Electronics And Digital Electronics

BASIC ELECTRONIC COMPONENTS

CURRENT

An electric current is a flow of electric charge(Negative Electrons). Electric charge flows when there is voltage present across a conductor.   current is measured in AMPS and resistance is measured in OHMS.

Direct current

Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric charge flows in a constant direction, distinguishing it from alternating current (AC).

 

Alternating current

In alternating current (AC, also ac), the movement of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge is only in one direction.

AC is the form in which electric power is delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave. In certain applications, different waveforms are used, such as triangular or square waves. Audio and radio signals carried on electrical wires are also examples of alternating current. In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.

VOLTAGE

Voltage, electrical potential difference, electric tension or electric pressure is the electric potential difference between two points, or the difference in electric potential energy of a unit charge transported between two points.^[1] Voltage is equal to the work done per unit charge against a static electric field to move the charge between two points. A voltage may represent either a source of energy (electromotive force), or lost, used, or stored energy (potential drop). A voltmeter can be used to measure the voltage (or potential difference) between two points in a system; usually a common reference potential such as the ground of the system is used as one of the points.

WATT

Electrical power is measured in watts. In an electrical system power (P) is equal to the voltage multiplied by the current.


VOLTAGE (VOL) * CURRENT (AMPS) = WATT






RESISTORS

The electronic component known as the resistor is best described as electrical friction. Pretend, for a moment, that electricity travels through hollow pipes like water. Assume two pipes are filled with water and one pipe has very rough walls. It would be easy to say that it is more difficult to push the water through the rough-walled pipe than through a pipe with smooth walls. The pipe with rough walls could be described as having more resistance to movement than the smooth one

 

Pioneers in the field of electronics thought electricity was some type of invisible fluid that could flow through certain materials easily, but had difficulty flowing through other materials. In a way they were correct since the movement of electrons through a material cannot be seen by the human eye, even with the best microscopes made. There is a similarity between the movement of electrons in wires and the movement of water in the pipes. For example, if the pressure on one end of a water pipe is increased, the amount of water that will pass through the pipe will also increase. The pressure on the other end of the pipe will be indirectly related to the resistance the pipe has to the flow of water. In other words, the pressure at the other end of the pipe will decrease if the resistance of the pipe increases.

 

Electrons flow through materials when a pressure (called voltage in electronics) is placed on one end of the material forcing the electrons to “react” with each other until the ones on the other end of the material move out. Some materials hold on to their electrons more than others making it more difficultfor the electrons to move. These materials have a higher resistance to the flow of electricity (called current in electronics) than the ones that allow electrons to move easily. Therefore, early experimenters called the materials insulators if they had very high resistance to electron flow and conductors if they had very little resistance to electron flow. Later materials that offered a medium amount of resistance were classified as semiconductors

 CAPACITORS
 

 INDUCTORS

 

 SEMICONDUCTORS

 
 

Applications of Electromagnetic Energy with Semiconductors

Relating to the interrelation of electric currents or fields and magnetic fields.  Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each traveling in a wave-like pattern at the speed of light. Each photon contains a certain amount of energy. The different types of radiation are defined by the the amount of energy found in the photons. Radio waves have photons with low energies, microwave photons have a little more energy than radio waves, infrared photons have still more, then visible, ultraviolet, X-rays, and, the most energetic of all, gamma-rays.

Light and Photons

 “An electron has a natural orbit that it occupies, but if you energize an atom you can move its electrons to higher orbitals [shells]. A photon of light is produced whenever an electron in a higher-than-normal orbit falls back to its normal orbit. During the fall from high-energy to normal-energy, the electron emits a photon -- a packet of energy -- with very specific characteristics. The photon has a frequency, or color, that exactly matches the distance the electron falls.”

