Details of project.

1. A PROJECT REPORT ON
GSM BASED WIRELESS ENERY METER
Submitted in
Partial fulfillment of the requirements for the award of the degree
BACHELOR OF TECHNOLOGY
IN
ELECTRICAL & ELECTRONICS ENGINEERING
SUBMITTED TO: SUBMITTED BY:
ER. SONAM JAIN 1.SANJEET KUMAR (1308143)
(PROJECT INCHARGE) 2.UTTAM KR OJHA (1308278)
3. ZUBAIR HUSSAIN (1308282)
(SESSION: 2013-2017)
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING
CT INSTITUTE OF TECHNOLOGY
(APPROVED BY AICTE, NEW DELHI AND AFFILIATED TO I.K GUJRAL PUNJAB
TECHNICAL UNIVERSITY, JALANDHAR)

2. CERTIFICATE
This is to certify that the project work entitled, “GSM BASED WIRELESS ENERGY
METER”, is the work done by SANJEET KUMAR, UTTAM KUMAR OJHA, ZUBAIR
HUSSAIN, submitted in partial fulfillment for the award of BACHELOR OF ENGINEERING
(B.Tech) in ELECTRICAL & ELECTRONICS ENGINEERING. from CT INSTITUTE OF
TECHNOLOGY. Affiliated to I.K.GUJRAL PUNJAB TECHNICAL UNIVERSITY.
MR. S.S. MATHARU ER. SONAM JAIN
(Head of the department, EE) (Project Incharge)

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ACKNOWLEDGEMENT
The satisfaction and euphoria that accompany the successful completion of any
task would be incomplete without the mentioning of the people whose constant
guidance and encouragement made it possible. We take pleasure in presenting
before you, our project, which is result of studied blend of both research and
knowledge.
We express our earnest gratitude to our internal guide, Research Assistant,
ER. AMAN CHAUDHARY, Department of EE/EEE, our project guide, for his
constant support, encouragement and guidance. We are grateful for his cooperation
and his valuable suggestions.
1

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DECLARATION
We, the undersigned, declare that the project entitled, “GSM BASED WIRELESS
ENERGY METER”, being submitted in partial fulfillment for the award of
Bachelor of Technology Degree in Electrical & Electronics Engineering,
affiliated to I.K.GUJARAL PUNJAB TECHNICAL UNIVERSITY, is the work
carried out by us.
(SANJEET KUMAR)
(UTTAM KR OJHA)
(ZUBAIR HUSSAIN)

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CONTENTS PAGE NO.
ACKNOWLEDGEMENT 1
1. Introduction 3-5
2. Block Diagram of Project 5
3. Hardware Requirements 6-40
3.1 Digital Energy Meter 6-14
3.2 GSM Modem 14-18
3.3 Nano Arduino 18-21
3.4 Transformer 21-23
3.5 Voltage Regulator (7805) 23-25
3.6 Bridge Rectifier 25-34
3.7 LCD (16*2) Display 34
3.8 Resistor 34-38
3.9 Capacitor 38-40
 Results 40
 References 42

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LIST OF FIGURES PAGE NO.
Fig 1:- Prepaid Energy Meter using GSM and Arduino 3
Fig 2 :- Block diagram of GSM based wireless energy meter 5
Fig 3: - Digital energy meter 6
Fig 4: - Electromechanical meter 9
Fig 5: - Solid state electricity meter used in a home in the Netherlands 10
Fig 6: - Meter and Tele switcher 11
Fig 7: -Prepayment meter 12
Fig 8: - prepayment key 12
Fig 9: -Structure of a GSM modem 15
Fig 10:- GSM Modem 15
Fig 11:- Base station subsystem 16
Fig 12: - Nano arduino 18
Fig 13:- Typical transformer 21
Fig14: - Ideal transformer as a circuit element 22
Fig 15: - Voltage regulator 23
Fig 16: -Block diagram of voltage regulator 24
Fig 17: -Full Wave Bridge Rectifier Circuit Diagram with Input and Output Wave Forms 26
Fig 18: -Flow of current in Bridge Rectifier 27
Fig 19: -Path of current in 2nd Half Cycle 28
Fig 20: -Full Wave Rectifier with Capacitor Filter 31
Fig 21:- Power supply component 33
Fig 22: - Liquid crystal oscillator 34
Fig 23: - Registers 35
Fig 24: - Capacitors 38

