ELEKTRONIKBidang elektronik boleh dibahagikan kepada TIGA iaitu :

PERALATAN LITAR KOMPONEN

PERALATANPeralatan elektronik yang menggunakan komponen elektronik ialah seperti :

Jam TV Radio Komputer Kamera

LITARLitar elektronik merupakan sambungan pelbagai komponen elektronik bagi fungsi-fungsi tertentu seperti : Sambungan SIRI Sambungan SELARI Sambungan SIRI-SELARI

KOMPONENSemua litar elektronik sama ada litar ringkas atau litar kompleks dibina menggunakan komponen-komponen elektronik seperti : Perintang Diod Kapasitor Transistor IC

KOMPONEN ELEKTRONIKKomponen elektronik tergolong kepada kepada dua kategori :KOMPONEN ELEKTRONIKAKTIF PASIF

AKTIFKomponen elektronik yang bertindakbalas apabila dilalukan AE padanya, seterusnya ia menukarkan dirinya dari satu bentuk tenaga kepada satu bentuk tenaga yang lain.ATAUKomponen yang keadaan operasi dalamannya diubah oleh kuasa dari luar ketika litar sedang dikendalikan.CONTOHDIODTRANSISTORLITAR BERSEPADU

PASIFKomponen elektronik yang tidak bertindakbalas apabila dilalukan AE melaluinya, Ia menerima pengaruh tetapi tidak mempengaruhi atau tidak membuat faktor gandaan di dalam isyarat elektrik.ATAUKomponen yang tidak mengalami perubahan dalaman apabila dikendalikan dalam litar.PERINTANGPEMUATPEARUHCONTOH

Electronic ComponentsActivePassive Resistor (click here) Capacitor (click here) Inductor (click here)Integrated circuit (click here) Diode (click here) Transistor (click here)Transformer (click here) Semiconductor (click here)

ResistorUnitResistance, R is the property of a material to resist the flow of Electrons.Resistance is measured in ohms, the symbol for ohm is an omega ().

Function Resistors restrict the flow of electric current.

Symbol of Resistoror

Carbon resistor(click here)Types of Resistor Thin film resistor(click here)Wire-wound resistor(click here)TYPES

Carbon resistor Made from carbon or graphite mixed with insulator powder as a binder. The most common resistor in the market.The common resistance value is from 1ohm to 20 Mega ohm.

Wire-wound resistor Made from nickel chromium alloy wire that is wound onto ceramic rod.Used in high current circuit which emphasizes the accuracy of resistance value.Range of resistance is from a fraction of an ohm to several thousands ohms.

Thin film resistor Thin Metal Film ResistorThin Carbon Film ResistorSmall in size.

Tolerance value can be as low as 0.1%.

Range of resistance value is from 10 ohm to 2.5 Mega ohm.Types

Resistance value

The value is colour-coded.

The resistance value is written in ink on the body of the resistor.There are two ways to determine the value of a resistor:

Colour codes for a resistor

Examples of resistor value

The first band gives the first digit. The second band gives the second digit. The third band indicates the number of zeros. The fourth band is used to shows the tolerance (precision) of the resistor.This resistor has yellow (4), violet (7), red(2 zeros) and gold bands. So its value is 4700 5% = 4.7k 5%How to determine the value

Thin film resistor Thin Metal Film ResistorThin Carbon Film ResistorSmall in size.

Tolerance value can be as low as 0.1%.

Range of resistance value is from 10 ohm to 2.5 Mega ohm.Types

Resistance value

The value is colour-coded.

The resistance value is written in ink on the body of the resistor.There are two ways to determine the value of a resistor:

Colour codes for a resistor

Examples of resistor value

The first band gives the first digit. The second band gives the second digit. The third band indicates the number of zeros. The fourth band is used to shows the tolerance (precision) of the resistor.This resistor has yellow (4), violet (7), red(2 zeros) and gold bands. So its value is 4700 5% = 4.7k 5%How to determine the value

What is power rating When current flows through a resistance, electrical energy is converted into heat.The resistor must be able to withstand the heating effect.

Variable ResistorAllow the resistance value to be changed.

Variable resistors consist of a resistance.

Element with connections at both ends and a sleeve which moves along the resistance element as you turn the spindle.Internal view of a variable resistor

Types of variable resistorRheostat(click here)Potentiometer(click here)TYPES

RheostatRheostats are often used to vary current.

Two terminals are used. Symbol:or

Example of usageDimmer

PotentiometerPotentiometer used to vary voltage.

