Understanding Electric Current and Circuits: A Comprehensive Guide
Electric current:
Is the continuous flow of electrons.
Conductors:
Materials that allow electric current to pass through them.
Insulators:
Materials that do not allow electric current to pass through them.
Static electricity:
Is the result of an imbalance between negative and positive charges in an object.
Electric circuit:
Is a set of connected components through which an electric current circulates.
Generators:
Provide the necessary energy to move the electrons. (Batteries: use chemical processes to generate or to hold electric current. Alternators or dynamos: transform motion into electric current. Photovoltaic solar cells: use energy from the sun to generate electric current. Hydrogen cells: produce energy from the oxygen in the air and hydrogen.)
Receptors:
Components that transform electrical energy into another type of energy. (Electric resistors, bulbs, motors, bells)
Conductors:
Elements that join all the components of a circuit and allow the flow of electric current through them. (Cables, wires)
Power and energy:
Is the amount of energy produced per second. Electrical energy can be transformed into light, heat, or mechanical energy. P = ET. Power is measured in watts (W). Energy is measured in joules (J). Time is measured in seconds (S). Electrical energy can be measured in kilometres per hour (KM/H)
Ohm’s law:
The first scientist to study the relationship between voltage, current and resistance was George Ohm, who in 1822 carried out an experiment to discover it.
Control components:
They stop, start or change the directions of the electric current. (Switch: it has 2 positions. One that allows the flow of electric current and the other stops it. Circular switch: it has 2 outputs, so it communicates with 2 different circuits allowing the current to go one way or the other depending on its position. Push button: it has a fixed position that changes when it’s pressed. It returns to its position when we let it go.)
Protection components:
Stop the current when it’s too strong so that the important components of the circuit are not damaged. (Fuse: protect the equipment from short circuit damage. Magnethotermic circuit breakers: this type of element includes two electrical protection systems. One thermal and one magnetic. Electric differential: device that quickly breaks the electrical circuit to prevent harm from an ongoing electric shock.)
Representation symbols:
If we want to represent an electric circuit on paper, we use a diagram. A diagram: is a graphic representation using symbols for the components of the circuits. These symbols are easy to draw and follow.
Resistance:
Is the opposition of the components in a circuit to the flow of electric current. It is represented by the letter R and is measured in ohms. We use an ohmmeter to measure it, by connecting it in parallel to the element you want to measure. You have to disconnect all the generators of the circuit.
Effects of an electric current:
Energy in an electric current has different effects on the receptors and can be transformed into other types of energy. (Heat: the elements that we use to produce heat are called resistors. We obtain heat when the conductor is thin, and the electrons try to pass and there is a lot of collisions between them. In each collision, part of the energy that they are carrying is transformed into heat. Light: the object increases its temperature and this makes light appear. First, it’s red, then orange, then yellow, and finally, it becomes white. Incandescent bulbs are based on this phenomenon. Some gases emit light when the electrons move inside (fluorescent tubes/ low energy bulbs). When the electrons flow through the electronic component called LED, it emits light. Motion: the element that creates motion using electricity is called a motor. They are based on the forces of attraction and repulsion between a magnet and a conductor wire placed inside it.)
Electric quantities:
Is the charge is the amount of electricity stored in an object. It is represented by the letter Q and is measured in coulombs.
Voltage:
Difference between electrical energy at two points in a circuit. The charge always moves from the point with the highest energy. It is represented by the letter V and is measured in volts. We use a voltmeter to measure it, by connecting it in parallel to the component/generator.
Current:
Is the number of electrons that pass through a specific point in one second. It is represented by the letter I and is measured in amperes. We use an ammeter to measure it, by connecting it in series to the receptor you want to measure.