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1. INTRODUCTION
In present time Electricity is the necessary thing in the world for human life. Today every home,
offices, companies, industries have electricity connection. So here this project is building only
for interfacing electricity energy meter with microcontrollers. Here, Arduino is used for
interfacing and the main aim of this project is to know, how much unit is obtained and the total
amount of rupees has to be paid. This will help both the inspector and the owner of the place
where the meter is placed; we can simply view the unit and the total money that we have to paid
and also send to our cell phone using GSM module.
Fig 1:- Prepaid Energy Meter using GSM and Arduino
Here meter is interfaced with microcontroller through the pulse that is always blinked on the
meter. Further that pulse is calculated as per its blinking period, using this principle we
calculated it for one unit and accordingly what charge will be for a unit. After 0.3125 watt
energy uses Meter LED (calibrate) blinks. Means if we use 100 watt bulb for a minute then the
pulse will blink 5.2 times in a minute. And this can be calculates using given formula.
Pulse= (Pulse rate of Meter* watt * 60) / (1000 * 3600)
If pulse rate of meter is 3200 imp and watt used is 100 then we have
Pulse = (3200 * 100 * 60) / (1000 * 3600)

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Pulse = 5.333333333 per minute
If 5.3333333333 pulses occurred in a minute then
In one hour pulses will occur..
Pulse = 5.3333333333* 60
Pulse = ~320
~320 Pulses will occur in a hour
So, in one hour 100 watt bulb consumed 100 watt electricity and almost 320 pulses blinks.
Now we can calculates one pulse electricity consumed in watt
One pulse (watt) = 100320
One Pulse (watt) = 0.3125
Means 0.3125 watts electricity consumed a single pulse.
Now Units
Unit = (one pulse energy (electricity) )* pulses / 1000
If
One pulse = 0.3125 watt
Pulses in 10 hours = 3200
Then Unit will be
Unit = (0.3125 * 3200)/1000
Unit = 1
Means, One unit in 10 hours for a 100 watt bulb.
Now Suppose one unit rate is 7 rupee then
For a single pulse cost will be
Single pulse cost = (7 * one pulse energy consumed) / 1000
Single pulse cost = (7 * 0.3125) / 1000
Single pulse cost = 0.0021875 Rupee

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2. BLOCK DIAGRAM
Fig 2 :- Block diagram of GSM based wireless energy meter

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3. HARDWARE REQUREMENT
3.1 DIGITAL ENERGY METER
An electricity meter, electric meter, electrical meter, or energy meter is a device that
measures the amount of electric energy consumed by a residence, a business, or an electrically
powered device. Electric utilities use electric meters installed at customers' premises to measure
electric energy delivered to their customers for billing purposes. They are typically calibrated in
billing units, the most common one being the kilowatt hour [kWh]. They are usually read once
each billing period. When energy savings during certain periods are desired, some meters may
measure demand, the maximum use of power in some interval. "Time of day" metering allows
electric rates to be changed during a day, to record usage during peak high-cost periods and off-
peak, lower-cost, periods. Also, in some areas meters have relays for demand response load
shedding during peak load periods.
Fig 3: - Digital energy meter

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Unit of measurement
The most common unit of measurement on the electricity meter is the kilowatt hour [kWh],
which is equal to the amount of energy used by a load of one kilowatt over a period of one hour,
or 3,600,000 joules. Some electricity companies use the SI megajoule instead.
Demand is normally measured in watts, but averaged over a period, most often a quarter- or half-
hour.
Reactive power is measured in "thousands of volt-ampere reactive-hours", (kvarh). By
convention, a "lagging" or inductive load, such as a motor, will have positive reactive power. A
"leading", or capacitive load, will have negative reactive power.[13]
Volt-amperes measures all power passed through a distribution network, including reactive and
actual. This is equal to the product of root-mean-square volts and amperes.
Distortion of the electric current by loads is measured in several ways. Power factor is the ratio
of resistive (or real) power to volt-amperes. A capacitive load has a leading power factor, and an
inductive load has a lagging power factor. A purely resistive load (such as a filament lamp,
heater or kettle) exhibits a power factor of 1. Current harmonics are a measure of distortion of
the wave form. For example, electronic loads such as computer power supplies draw their current
at the voltage peak to fill their internal storage elements. This can lead to a significant voltage
drop near the supply voltage peak which shows as a flattening of the voltage waveform. This
flattening causes odd harmonics which are not permissible if they exceed specific limits, as they
are not only wasteful, but may interfere with the operation of other equipment. Harmonic
emissions are mandated by law in EU and other countries to fall within specified limits.
Other units of measurement
In addition to metering based on the amount of energy used, other types of metering are
available.
Meters which measured the amount of charge (coulombs) used, known as ampere-hour meters,
were used in the early days of electrification. These were dependent upon the supply voltage
remaining constant for accurate measurement of energy usage, which was not a likely
circumstance with most supplies. The most common application was in relation to special-
purpose meters to monitor charge / discharge status of large batteries.
Some meters measured only the length of time for which charge flowed, with no measurement of
the magnitude of voltage or current being made. These are only suited for constant-load
applications and are rarely used today.

