basics of electronics.docx

7/28/2019 basics of electronics.docx

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BASICS OF ELECTRONICS

An Electronic Component is a basic electronic element and may be available

in a discrete form having two or more electrical terminals (or leads). These are

intended to be connected together, usually by soldering to a printed circuit

board, in order to create an electronic circuit with a particular function (for

example an amplifier, radio receiver, or oscillator). Basic electronic components

may be packaged discretely or integrated inside of packages. The following list

of electronic components focuses on the discrete version of these components

treating such packages as components in their own right.

Fig. 1.1 Various Components.

CLASSIFICATION


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A Component may be classified as Passive or Active. The strict physics

definition treats passive components as ones that cannot supply energy

themselves; whereas a battery would be seen as an active component since it

truly acts as a source of energy.

PASSIVE COMPONENTSThey are ones which cannot introduce net energy into the circuit they are

connected to. They also cannot rely on a source of power except for what is

available from the (AC) circuit they are connected to. As a consequence they

are unable to amplify (increase the power of a signal); although they may

increase a voltage or current such as is done by a transformer or resonant

circuit. Passive components include two-terminal components such as resistors,

capacitors, inductors, and transformers. Passive Components Can Be Further

Divided Into Lossless and Lossy Components

ACTIVE COMPONENTS

Electronic

Components

Active

ComponentsPassive

Componenets


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They rely on a source of energy (usually from the DC circuit, which we have

chosen to ignore) and are usually able to inject power into a circuit. This

includes amplifying components such as transistors, triode vacuum tubes

(valves), and tunnel diodes.

ELECTRONICS COMPONENTS

1. TERMINALS AND CONNECTORS:Devices To Make Electrical Connection Are:

TERMINAL:

A Terminal is the point at which a conductor from an electrical network

comes to an end and provides a point of connection to external circuit. The

connection may be temporary, as for portable equipment, or may be required

as a tool for assembly and removal, or may be a permanent electrical joint

between two wires or devices.

CONNECTOR:o Socketo Screw terminal, Terminal Blockso Pin header

POWER CORD:
http://en.wikipedia.org/wiki/Terminal_%28electronics%29http://en.wikipedia.org/wiki/Electrical_connectorhttp://en.wikipedia.org/wiki/Screw_terminalhttp://en.wikipedia.org/wiki/Pin_headerhttp://en.wikipedia.org/wiki/Pin_headerhttp://en.wikipedia.org/wiki/Screw_terminalhttp://en.wikipedia.org/wiki/Electrical_connectorhttp://en.wikipedia.org/wiki/Terminal_%28electronics%29


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A Power Cord, Line Cord, or Mains Cable is a cable that temporarily

connects an appliance to the mains electricity supply via a wall socket or

extension cord. These terms generally use a power plug to connect to a single-

phase alternating current power source at the local line voltage (Generally 100

To 240 Volts, Depending On The Location). The terms Power Cable, Mains

Lead or Flex are also used. Power cables may be either fixed or detachable from

the appliance.

CABLE ASSEMBLIES: Cables with connectors or terminals at theirends.

2. RESISTORS

A Resistor is a passive two-terminal electrical component that implements

electrical resistance as a circuit element. The current through a resistor is in

direct proportion to the voltage across the resistor's terminals. Thus, the ratio of

the voltage applied across a resistor's terminals to the intensity of current

through the circuit is called Resistance. This relation is represented by Ohm's

Law:

Types Of Resistors


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RESISTOR: Fixed Value. VARIABLE RESISTOR:

o Rheostat Two Terminal Variable Resistors (Often For HighPower).

o Potentiometer Three Terminal Variable Resistor (VariableVoltage Divider).

o Trim potSmall Potentiometer, Usually for Internal Adjustments. HEATER: Heating Element. RESISTANCE WIRE, NICHROME WIRE: Wire of High-Resistance Material,

Often Used As Heating Element.

THERMISTOR: Temperature Varied Resistor. VARISTOR, VOLTAGE DEPENDENT RESISTOR, AND MOV: Passes Current

When Excessive Voltage Present.


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Table 1.1 Colours Coding Of Resistors.

3. CAPACITORSA Capacitor (originally known as condenser) is a passive two-terminal

electrical component used to store energy in an electric field. The forms of

practical capacitors vary widely, but all contain at least two electrical

conductors separated by a dielectric (insulator); for example, one common

construction consists of metal foils separated by a thin layer of insulating film.

Capacitors are widely used as parts of electrical circuits in many common

electrical devices. When there is a potential difference (voltage) across the

conductors, a static electric field develops across the dielectric, causing positive

charge to collect on one plate and negative charge on the other plate. Energy is

stored in the electrostatic field. An ideal capacitor is characterized by a single

constant value, capacitance, measured in farads. This is the ratio of the electric

charge on each conductor to the potential difference between them.