Variable resistors used as potentiometers have all three terminals connected. Symbol:or

Example of usageSpeed control

Networks of Resistors Two main ways to connect resistors in a circuit.(a) Series(b) Parallel

CapacitorFunction A capacitor is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed.

Unit Capacitance, C is the ability to store electric charges. Capacitance is measured in units called farad (F).

1 farad capacitor is actually a very big capacitor indeed so we use microfarads (F) where 1 F = 1 10-6 F. Smaller capacitors are measured in nanofarads (nF), 10-9 F, or picofarads (pF), 1 10-12 F.

Inside the capacitor, the terminals connect to two metal plates separated by a dielectric.

The dielectric can be air, paper, plastic or anything else that does not conduct electricity and keeps the plates from touching each other DielectricMetal platesStructure of A Capacitor

Categories of CapacitorNon-electrolytic(click here)Electrolytic(click here)CATEGORY

Non-electrolytic Capacitor Types of non electrolytic capacitor are mica, paper, ceramic and air.Does not has positive and negative terminals.Ceramic capacitors that are suitable for use in high frequency applications. They have a low capacitance, but are stable at high frequency. They can also work in hot environments.Symbol:

Electrolytic CapacitorSymbol:Structure of an electrolytic capacitorIt has specific positive and negative terminals.It must be connected correctly of it may explode and damage other components.Tantalum bead capacitors, which use an electrolytic principle. They are very small in size, but can have values of up to 10 F.

The Variable CapacitorThe variable resistor consists of several plates in two stacks.One stack is fixed while the other can be moved.The effect of this is that the capacitance can be altered.It is used in tuning a radio.

Symbol:

How a capacitor chargeWhen the power supply is connected to the capacitor electron will move to plate B.Electrons from plate A will be attracted by the positive terminal of the power supply.Plate B will have more electrons while plate A will have less electrons.This will cause a potential difference between the two plates.Electrons cannot flow from plate B to plate due to the presence of the dielectric.When the voltage between these two plates is equal to the voltage of the power supply, the flow of electrons will stop (capacitor is fully charged).The charge will remain even though the power supply is disconnected from the capacitor.

How a capacitor dischargeWhen a connection is made between the terminals of the capacitor, it discharged.Electrons on plate B will be drawn to plate A, which lacks electrons.The bulb which is connected across the capacitor will light up as the current passes through it.The capacitor is fully discharged when the number of electrons on plate B equals the number of electrons on plate A (the voltage across the terminals equals zero).

Examples of usageAs a filterA coupler(to remove DC component from the input and output that might interfere with the DC operating point of the amplifier)A by-pass(effect on the amplifier gain)

InductorFunctionTo produce an induced voltage when the current that flows through it changes.

UnitInductance, L is the ability of a conductor to produced an induced voltage.The unit of inductance is henry (H).

Symbol of InductorInductorVariable inductororor

What does the inductance depends to?The inductance depends on the following:

The number of windings or turns on the coil. More turns, more voltage is induced. The diameter of the coil. With an equal number of turns, inductance increases directly with the diameter. The type of core. Inductance of a coil increases directly as the permeability of the core material increases. The length of the coil. With the number of turns, the more length of a coil reduced the inductance.

Types of coreTypesAirIronMica

Magnetic field is produced through & around the coil when current is applied to the wire.Changes in the current magnitude, will effect the magnetic field. If the current increases, the magnetic field will expand.If the current decreases, the magnetic field will contract.The expansion and contraction of the magnetic field will cut through the coil to produce an induced voltage.When the current reaches its maximum and minimum level, there is no relative movement between the coil and the magnetic field, so the induced voltage is not generated. Inductor operation

Examples of usageAn oscillator circuit

A filtering circuit

Transformer The voltage we get depends on the number of turns on windings of the transformer.FunctionTransformers convert AC electricity from one voltage to another with little loss of power. Step-up transformers increase voltage

Step-down transformers reduce voltage

Symbol of Transformeror

The input coil is called the primary and the output coil is called the secondary. The coils on a transformer Structure of a transformerThere is no electrical connection between the two coils, instead they are linked by an alternating magnetic field created in the soft-iron core.The two lines in the middle of the circuit symbol represent the core. The ratio of the number of turns on each coil, called the turns ratio, determines the ratio of the voltages.

What is mutual inductance?A simple transformer consists of two electrical conductors called the primary winding and the secondary winding. Magnetic flux is produced by the primary winding, and contained by the high permeability core, links the secondary winding. The mutual inductance between the two windings results in an induced voltage on the secondary side, whose magnitude is determined by the ratio of turns between the two windings.