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Types of meters
Electricity meters operate by continuously measuring the instantaneous voltage (volts)
and current (amperes) to give energy used (in joules, kilowatt-hours etc.). Meters for smaller
services (such as small residential customers) can be connected directly in-line between source
and customer. For larger loads, more than about 200 ampere of load, current transformers are
used, so that the meter can be located other than in line with the service conductors. The meters
fall into two basic categories, electromechanical and electronic.
Electromechanical meters.
The most common type of electricity meter is the electromechanical induction watt-hour meter.
The electromechanical induction meter operates by counting the revolutions of a non-magnetic,
but electrically conductive, metal disc which is made to rotate at a speed proportional to the
power passing through the meter. The number of revolutions is thus proportional to the energy
usage. The voltage coil consumes a small and relatively constant amount of power, typically
around 2 watts which is not registered on the meter. The current coil similarly consumes a small
amount of power in proportion to the square of the current flowing through it, typically up to a
couple of watts at full load, which is registered on the meter. The disc is acted upon by two sets
of coils, which form, in effect, a two phase induction motor. One coil is connected in such a way
that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic
flux in proportion to the current. The field of the voltage coil is delayed by 90 degrees, due to the
coil's inductive nature, and calibrated using a lag coil.[16] This produces eddy currents in the disc
and the effect is such that a force is exerted on the disc in proportion to the product of the
instantaneous current, voltage and phase angle (power factor) between them. A permanent
magnet acts as an eddy current brake, exerting an opposing force proportional to the speed of
rotation of the disc. The equilibrium between these two opposing forces results in the disc
rotating at a speed proportional to the power or rate of energy usage. The disc drives a register
mechanism which counts revolutions, much like the odometer in a car, in order to render a
measurement of the total energy used. The type of meter described above is used on a single-
phase AC supply. Different phase configurations use additional voltage and current coils.
Fig 4: - Electromechanical meter
The amount of energy represented by one revolution of the disc is denoted by the symbol Kh
which is given in units of watt-hours per revolution. The value 7.2 is commonly seen. Using the

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value of Kh one can determine their power consumption at any given time by timing the disc
with a stopwatch. .
Where:
t = time in seconds taken by the disc to complete one revolution,
P = power in watts.
For example, if Kh = 7.2 as above, and one revolution took place in 14.4 seconds, the power
is 1800 watts. This method can be used to determine the power consumption of household
devices by switching them on one by one.
Electronic meters
Electronic meters display the energy used on an LCD or LED display, and some can also
transmit readings to remote places. In addition to measuring energy used, electronic meters can
also record other parameters of the load and supply such as instantaneous and maximum rate of
usage demands, voltages, power factor and reactive power used etc. They can also support time-
of-day billing, for example, recording the amount of energy used during on-peak and off-peak
hours.
Solid-state design
Fig 5: - Solid state electricity meter used in a home in the Netherlands.
As in the block diagram, the meter has a power supply, a metering engine, a processing and
communication engine (i.e. a microcontroller), and other add-on modules such as RTC, LCD,

