective way and also the most costefficient way
The long distance happens with Direct Current because it is cheaper. Direct Current only needs one wire while Alternate Current need more
wires. But the costs for the terminals is way higher for Direct Current. A cost analysis needs to be made to decide whether Alternate Current or
Direct Current is the best option. For short distances the Alternate Current line cost is lower than the Direct Current line cost, so the Alternate
Current will be implemented. For long distances (past the critical distance) the Alternate Current line cost is higher than the Direct Current line
cost, so the Direct Current will be implemented.
A power transformer is an electrical device used to transfer energy between 2 or more circuits through electromagnetic induction, it is commonly used to change the voltage
levels of AC electricity. When AC flows through the primary coil, it creates a changing magnetic field in the transformers core. This change in magnetic field induces a voltage in
the secondary coil, which is then transferred to the load. A transformer works only with AC, because with DC the induced magnetic field around the wire will remain constant
while you need a changing magnetic field to induce another voltage in the secondary coil. The size of the induced voltage depends on the number of turns on each coil (if there
are less in the secondary coil, the voltage falls). The core is there to prevent waste of electromagnetic field when inducing the voltage.
The Kirchhoff’s Laws
The Kirchhoff’s Current Law (KCL) is that the intensity (amperes) entering a junction is equal to the current leaving that junction. If there are two branches (i2 and i3)
who are going to a junction and there are two branches (i1 and i4) who go away from the junction, than i2 + i3 = i1 + i4
The Kirchhoff’s Voltage Law (KVL) is that the deferences n potential electromotive forces (volts) within a circuit sum up to 0. The whole energy is being consumed during
the circuit.
Exercises à
