day2 basic electronics

7/30/2019 Day2 Basic Electronics

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Resistor

A resistoris a two-terminal passiveelectronic component. It is an electricalcomponent that limits or regulates the flow

of electrical current in an electronic circuit.Resistors can also be used to provide aspecific voltage for an active device suchas a transistor.

Symbol:


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Conti.

S.I unit is ohm

Symbol of ohm () Notation for resistance

O- for ohm

K- for kilo ohmM- for mega ohm


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Types of resistor

Fixed type resistor

Variable type resistor


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Combinat ion of res is tor

series combination

parallel combination


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Conti

Series combination


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Conti.

Parallel combination


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CONTI.

In series the current remains same

In parallel the voltage remains same


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Ohms law

Ohm's law states that the current through

a conductor between two points is directly

proportional to the potential difference

across the two points, and inverselyproportional to the resistance between

them.

The mathematical equation that describesthis relationship is:


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Color coding table


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Why we use resistor?

Limiting of current

Limiting of voltage

Power dissipation


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Capacitor


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A capacitor is a device for storing electric

charge

A capacitor is a passive electronic component

consisting of a pair of conductors separated by

a dielectric (insulator).


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CAPACITANCE

This is a measure of a capacitor's ability to store charge.

A large capacitance means that more charge can be stored.

Capacitance can be measured using formula:q = C V

where

C = capacitance,

q= charge,

V = potential difference.

Unit of Capacitance is Farads(F).


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Combination of capacitors

Series combination



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Series combination

When capacitors are connected in series,

the capacitance decreases.

In Series, total capacitance is given by the

formula:

1/Ct= 1/C1+1/C2+


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When capacitors are connected in parallel,

the capacitance increases.

In Parallel, total capacitance is given by

the formula:

Ct= C1+ C2+Cn


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Types of capacitor

Polarized capacitor

Non polarized capacitor


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Non Polarized capacitor

The capacitor which do not have a polarity


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Polarised capacitor

The capacitor which have a polarity


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How to Read Ceramic Capacitor


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Features

Capacitor offers low impedance to AC.

It offers high impedance to DC.

Reactance of capacitor is given by:

Xc =1/2 fc

where =22/7


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Applications

Blocking DC Voltage

Adjusting Frequency

Use to generate a time delay application

Smoothing of dc voltage.


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Diodes


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Diode

Diode is an electronic component which

permits the flow of current in one direction

only.

Today diodes are made up of

semiconductor material, therefore they are

often called semiconductor diodes or

crystal diodes.


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Why we use it?

Diodes are used for rectification.

Diodes are used in electrical meters for

there protection.

Diodes are used in wave shaping circuits.

Diodes (LED) are used in display.


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Material

Diodes are semiconductor devices.

Silicon(Si) or germanium(Ge) are used.


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Types

PN junction diode

Zener Diode

Light Emitting Diodes (LED)

Photo Diodes


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PN Junction Diode

This diode is made by p-type & n-type

material.

This PN junction diode works in forward

bias i.e. anode is connected to positive

terminal & cathode is connected to

negative terminal.


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Symbol


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How can we recognize?

There is a silver band on the one side of

diode which is cathode (negative) terminal

of the diode & the other side is anode(positive) terminal.


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Zener Diode

Zener Diode works in reverse bias.

Symbol of zener diode:


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How can we recognize zener a

diode?

There is black band which is negative

terminal & other one is positive terminal.


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Light Emitting Diode (LED)

Light Emitting Diode (LED) operates in

forward bias.

It emits light when connected in circuit.

Symbol of LED:


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How can we recognize LED?

The shorter lead of the LED is negative

terminal & longer one is positive, also on

the negative terminal there is a flat spot

when we see from the top.


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Photo Diode

Often known as Photo detector.

Photo Diode operates in reverse bias.

Light falls on the PN junction of the photo diode whichcreates electron-hole pair in the depletion layer whichcauses flow of current.

Current depends upon the light intensity

When light incident on the photodiode then current flowsin the circuit.


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Physical view of Photo diode:


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Working of Photodiode

Photodiode


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LDR(Light Dependent Resistor)

A light dependent resistor is a semiconductor

electrical device that has a very high

resistance to the flow of electrical current in t

absence of light.

When light strikes the device, it lowers its

resistance, allowing electrical current to flow

through it and on to other devices or electricalcircuits.


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TRANSISTOR


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TRANSISTOR

A transistoris a semiconductor device used

to amplify and switch electronic signals. It is

made of a solid piece

of semiconductor material, with at least threeterminals for connection to an external circuit.

Device with three terminals where one

terminal can be use to control the flow ofcurrent through the other two terminals.


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Conti.

The three terminals are Emitter, Base and

Collector


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Types of transistor

Junction transistor

Field effect transistor


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Junction transistor

Transistor are of two types:

1-> n-p-n

A straight switch

2-> p-n-p

A inverted switch


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n-p-n as a switch

When base of n-p-n is connected with

logic high voltage then it short circuit

emitter and collector (SWITCH ON).

When base of n-p-n is connected with

logic low voltage then it open circuit both

emitter and collector (SWITCH OFF).


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Circuit diagram to show a switching

RB

M

VCC

Logic 0

Logic 1

or

GND

Logic transistor Motor

0 off stop1 on run


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p-n-p as an inverted switch

When base of p-n-p is connected with

logic high voltage then it open circuit

emitter and collector (SWITCH OFF).

When base of p-n-p is connected with

logic low voltage then it short circuit both

emitter and collector (SWITCH ON).


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Practically used

As a switch

As an amplifier

For realizing logic gates


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ICS


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L293D

555

LM358

IC 7805(voltage controlled)


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L293D IC

VccEN1

EN212V


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Truth table


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Conti.

L293D is a dual H-Bridge motor driver. So with one IC we can interface two DC motors

which can be controlled in both clockwise andcounter clockwise direction

If you have motor with fix direction of motionthen you can make use of all the four I/Os toconnect up to four DC motors.

L293D has output current of 600mA.

Moreover for protection of circuit from back EMFoutput diodes are included within the IC.


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Interface motor with IC L293D

EN1

EN212V

VCC


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555 IC


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The 555 Timer IC is an integrated circuit (chip)

used in a timer application, pulse generation

and oscillator applications.

It works only on falling edge of the incoming

signal


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Operating modes:

It has three operating modes:

1) monostable

2) Bistable

3) Astable


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Monostable mode

In this mode, the IC has only one stable state

voltag

e

triggering pulse

output

time

voltag

e


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Bistable mode

In this mode, the IC has two stable state


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Astable mode

In this mode, the IC not having a single stable

state


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LM358

The LM358 IC consists of two independent

operational amplifiers which were designed

specifically to operate from a single power

supply over a wide range of voltages. It have two op-amp

Single power supply


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LM358 IC


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Internal circuit


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Features

It have two op-amp

Single power supply

Supply range 3v-32v

Eliminate need of dual supply


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IC 7805

It is a voltage regulator integrated circuit.

It designed to automatically maintain a

constant voltage level

It works on a negative feedback


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IC 7805


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Features

Output current range up to 1A

Output voltage 5V

Input voltage range up to 12V

Short circuit protection


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Thank you

day2 basic electronics

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