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communication ports/modules and so on. The metering engine is given the voltage and current
inputs and has a voltage reference, samplers and quantizes followed by an ADC section to yield
the digitized equivalents of all the inputs. These inputs are then processed using a digital signal
processor to calculate the various metering parameters.
The largest source of long-term errors in the meter is drift in the preamp, followed by the
precision of the voltage reference. Both of these vary with temperature as well, and vary wildly
because most meters are outdoors. Characterizing and compensating for these is a major part of
meter design. The processing and communication section has the responsibility of calculating the
various derived quantities from the digital values generated by the metering engine. This also has
the responsibility of communication using various protocols and interface with other add on
modules connected as slaves to it.
RTC and other add-on modules are attached as slaves to the processing and communication
section for various input/output functions. On a modern meter most if not all of this will be
implemented inside the microprocessor, such as the real-time clock (RTC), LCD controller,
temperature sensor, memory and analog to digital converters.
APPLICATIONS
Multiple tariff (variable rate) meters
Electricity retailers may wish to charge customers different tariffs at different times of the day to
better reflect the costs of generation and transmission. Since it is typically not cost effective to
store significant amounts of electricity during a period of low demand for use during a period of
high demand, costs will vary significantly depending on the time of day. Low cost generation
capacity (base load) such as nuclear can take many hours to start, meaning a surplus in times of
low demand, whereas high cost but flexible generating capacity (such as gas turbines) must be
kept available to respond at a moment's notice (spinning reserve) to peak demand, perhaps being
used for a few minutes per day, which is very expensive.
Some multiple tariff meters use different tariffs for different amounts of demand. These are
usually industrial meters.
Domestic usage
Domestic variable-rate meters generally permit two to three tariffs ("peak", "off-peak" and
"shoulder") and in such installations a simple electromechanical time switch may be used.
Historically, these have often been used in conjunction with electrical storage heaters or hot
water storage systems.
Multiple tariffs are made easier by time of use (TOU) meters which incorporate or are connected
to a time switch and which have multiple registers.
Switching between the tariffs may happen via ripple control, or via a radio-activated switch. In
principle, a sealed time switch can also be used, but is considered more vulnerable to tampering
to obtain cheaper electricity.

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Fig 6: - Meter and Tele switcher
Radio-activated switching is common in the UK, with a nightly data signal sent within the long
wave carrier of BBC Radio 4, 198 kHz. The time of off-peak charging is usually seven hours
between midnight and 7.00am GMT, and this is designed to power storage
heaters and immersion heaters. In the UK, such tariffs are branded Economy 7 or White Meter.
The popularity of such tariffs has declined in recent years, at least in the domestic market,
because of the (perceived or real) deficiencies of storage heaters and the comparatively low cost
of natural gas (although there remain many without the option of gas, whether they are outside
the gas supply network or cannot afford the capital cost of a radiator system). An Economy
10 meter is also available, which gives 10 hours of cheap off-peak heating spread out over three
timeslots throughout a 24-hour period. This allows multiple top-up boosts to storage heaters, or a
good spread of times to run a wet electric heating system on a cheaper electricity rate.[17]
Most meters using Economy 7 switch the entire electricity supply to the cheaper rate during the 7
hour night time period,[18] not just the storage heater circuit. The downside of this is that the
daytime rate will be significantly higher, and standing charges may be a little higher too. For
instance, normal rate electricity may be 9p per kWh, whereas Economy 7's daytime rate might be
14 to 17 p per kWh, but only 5.43p per kWh at night. Timer switches installed on washing
machines, tumble dryers, dishwashers and immersion heaters may be set so that they switch on
only when the rate is lower.
Commercial usage
Large commercial and industrial premises may use electronic meters which record power usage
in blocks of half an hour or less. This is because most electricity grids have demand surges
throughout the day, and the power company may wish to give price incentives to large customers
to reduce demand at these times. These demand surges often correspond to meal times or,
famously, to advertisements interrupting popular television programme.
Appliance energy meters
Plug in electricity meters (or "Plug load" meters) measure energy used by individual appliances.
There are a variety of models available on the market today but they all work on the same basic
principle. The meter is plugged into an outlet, and the appliance to be measured is plugged into
the meter. Such meters can help in energy conservation by identifying major energy users, or
devices that consume excessive standby power. Web resources can also be used, if an estimate of
the power consumption is enough for the research purposes power meter can often be borrowed
from the local power authorities or a local public library.