     A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation, and the force carrier for the electromagnetic force, even when static via virtual photons. The effects of this force are easily observable at both the microscopic and macroscopic level, because the photon has zero rest mass; this allows long distance interactions. Like all elementary particles, photons are currently best explained by quantum mechanics and exhibit wave–particle duality, exhibiting properties of both waves and particles. For example, a single photon may be refracted by a lens or exhibit wave interference with itself, but also act as a particle giving a definite result when its position is measured.

Atoms, Electrons and Photons

Important terms

• Proton
• A positively charged atomic element
• Neutron
• A neutrally charged atomic element
• Nucleus
• The center of an atom, composed of the proton(s) and the neutron(s)
• Electron
• A negatively charged atomic element that orbits the nucleus
• Electron shell
• The orbital level(s) that an electron can occupy
• Electromagnetic force
• One of the four fundamental forces of nature that binds electrons to the nucleus
• Photon
• The basic unit of light and the force carrier for the electromagnetic force
• Ion
• An atom that has either gained or lost an electron, causing the atom to become either negatively or positively charged, respectively

The electron is responsible for chemical bonding where electrons are shared between atoms to create molecules.

Measuring electromagnetic radiation

Electromagnetic radiation can be expressed in terms of energy, wavelength, or frequency. Frequency is measured in cycles per second, or Hertz. Wavelength is measured in meters. Energy is measured in electron volts.

How the Electromagnetic radiation are produced

When a direct electrical current is applied to a wire the current flow builds an electromagnetic field around the wire. This field sends a wave outward from the wire. When the current is removed, the field collapses which again sends a wave. If the current is applied and removed over and over for a period of time, a series of waves is propagated at a discrete frequency. If the current changes polarity, or direction repeatedly, that could make waves, too.

Example: How is data put on radio waves?

Basics of Computer Hardware

 

Information Representation:

 Internal Electronic circuits(Transistor) works like our electrical circuit in our home as below. 

 

 

 

 

 

In the below transistor illustration, there is no power supply pass through into this transistor, which means it is in OFF state.  if we switch on the power supply then it will be ON state

 

 

 

 

 

 

 

 

Computer needs transistor for below operations

 

 

 

 Human decimal system uses below number system to identify numbers

 

 

  Computer used below BINARY system to recognize numbers

 

 

 

 

 

 

 

The reason why computer scientist groups all the bits as a byte (8 bit) is to avoid false start and finish problem during storage representation of data in memory.  So solution is grouping bits as a byte like below.

  How computer stores Colors, images, Audio and video

 

  Computer stores everything as a numbers inside of its memory

 

 

 

  Computer represents TEXT data in ASCII or UNICODE format which is universal standards

 

 

 

 

 

Computation of Computer

 

  Logic gates are used to perform calculations in computer through CPU...All the logic gates are formed based on the alignments of transistors.

 

 

 

 

 

 

 

 

 

 

 

 

Below is Adder Logic gates to add two bits

 

 

 

 

 

 Carry bit problem

Carry bit problem in BINARY addition

 

 

  

Carry bit problem in DECIMAL addition

 

 

Logic gates handle Carry bit problem as below

 

 

 

Below logic gate circuits joint together to perform large numbers calculation

 

 

 Lot of logic gates circuit are formed to perform below works in computer CPU

 

 

 

 

 Microprocessor executes program from memory with FETCH commands as below

 

 

 

 

 

 

 

 

 

 

 

 

 

Computer Programming

 

Below instructions are human readable program but computer only understands Machine language.

 

 

 

 Programmer only writes program with Mnemonic keyword, but computer decodes these Mnemonic word as Microprocessor execute code to process instructions

 

 Even today computer programs are sequence of bits and bytes and stored in computer memory for execution.  In early days, programmer had to insert these sequence of bits into memory to execute simple program.  As it was very tedious process, computer scientist invented High Level programming language.

 

 

 

 Operation system is set of programs and library which helps user interact with computer through keyboard, mouse and Screen.  This will stand in between hardware and users' programs to facilitate user to execute their instructions without any difficulties.