Basic concept of Electronics
This write-up focusses on the Basic concept of Electronics. Understanding the concepts in Electronics involves so many mathematical formulas and equations But in this Course we will ignore them but come from an approach that will make it easy to understand and apply these concepts in designs of Electronic Circuits.
Electric Current:
In simple terms when an electronic device is powered ,electric currents begins to flow and this gives life to the system. For example when a current source such as the battery is put into a wall clock, current flows from the battery and gives life to the clock, this is applicable in all other electronics devices.
Current is the rate of flow of electric charge past a point. It is also the total charge that passes through some cross- sectional area A of Conductor per unit time.. By convention, current in a circuit is considered to flow from a more positive point to a more negative point, even though the actual electron flow is in the opposite direction. The flow of electricity per second is measured in amperes (A) , or amps
There are two types of current which are:
- Alternating Current (AC)
- Direct Current (DC)
Direct and alternating current
The flow of current that you get from a battery is known as direct current, or DC. Like the flow of water from a faucet, it is a steady stream, in one direction. The flow of current that you get from the “hot” OR "Live" wire in a power outlet/Socket in your home is very different. It changes from positive to negative 50 times each second (in Great Britain and some other nations, 60 times per second). This is known as alternating current, or AC, which is more like the pulsatile flow you get from a power washer. Alternating current is essential for some purposes, such as cranking up voltage so that electricity can be distributed over long distances. AC is also useful in motors and domestic appliances. In this Article I’m going to be talking about DC unless otherwise noted. For two reasons: first, most simple electronic circuits are powered with DC, and second, the way it behaves is much easier to understand.
Voltage:
This is the Force that pushes current out of a battery or other power sources.
To get electrical current to flow from one point to another, a voltage must exist between the two points. A voltage placed across a conductor gives rise to an electromotive force (EMF) that is responsible for giving all free electrons within the conductor a push.
The voltage between two points is the cost in energy (work done) required to move a unit of positive charge from the more negative point (lower potential) to the more positive point (higher potential).
Voltage is also called potential difference or electromotive force (EMF).
Voltage can either be AC or DC. its unit is volt (V).
RESISTANCE:
This is the opposition to the flow of current in an electric circuit and is is achieved with the use of an electronic circuit known as a resistor (resistors will be discussed in next post).
Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). Ohms are named after Georg Simon Ohm (1784-1854), a German physicist who studied the relationship between voltage, current and resistance. He is credited for formulating Ohm's Law.
Relationship Between Electric Current, Voltage and Resistance
As seen in the above image, the Voltage applied to the system pushes the current to flow in the circuit but the resistance (in ohms) limits the current flow so as to restrict the flow of electricity and protect the components in the circuit. We should also note the resistance in a circuit generates heat in the circuit.
CAPACITANCE:
Capacitance is the ability of a component or circuit to collect and store energy in the form of an electric charge. This is achieved with an electronic component known as a capacitor. There are times in which electrical energy is to be stored for a period of time, as will be discussed later in this course there will be a need for a capacitor to store the electric energy.
INDUCTANCE:
Inductance is the ability of an inductor to store energy and it does this in the magnetic field that is created by the flow of electrical current .This is achieved with an electronic component called an Inductor. Just as a capacitor stores electric charges in an electric field, inductors store electric charges in a magnetic field
Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. This means that whenever an inductor is placed in an electric circuit, if there is a change in the electric current flowing through it (i.e. there is instability in the current flow), it tries to oppose the current flow but if the electric current flow is stable as in a DC system, the inductor acts as a normal wire.
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