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In-home energy use displays
A potentially powerful means to reduce household energy consumption is to provide convenient
real-time feedback to users so they can change their energy using behavior. Recently, low-cost
energy feedback displays have become available. A study using a consumer-readable meter in
500 Ontario homes by Hydro One showed an average 6.5% drop in total electricity use when
compared with a similarly sized control group. Hydro One subsequently offered free power
monitors to 30,000 customers based on the success of the pilot.[23] Projects such as Google
Power Meter, take information from a smart meter and make it more readily available to users to
help encourage conservation.[24]
Smart meters
Smart meters go a step further than simple AMR (automatic meter reading). They offer
additional functionality including a real-time or near real-time reads, power outage notification,
and power quality monitoring. They allow price setting agencies to introduce different prices for
consumption based on the time of day and the season. Another type of smart meter
uses nonintrusive load monitoring to automatically determine the number and type of appliances
in a residence,
how much energy each uses and when. This meter is used by electric utilities to do surveys of
energy use. It eliminates the need to put timers on all of the appliances in a house to determine
how much energy each uses.
Prepayment meters
Fig 7: -Prepayment meter
Prepayment meter and magnetic stripe tokens, from a rented accommodation in the UK. The
button labeled A displays information and statistics such as current tariff and remaining credit.
The button labeled B activates a small amount of emergency credit should the customer run out.
Fig 8: - prepayment key

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The standard business model of electricity retailing involves the electricity company billing the
customer for the amount of energy used in the previous month or quarter. In some countries, if
the retailer believes that the customer may not pay the bill, a prepayment meter may be installed.
This requires the customer to make advance payment before electricity can be used.[citation needed]If
the available credit is exhausted then the supply of electricity is cut off by a relay.
In the UK, mechanical prepayment meters used to be common in rented accommodation.
Disadvantages of these included the need for regular visits to remove cash, and risk of theft of
the cash in the meter.
Modern solid-state electricity meters, in conjunction with smart cards, have removed these
disadvantages and such meters are commonly used for customers considered to be a poor credit
risk. In the UK, customers can use organization such as the Post Office Ltd or Pay
Point network, where rechargeable tokens (Quantum cards for natural gas, or plastic "keys" for
electricity) can be loaded with whatever money the customer has available.
In South Africa, Sudan and Northern Ireland prepaid meters are recharged by entering a unique,
encoded twenty digit number using a keypad. This makes the tokens, essentially a slip of paper,
very cheap to produce.
Around the world, experiments are going on, especially in developing countries, to test pre-
payment systems. In some cases, prepayment meters have not been accepted by customers. There
are various groups, such as the Standard Transfer Specification (STS) association, which
promote common standards for prepayment metering systems across manufacturers. Prepaid
meters using the STS standard are used in many countries.
Time of day metering
Time of Day metering (TOD), also known as Time of Usage (TOU) or Seasonal Time of Day
(SToD), metering involves dividing the day, month and year into tariff slots and with higher
rates at peak load periods and low tariff rates at off-peak load periods. While this can be used to
automatically control usage on the part of the customer (resulting in automatic load control), it is
often simply the customer's responsibility to control his own usage, or pay accordingly
(voluntary load control). This also allows the utilities to plan their transmission infrastructure
appropriately. See also Demand-side Management (DSM).
TOD metering normally splits rates into an arrangement of multiple segments including on-peak,
off-peak, mid-peak or shoulder, and critical peak. A typical arrangement is a peak occurring
during the day (non-holiday days only), such as from 1 pm to 9 pm Monday through Friday
during the summer and from 6:30 am to 12 noon and 5 pm to 9 pm during the winter. More
complex arrangements include the use of critical peaks which occur during high demand periods.
The times of peak demand/cost will vary in different markets around the world.
Large commercial users can purchase power by the hour using either forecast pricing or real time
pricing. Some utilities allow residential customers to pay hourly rates, such as in Illinois, which
uses day ahead pricing.
Power export metering
Many electricity customers are installing their own electricity generating equipment, whether for
reasons of economy, redundancy or environmental reasons. When a customer is generating more
electricity than required for his own use, the surplus may be exported back to the power grid.