Power transformer.Step-up The secondary has more turns than the primary.

Step-down The secondary has fewer turns than the primary.

Audio transformer. Radio frequency(RF) transformer.

Types of transformer

SemiconductorSilicon and germanium are examples for semiconductor materials.Examples of semiconductor components are diode, transistor, integrated circuit and components of thyristor which are made from doped semiconductor.Silicon atom bonding

What is doping?Semiconductors contain two types of mobile charge carriers, holes and electrons. The holes are positively charged, the electrons negatively charged. The process of adding impurities is called doping.It contains mobile charges which are mainly holes.It contains mobile charges which are primarily electrons.

Has excess holes.

Has excess electrons.Indium is the dopant. Indium has only three electron valences.

Arsenic is added to the silicon in small quantities. Arsenic has 5 electron valences.P-type DopingN-type DopingHas negative polarity characteristics.

Has positive polarity characteristics.

DiodeDiodes are made from semi-conductor materials like silicon and germanium. SymbolDiode structure

Junction between the layers, forming a depletion zone. We create a pn-junction by joining together two pieces of semiconductor, one doped n-type, the other p-type Inside a diode

How diode works in forward-biasedThe diode is connected to a battery. Anode to the positive terminal and cathode to the negative terminal. Electrons and holes start moving and the depletion zone disappears.

In circuit A the diode is forward-biased so the current flows and the motor will turn. the current flows Diode in a forward-biased circuit

How diode works in reverse-biasedAnode is connected to the negative terminal and cathode is connected to the positive terminal of the battery. Free electrons collect on one end of the diode and holes collect on the other. The depletion zone gets bigger.

In circuit B the diode is reverse-biased, the current will not flow and the motor will not turn. the current will not flow Diode in a reverse-biased circuit

Diodes have a low resistance when they are forward biased, and a very high resistance when they are reverse-biased.

This means that current can flow one way only.

Diodes are one-way electrical valves that allow current to flow in one direction only.

Function of A Diode

4 main kinds of diode

The zener diode is designed to be used in a reverse biased configuration. The light emitting diode (LED) has replaced indicator lamps in many devices.

TransistorsTwo types of standard transistors,Transistors have three leads.The leads are labelled base (B), collector (C) and emitter (E).

The structure & usage of different types of transistor

Structure of transistorsArrow indicates the direction of conventional flow of currentJunctionJunctionTransistors have two junctions

Various types of transistors

Transistor as a switchThe transistor acts exactly like a switch but the input is electronic and not mechanical

Transistor as an amplifier The transistor functions by controlling the current flow (electron movement). Changes of current value in the transistor can be used for amplification.

Integrated Circuit (IC)Consists of transistors, resistors and capacitors integrated in a single package.Categorised according to their fabrication techniques.

Integrated Circuit (IC)Consists of transistors, resistors and capacitors integrated in a single package.Categorised according to their fabrication techniques.All components are part of a single wafer of p-type material (or n-type material).

Integrated Circuit (IC)Consists of transistors, resistors and capacitors integrated in a single package.Categorised according to their fabrication techniques.The substrate is ceramics. All components are deposited on this insulating material.

Integrated Circuit (IC)Consists of transistors, resistors and capacitors integrated in a single package.Categorised according to their fabrication techniques.The resistor and capacitor are made on the base material, while the transistor and diode are discrete.

Integrated Circuit (IC)Consists of transistors, resistors and capacitors integrated in a single package.Categorised according to their fabrication techniques.A combination of the monolithic and thin film types on a ceramic base. A discrete transistor may be incorporated if high power is used.

Types of ICLinear type Handles analogue signals.

Digital type Handles digital signals.

Preparing The Integrated Circuit Design

Manufacturing Integrated Circuit

Packaging the chip

DC Power Supply

Inside The Power Supply

Major Components In The DC Power Supply

What Happen At The TransformerInputDecreases voltage to the desired value.

Transform Alternating Current To Direct Current(Diode As A Rectifier)Output: half-wave varying DC (using only half the AC wave) The diode conducts on the positive half of each cycle and passes the voltage to the loadThe diode blocks the current on the negative half of the cycleHalf-Wave Rectifier

Full-Wave Rectifier

Bridge Rectifier

Smoothing(Capacitor as a filter)

Stabilising(Zener diode as a regulator)

Audio AmplifierAmplifies signals (AC) at a frequency range between 20 to 20000 Hz.Divided into two parts:Voltage amplifier to double the voltage valuePower amplifier to provide higher power to the load (loudspeaker)

Simple Voltage Amplifier(Using transistor)

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