Types Of Capacitors:

POLYMER CAPACITORS:(OS-CON, OC-CON) capacitors use solid conductive polymer (or

polymerized organic semiconductor) as electrolyte and offer longer life and

lowerESRat higher cost than standard electrolytic capacitors.
http://en.wikipedia.org/wiki/Passivity_%28engineering%29http://en.wikipedia.org/wiki/Passivity_%28engineering%29http://en.wikipedia.org/wiki/Terminal_%28electronics%29http://en.wikipedia.org/wiki/Terminal_%28electronics%29http://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Dielectrichttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Potential_differencehttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Capacitancehttp://en.wikipedia.org/wiki/Faradhttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Equivalent_series_resistancehttp://en.wikipedia.org/wiki/Equivalent_series_resistancehttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Electric_chargehttp://en.wikipedia.org/wiki/Faradhttp://en.wikipedia.org/wiki/Capacitancehttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Potential_differencehttp://en.wikipedia.org/wiki/Electrical_circuithttp://en.wikipedia.org/wiki/Dielectrichttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Electric_fieldhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Electronic_componenthttp://en.wikipedia.org/wiki/Terminal_%28electronics%29http://en.wikipedia.org/wiki/Passivity_%28engineering%29


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VARIABLE CAPACITORS:With their plates open to the atmosphere were commonly used in radio tuning

circuits. Later designs use polymer foil dielectric between the moving and

stationary plates, with no significant air space between them.

ELECTROLYTIC CAPACITOR:The most important characteristic of electrolytic capacitor is that they

have polarity. They have a positive and negative electrode. This means that it is

very important which way round they are connected. If the capacitor is

subjected to voltage exceeding its working voltage or if it is connected with

incorrect polarity it may burst.

4. POWER SOURCES BATTERY: A Battery is a device that converts stored chemical energy

to electrical energy. Batteries are commonly used as energy sources in

many household and industrial applications.

FUEL: An Electrochemical Generator. POWER SUPPLY: Usually A Mains Hook-Up. PHOTO VOLTAIC DEVICE: Generates Electricity From Light.


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THERMO ELECTRIC GENERATOR: Generates Electricity FromTemperature Gradients.

ELECTRICAL GENERATOR: An Electrochemical Power Source.

4. SEMICONDUCTORS: DIODES:

A Diode is a two-terminal electronic component that conducts electric current

in only one direction. The term usually refers to a semiconductor diode. This is

a crystalline piece of semiconductor material connected to two electrical

terminals. A vacuum tube diode (now little used except in some high-power

technologies) is a vacuum tube with two electrodes: a plate and a cathode.

The most common function of a diode is to allow an electric current to pass in

one direction (called the diode's forward direction), while blocking current in

the opposite direction diodes can have more complicated behaviour than this

simple on-off action. This is due to their complex non-linear electrical

characteristics, which can be tailored by varying the construction of their P-N

junction. These are exploited in special purpose diodes that perform many

different functions.


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Today most diodes are made of silicon but other semiconductors such as

germanium are sometimes.

Types Of Diodes:1. ZENER DIODES:

Zener diodes (c & d) are designed to stabilize a voltage. The diodes are

marked as ZPD5.6V or ZPY15V having the operating voltages of 5.6V and

15V.

2. PHOTO DIODES:Photo diodes (e) are constructed in a way that they allow light to fall on

the P-N connection .when there is no light, a photo diode act as a regular diode.

It has high resistance in one direction, and low in other direction .when there is

light, both resistances are low. Photo diodes and LEDs are the main items in an

optocoupler.

3. TUNNEL DIODES:Tunnel diodes (f & g) diodes are commonly used in oscillator for very

high frequency.

4. SCHOTTKY DIODES:Schottky diodes (h) are used for high frequency circuits and for its low

voltage drop in the forward direction.

5. BREAKDOWN DIODES: Breakdown diodes (i) are actually Zener diodesused in various devices for protection and voltage regulation. It passes the

current only when voltage is rises above a pre defined value.


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6. VARICAP DIODE:Varicap diodes (j) are used instead of a variable capacitor in high

frequency circuits. When the voltage across it is changed, the capacitor between

cathode and anode is changed. This diode is commonly used in radio receivers,

transceivers and oscillators.

7. POWER DIODES:They are marked with a symbol engraved on the housing. If a diode is

housing in a metal package, the case is generally the cathode and anode is the

lead coming from the housing.