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Customers that generate back into the "grid" usually must have special equipment and safety
devices to protect the grid components (as well as the customer's own) in case of faults (electrical
short circuits) or maintenance of the grid (say voltage on a downed line coming from an
exporting customers facility).
This exported energy may be accounted for in the simplest case by the meter running backwards
during periods of net export, thus reducing the customer's recorded energy usage by the amount
exported. This in effect results in the customer being paid for his/her exports at the full retail
price of electricity. Unless equipped with a ratchet or equivalent, a standard meter will accurately
record power flow in each direction by simply running backwards when power is exported.
Where allowed by law, utilities maintain a profitable margin between the price of energy
delivered to the consumer and the rate credited for consumer-generated energy that flows back to
the grid. Lately, upload sources typically originate from renewable sources (e.g., wind
turbines, photovoltaic cells), or gas or steam turbines, which are often found
in cogeneration systems. Another potential upload source that has been proposed is plug-in
hybrid car batteries (vehicle-to-grid power systems). This requires a "smart grid," which includes
meters that measure electricity via communication networks that require remote control and give
customers timing and pricing options. Vehicle-to-grid systems could be installed at
workplace parking lots and garages and at park and rides and could help drivers charge their
batteries at home at night when off-peak power prices are cheaper, and receive bill crediting for
selling excess electricity back to the grid during high-demand hours.
3.2 GSM MODEM
 GSM (Global System for Mobile Communications)
originally Group Special Mobile is a standard developed by the European Telecommunications
Standards Institute (ETSI) to describe the protocols for second generation (2G) digital cellular
networks used by mobile phones, first deployed in Finland in July 1991. As of 2014 it has
become the de facto global standard for mobile communications with over 90% market share
operating in over 219 countries and territories. 2G networks developed as a replacement for first
generation (1G) analogue cellular networks and the GSM standard originally described a digital
circuit switched network optimized for full duplex voice telephony. This expanded over time to
include data communications, first by circuit-switched transport then by packet data transport via
GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution or
EGPRS).
Subsequently the 3GPP developed third-generation (3G) UMTS standards followed by fourth-
generation (4G) LTE Advanced standards which do not form part of the ETSI GSM standard.
"GSM" is a trademark owned by the GSM Association. It may also refer to the (initially) most
common voice codec used, Full Rate.

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Technical details
Fig 9: -Structure of a GSM modem
Fig 10:- GSM Modem

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The network is structured into a number of discrete sections:
 Base Station Subsystem: -the base stations and their controllers explained
 Network and Switching Subsystem:-the part of the network most similar to a fixed
network, sometimes just called the "core network"
 GPRS Core Network – the optional part which allows packet-based Internet connections
Operations support system (OSS) – network maintenance
Fig 11:- Base station subsystem
GSM is a cellular network, which means that cell phones connect to it by searching for cells in
the immediate vicinity. There are five different cell sizes in a GSM network macro, micro, pico,
femto, and umbrella cells. The coverage area of each cell varies according to the implementation
environment. Macro cells can be regarded as cells where the base station antenna is installed on a
mast or a building above average rooftop level. Micro cells are cells whose antenna height is
under average rooftop level; they are typically used in urban areas. Pico cells are small cells
whose coverage diameter is a few dozen metres they are mainly used indoors. Femto cells are
cells designed for use in residential or small business environments and connect to the service
provider’s network via a broadband internet connection. Umbrella cells are used to cover
shadowed regions of smaller cells and fill in gaps in coverage between those cells. Cell
horizontal radius varies depending on antenna height, antenna gain, and propagation conditions
from a couple of hundred meters to several tens of kilometres. The longest distance the GSM
specification supports in practical use is 35 kilometres. There are also several implementations of
the concept of an extended cell, where the cell radius could be double or even more depending
on the antenna system the type of terrain and the timing advance.

