♥Basic Electronics♥

T.L.E. 90

Electronics - is the branch of science and technology which makes use of the controlled motion of electrons through different media and vacuum. The ability to control electron flow is usually applied to information handling or device control.

Atom - is a basic unit of matter that consists of a dense, central nucleus surrounded by a cloud of negatively charged eletrons.

Eletrons - is a subatomic particle carrying a negative electric charge. It has no known components or substructure, and elementary particle. Protons is a subatomic particle with an electric charge of +1 elementary charge. Neutrons is a subatomic particle with no net electric charge and a mass slightly larger than of a proton.

Matter- is a general term for the substance of which all physical objects are made includes atoms and particles which have mass. Matter is commonly said to exist in four states: solid,liquid, gas and plasma.

Sources of voltage:

*Chemical- battery

*Photoelectric- solid

*Generator- magnetisn

*Thermocouple(heat)

Types of Current

Direct Current - the flow of electric charge is only in one direction.

Alternating Current - the movement of electric charge periodically reverses direction.

Pulsating Direct Current - is a direct current that changes in value at regular or irregular intervals.

Ohm's law - states that the current through a conductor between two points is directly proportional to the potentail difference or voltage across the two points, and inversely proportional to the resistance between them.

The mathematical equation that describes this relationship is:

where V is the potential difference measured across the resistance in units of volts; I is the current through the resistance in units of amperes and R is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of the current.

The law was named after the German physicist George Ohm who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire. He presented a slightly more complex equation than the one above to explain his experimental results. The above equation is the modern form of Ohm's law.

In physics, the term Ohm's law is also used to refer to various generalizations of the law originally formulated by Ohm. The simplest example of this is:

where J is the current density at a given location in a resistive material, E is the electric field at that location, and σ is a material dependent parameter called the conductivity . This reformulation of Ohm's law is due to Gustav Kirchhoff.

Power supply - is a supply of electrical power. A device or system that supplies electrical or other types of energy to an output load or group of loads is called a power supply unit or PSU. The term is most commonly applied to electrical energy supplies, less often to mechanical ones, and rarely to others.

A power supply may include a power distribution system as well as primary or secondary sources of energy such as:

• Conversion of one form of electrical power to another desired form and voltage, typically involving converting AC line voltage to a well-regulated lower-voltage DC for electronic devices. Low voltage, low power DC power supply units are commonly integrated with the devices they supply, such as computers and household electronics.
• Batteries
• Chemical fuel cells and other forms of energy storage systems
• Solar power
• Generators or alternators

Constraints that commonly affect power supplies are the amount of power they can supply, how long they can supply it without needing some kind of refueling or recharging, how stable their output voltage or current is under varying load conditions, and whether they provide continuous power or pulses.

A regulated power supply is one that includes circuitry to tightly control the output voltage and/or current to a specific value. The specific value is closely maintained despite variations in the load presented to the power supply's output, or any reasonable voltage variation at the power supply's input.

Regulated Power supply

Am receiver - is an electronic circuit that receives its input from an antenna , uses electronics to separate a wanted radio signal from all other signals picked up by this antenna, amplifies it to a level suitable for further processing, and finally converts through demodulation the signal into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc.

In consumer electronics, radio receiver are often used specifically for receivers designed for the sound signals transmitted by radio broadcasting services – historically the first mass-market radio application.