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1.Electric charge, Photovoltaic solar cells, Measuring instruments, 2…
1.Electric charge
1.1 Generalities: All matter of very small particles called atoms. We do not know exactly what they look like, but we have models of how we imagine them to be.
we distinguis two parts, a nucleus which, constitute most of the atom's mass and is composed of protons ad neutrons (potives and neutral charge)
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Photovoltaic solar cells
They are
increasingly more common. They
can be classified as very
ecological as they take energy
from sunlight with no emissions
during use
Hydrogen cells
They produce
energy from oxygen in the air and
hydrogen. They are not yet
common as they are still in
development. They are potentially
very ecological as they only
produce water as waste
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Measuring instruments
A voltmeter measures the electrical voltage. To
measure the voltage of a component you connect
the voltmeter as shown in the image (in parallel). The
internal resistance of the device is very high, so
hardly any current flows through it. You only need a
few electrons to measure voltage
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2.Electric current
In the previous example whit the pen, the are at rest. They don’t
move through the electrified material. This is called static electricity.
However, just as water can flow through a tube, electrons can move
through certain materials and create an electric current
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3. Electric circuits
An electric current is several electrons that flow through a conductor like
water flows through a tube. This comparison is useful to understand how
electric circuit works
An electric sircuit is a set of connected components through which an
electric current circulates. It is composed of:
- A generator, a wire conector, a switch(to open or close the circuit), a receptor(a lightbulb, a motor, a resistor, etc)
Generators
A generator provides the energy necesary to move the electrons. It produces a continuous electric current. We can distinguish four types the generator.
Alternators or dynamos
They are
very common. They transform
motion into electric current. They
can be classified as medium-high
environmentally friendly, since they
are efficient but depends on the
energy source driving them
Receptor
In a circuit, the receptors are the components that transform electrical
energy into another type of energy like heat, light, motion or even sound.
The electrons leave the generator, taking the energy with them and move
round the circuit until they get back to the opposite terminal (closed circuit)
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Motion
Motors transform electrical energy into motion. They are based on the
forces of attraction and repulsion between a magnet and a conductor
wire placed in one or more loops inside it. The electric current flows
through the conductor wire
6.Electric quantities
The basic electric quantities are voltage, current, and resistance
6.1 Voltage, current and resistance
We call charge to the amount of electricity stored in an object. It is the
equivalent of volume of water in the container. It is usually represented by
letter Q and is measured in coulombs [C]
7.Ohm's law
Georg Ohm was a German physicist who first studied the relationship
between voltage, current and resistance. Nowadays, the proportional
relationship between voltage, current and resistance is called Ohm’s law,
and is expressed mathematically as:
v = I * R
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