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GSM carrier frequencies
GSM networks operate in a number of different carrier frequency ranges (separated into GSM
frequency ranges for 2G and UMTS frequency bands for 3G), with most 2G GSM networks
operating in the 900 MHz or 1800 MHz bands. Where these bands were already allocated, the
850 MHz and 1900 MHz bands were used instead (for example in Canada and the United
States). In rare cases the 400 and 450 MHz frequency bands are assigned in some countries
because they were previously used for first-generation systems.
Most 3G networks in Europe operate in the 2100 MHz frequency band. For more information
on worldwide GSM frequency usage, see GSM frequency bands. Regardless of the frequency
selected by an operator, it is divided into timeslots for individual phones. This allows eight
full-rate or sixteen half-rate speech channels per radio frequency. These eight radio timeslots
(or burst periods) are grouped into a TDMA frame. Half-rate channels use alternate frames in
the same timeslot. The channel data rate for all 8 channels is 270.833 k bit/s, and the frame
duration is 4.615 ms. The transmission power in the handset is limited to a maximum of 2
watts in GSM 850/900 and 1 watt in GSM 1800/1900.
Subscriber Identity Module (SIM)
One of the key features of GSM is the Subscriber Identity Module commonly known as a SIM
card. The SIM is a detachable smart card containing the user’s subscription information and
phone book. This allows the user to retain his or her information after switching handsets.
Alternatively the user can also change operators while retaining the handset simply by
changing the SIM. Some operators will block this by allowing the phone to use only a single
SIM or only a SIM issued by them this practice is known as SIM locking.
GSM security
GSM was intended to be a secure wireless system. It has considered the user authentication
using a pre-shared key and challenge-response, and over-the-air encryption. However, GSM
is vulnerable to different types of attack, each of them aimed at a different part of the network.
The development of UMTS introduces an optional Universal Subscriber Identity Module
(USIM), that uses a longer authentication key to give greater security, as well as mutually
authenticating the network and the user, whereas GSM only authenticates the user to the
network (and not vice versa). The security model therefore offers confidentiality and
authentication, but limited authorization capabilities and no non-repudiation. GSM uses
General Packet Radio Service (GPRS) for data transmissions like browsing the web. The most
commonly deployed GPRS ciphers were publicly broken in 2011. The researchers revealed
flaws in the commonly used GEA/1 and GEA/2 ciphers and published the open-source
"GPRS decode" software for sniffing GPRS networks. They also noted that some carriers do
not encrypt the data (i.e., using GEA/0) in order to detect the use of traffic or protocols they
do not like (e.g., Skype), leaving customers unprotected. GEA/3 seems to remain relatively
hard to break and is said to be in use on some more modern networks. If used with USIM to
prevent connections to fake base stations and downgrade attacks, users will be protected in the
medium term, though migration to 128-bit GEA/4 is still recommended.

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Standards information
The GSM systems and services are described in a set of standards governed by ETSI, where a
full list is maintained.
3.3 NANO ARDUINO
The Arduino Nano is a small, complete, and breadboard-friendly board based on
the ATmega328 (Arduino Nano 3.x) or ATmega168 (Arduino Nano 2.x). It has more or less
the same functionality of the Arduino Duemilanove, but in a different package. It lacks only a
DC power jack, and works with a Mini-B USB cable instead of a standard one. The Nano was
designed and is being produced by Gravitech.
Fig 12: - Nano arduino
Schematic and Design
Arduino Nano 3.0 (ATmega328): schematic, Eagle files.
Arduino Nano 2.3 (ATmega168): manual (pdf), Eagle files. Note: since the free version of Eagle
does not handle more than 2 layers, and this version of the Nano is 4 layers, it is published here
unrouted, so users can open and use it in the free version of Eagle.
Specifications
Microcontroller Atmel ATmega168 or ATmega328
Operating Voltage (logic
level)
5 V
Input Voltage 7-12 V

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(recommended)
Input Voltage (limits) 6-20 V
Digital I/O Pins 14 (of which 6 provide PWM output)
Analog Input Pins 8
DC Current per I/O Pin 40 mA
Flash Memory
16 KB (ATmega168) or 32 KB (ATmega328) of which 2 KB used by
bootloader
SRAM 1 KB (ATmega168) or 2 KB (ATmega328)
EEPROM 512 bytes (ATmega168) or 1 KB (ATmega328)
Clock Speed 16 MHz
Dimensions 0.73" x 1.70"
Length 45 mm
Width 18 mm
Weigth 5 g
Power
The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external
power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is
automatically selected to the highest voltage source.
Memory
The ATmega168 has 16 KB of flash memory for storing code (of which 2 KB is used for the
bootloader); the ATmega328 has 32 KB, (also with 2 KB used for the bootloader).
The ATmega168 has 1 KB of SRAM and 512 bytes of EEPROM (which can be read and written
with the EEPROM library); the ATmega328 has 2 KB of SRAM and 1 KB of EEPROM.
Input and Output
Each of the 14 digital pins on the Nano can be used as an input or output, using pin
Mode(), digital Write(), and digital Read() functions. They operate at 5 volts. Each pin can
provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by
default) of 20-50 kOhms. In addition, some pins have specialized functions:
 Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. These pins
are connected to the corresponding pins of the FTDI USB-to-TTL Serial chip.
 External Interrupts: 2 and 3. These pins can be configured to trigger an interrupt on a low value,
a rising or falling edge, or a change in value. See the attach Interrupt() function for details.
 PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analog Write() function.