Table.1.2 a.Diodes; b. LED; c, d.Zener; e. Photo; f, g. Tunnel; h.Schottky;

i. Breakdown;j. Capacitive.TRANSISTORS:

A Transistor is a semiconductor device used to amplify and switch

electronic signals and power. It is composed of a semiconductor material with at

least three terminals for connection to an external circuit. A voltage or current

applied to one pair of the transistor's terminals changes the current flowing

through another pair of terminals. Because the controlled (output) power can be

higher than the controlling (input) power, a transistor can amplify a signal.


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Today, some transistors are packaged individually, but many more are found

embedded in integrated circuits.

The transistor is the fundamental building block of modern electronic

devices, and is ubiquitous in modern electronic systems. Following its

development in the early 1950s the transistor revolutionized the field of

electronics, and paved the way for smaller and cheaper radios, calculators, and

computers, among other things.

Types of Transistors:

1. BIPOLAR JUNCTION:Bipolar Transistors are so named because they conduct by using both

majority and minority carriers. The bipolar junction transistor (BJT), the first

type of transistor to be mass-produced, is a combination of two junction diodes,

and is formed of either a thin layer of p-type semiconductor sandwiched

between two n-type semiconductors (an n-p-n transistor), or a thin layer of n-

type semiconductor sandwiched between two p-type semiconductors (a p-n-p

transistor). This construction produces two p-n junctions: a baseemitter

junction and a basecollector junction, separated by a thin region of

semiconductor known as the base region (two junction diodes wired together

without sharing an intervening semiconducting region will not make a

transistor).


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2. FIELD EFFECT:The Field Effect Transistor (FET), sometimes called a unipolar transistor,

uses either electrons (in N-channel FET) or holes (in P-channel FET) for

conduction. The four terminals of the FET are named source, gate, drain, and

body (substrate). On most FETs, the body is connected to the source inside the

package, and this will be assumed for the following description.

INTEGRATED CIRCUITS (ICs):An Integrated Circuit or monolithic integrated circuit (also referred to

as IC, chip, or microchip) is an electronic circuit manufactured by lithography,

or the patterned diffusion of trace elements into the surface of a thin substrate of

semiconductor material. Additional materials are deposited and patterned to

form interconnections between semiconductor devices.

Integrated circuits are used in virtually all electronic equipment today and

have revolutionized the world of electronics. Computers, mobile phones, and

other digital home appliances are now inextricable parts of the structure of

modern societies, made possible by the low cost of production of integrated

circuits.


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LIGHT EMITTING DIODE (LED):A Light Emitting Diode (LED) is a semiconductor light source. LEDs

are used as indicator lamps in many devices and are increasingly used for other

lighting. Introduced as a practical electronic component in 1962, early LEDs

emitted low-intensity red light, but modern versions are available across the

visible, ultraviolet, and infrared wavelengths, with very high brightness.

When a light-emitting diode is forward-biased (switched on), electrons

are able to recombine with electron holes within the device, releasing energy in

the form of photons. This effect is called electroluminescence and the color of

the light (corresponding to the energy of the photon) is determined by the

energy gap of the semiconductor. LEDs are often small in area (less than 1

mm2), and integrated optical components may be used to shape its radiation

pattern. LEDs present many advantages over incandescent light sources

including lower energy consumption, longer lifetime, improved robustness,

smaller size, and faster switching. LEDs powerful enough for room lighting are

relatively expensive and require more precise current and heat management than

compact fluorescent lamp sources of comparable output.

Types Of LEDs:

1. MINIATURE:


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These are mostly Single Die LEDs used as indicators, and they come in

various sizes from 2 mm to 8 mm, through-hole and surface mount packages.

They usually do not use a separate heat sink. Typical ratings range from around

1 mA to above 20 mA.

The small size sets a natural upper boundary on power consumption due

to heat caused by the high current density and need for a heat sink.

2. MID RANGE:Medium Power LEDs are often through-hole-mounted and used when

an output of a few lumen is needed. They sometimes have the diode mounted to

four leads (two cathode leads, two anode leads) for better heat conduction and

carry an integrated lens. An example of this is the Super flux package, from

Philips Lumileds. These LEDs are most commonly used in light panels,

emergency lighting, and automotive tail-lights. Due to the larger amount of

metal in the LED, they are able to handle higher currents (around 100 mA). The

higher current allows for the higher light output required for tail-lights and

emergency lighting.

3. HIGH POWER:High Power LEDs (HPLED) can be driven at currents from hundreds of

mA to more than an ampere, compared with the tens of mA for other LEDs.


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Some can emit over a thousand lumens. Since overheating is destructive, the

HPLEDs must be mounted on a heat sink to allow for heat dissipation. If the

heat from a HPLED is not removed, the device will fail in seconds. One

HPLED can often replace an incandescent bulb in a flashlight, or be set in an

array to form a powerful LED lamp.

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basics of electronics.docx