electronic components.

ELECTRONIC COMPONENTS:

capacitors: capacitors is passive elements. it is a physical device which is capable of storing energy by virtue of a voltage exiting across it. the voltage applied across the capacitor sets up an electric field within it and the  energy is stored in the electric field. 

A capacitor is basically meant to store electrons( or electrical  energy), and release them whenever required. Capacitance is a measure of a capacitor's ability to store charge and is measured in farads(F).Farad,the unit of capacitance is very large,so microfarad (uF) or micro-microfarad(uuF) is usually used 1 uF and 1uuF,also called the picofarad(pF).

A capacitor offers low impedance to ac but very high impedance to dc.so capacitors are used to couple alternating voltage from one circuit to another circuit and at the same time to block dc voltage from reaching the next circuit.It is also  employed as a bypass capacitor where it passes the ac through it without letting the dc to go through the circuit across which it is connected.A  capacitor forms a tuned circuit in series or in parallel with an inductor.

capacitors are used for waveform generation , filtering , blocking and differentiator, In combination with inductors,they make possible sharp filter for separating desired signals from background.

different type of capacitors

capacitor is basically meant to store electrical energy.

inductors:

 an insulator is physical device which is capable of storing energy by virtue of a current flowing through it.An inductor  has  been defined as a physical device which is capable of storing energy by virtue  of a current flowing through it. An inductor is a circuit components which opposes the change of current flowing through it varies in magnitude and/or direction.

In case of an inductor current does not change instantaneously.It offers high impedance to ac but very low impedance to dc i.e., it blocks ac signal but passes dc signal.

A piece of wire, or a conductor of any type,has inductance i.e., a property of opposing  the change of current through it.By coiling the wire the inductance is increased as the square of the number of turns. the inductance is represented by a English capital latter L and measured in henrys. 

      specially made components consisting of coiled copper wire called the inductors. Inductors are of two types viz.,air-core(wound on non-ferrous)and iron-core(wound on ferrite cores). Inductors range in value from the tiny (few turn air-core coils of 0.1 uH used in high frequency systems) to iron-core choke coils 50H or more for low frequency applications.
The inductors can be classified into filter chokes, audio-frequency chokes and radio-frequency chokes.
Filter chokes has many turns of fine wire wound on an iron core made of laminated sheets of E- and I-shapes and is used in smoothing the pulsating current produced by rectifying ac into dc. Generally power supplier use filter chokes having inductance ranging from about 1H to 50H,capable of carrying current up to 500 mA.

Resistors: resistors are employed in amplifiers as loads for active devices,in bias networks,and feedback elements.

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LED: LED is stand for a light emitting diodes.LED is work on forword wise and there are two terminal anode and cathode(+ve and -ve).all opto electronic devices is the so called LED(light-emitting diode),which  emits a fairly narrow bandwidth of visible (usually red,orange,yellow or green) or invisible(infrared) light when its internal diode junction is stimulated bt a forward electric current/voltage (power).LEDs have typical power-to-light energy conversion efficiencies some 10 to 50  times greater  than of a simple tungsten lamp and have very fast response times,(approximately 0.1us compared with tens or hundred of milliseconds dor a tungster lamp),and are thus widely employed as visual indicators and as moving light displays.

the operation of light-emitting diode(LED) is based on the phenomenon of electroluminance,which is the emission of light from a semiconductor under the influence of an electrical field. the recombination of charge carriers take place in a forward P-N junction as the electrons cross from the N- region and recombine with holes exiting in P-region. free electrons are in the conduction band of energy levels,while holes are in the valence energy band. therefore, the electrons are at high energy levels than the holes. for the electrons to recombination with the holes,they must give some of their energy. typically,these electrons give up  energy in the form of heat and light.

 In silicon and germanium diodes,most of the electrons give up their energy in the form of heat. however, with GaAsP,and GaP semiconductor, the electrons give up their energy by emitting photons. If the semiconductor is transluscent, the light will be emitted and the junction becomes a source of light,i.e., a light-emitting diode (LED). LEDs emit no light when reverse biased. in fact,operating LEDs in reverse bias mode will quickly destroy them.
(+ve)→→→←←(-ve)

picture of led and there use

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  • picture of some electronic components

Advantage of LEDs:

• LEDs are miniature in size and can be stacked together  to form numeric and alphanumeric displays in high density matrix.
• Smooth control of light intensity from an LED because  light output from an LED is a function of current flowing through it.
• LEDs are economical and have a high degree of reliability because they are manufactured with the same type of technology as is used for transistors and ICs.
• LEDs can be operated over a wide temperature range (0-70 degree C).
• The switching time (both on and off) is less than 1 ns. so they are very suitable where dynamic operation of large number of arrays is involved.
• LEDs are available in different colours like red,yellow , green, and amber.
• They need moderate power.They are used where low dc power is available.
• they occupy small area.
•  LEDs that emit visible light are widely used in instrument display panel indicator,digital watches ,calculators,multimeters,  intercom,telephone switchboards,etc. LEDs  that emit invisible infrared light find application in remote control schemes,object detectors,burglar alarm systems;and other areas requiring invisible radiation.