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 SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI communication, which,
although provided by the underlying hardware, is not currently included in the Arduino
language.
 LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH value, the
LED is on, when the pin is LOW, it's off.
The Nano has 8 analog inputs, each of which provide 10 bits of resolution (i.e. 1024 different
values). By default they measure from ground to 5 volts, though is it possible to change the
upper end of their range using the analog Reference() function. Analog pins 6 and 7 cannot be
used as digital pins. Additionally, some pins have specialized functionality:
 I2C: A4 (SDA) and A5 (SCL). Support I2C (TWI) communication using the Wire
library (documentation on the Wiring website).
There are a couple of other pins on the board:
 AREF. Reference voltage for the analog inputs. Used with analog Reference().
 Reset. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to
shields which block the one on the board.
See also the mapping between Arduino pins and ATmega168 ports.
Communication
The Arduino Nano has a number of facilities for communicating with a computer, another
Arduino, or other microcontrollers. The ATmega168 and ATmega328 provide UART TTL (5V)
serial communication, which is available on digital pins 0 (RX) and 1 (TX). An
FTDI FT232RL on the board channels this serial communication over USB and the FTDI
drivers (included with the Arduino software) provide a virtual com port to software on the
computer. The Arduino software includes a serial monitor which allows simple textual data to be
sent to and from the Arduino board. The RX and TX LEDs on the board will flash when data is
being transmitted via the FTDI chip and USB connection to the computer (but not for serial
communication on pins 0 and 1). A Software Serial library allows for serial communication on
any of the Nano's digital pins. The ATmega168 and ATmega328 also support I2C (TWI) and
SPI communication. The Arduino software includes a Wire library to simplify use of
the I2C bus; see the documentation for details. To use the SPI communication, please see
the ATmega168 or ATmega328 datasheet.
Programming
The Arduino Nano can be programmed with the Arduino software (download). Select "Arduino
Diecimila, Duemilanove, or Nano w/ ATmega168" or "Arduino Duemilanove or Nano
w/ ATmega328" from the Tools > Board menu (according to the microcontroller on your board).
For details, see the reference and tutorials.

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The ATmega168 or ATmega328 on the Arduino Nano comes preburned with a bootloader that
allows you to upload new code to it without the use of an external hardware programmer. It
communicates using the original STK500 protocol (reference, C header files). You can also
bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial
Programming) header using Arduino ISP or similar; see these instructions for details.
Automatic (Software) Reset
Rather than requiring a physical press of the reset button before an upload, the Arduino Nano is
designed in a way that allows it to be reset by software running on a connected computer. One of
the hardware flow control lines (DTR) of the FT232RL is connected to the reset line of
the ATmega168 or ATmega328 via a 100 nano farad capacitor. When this line is asserted (taken
low), the reset line drops long enough to reset the chip. The Arduino software uses this capability
to allow you to upload code by simply pressing the upload button in the Arduino environment.
This means that the boot loader can have a shorter timeout, as the lowering of DTR can be well-
coordinated with the start of the upload.
This setup has other implications. When the Nano is connected to either a computer running Mac
OS X or Linux, it resets each time a connection is made to it from software (via USB). For the
following half-second or so, the boot loader is running on the Nano. While it is programmed to
ignore malformed data (i.e. anything besides an upload of new code), it will intercept the first
few bytes of data sent to the board after a connection is opened. If a sketch running on the board
receives one-time configuration or other data when it first starts, make sure that the software with
which it communicates waits a second after opening the connection and before sending this data.
3.4 TRANSFORMER
Transformers convert AC electricity from one voltage to another with a little loss of power. Step-
up transformers increase voltage, step-down transformers reduce voltage. Most power supplies
use a step-down transformer to reduce the dangerously high voltage to a safer low voltage.
Fig 13:- typical transformer
The input coil is called the primary and the output coil is called the secondary. There is no
electrical connection between the two coils; instead they are linked by an alternating magnetic
field created in the soft-iron core of the transformer. The two lines in the middle of the circuit

26. Page | 26
symbol represent the core. Transformers waste very little power so the power out is (almost)
equal to the power in. Note that as voltage is stepped down and current is stepped up.
The ratio of the number of turns on each coil, called the turn‘s ratio, determines the ratio of the
voltages. A step-down transformer has a large number of turns on its primary (input) coil which
is connected to the high voltage mains supply, and a small number of turns on its secondary
(output) coil to give a low output voltage.
TURNS RATIO = (Vp / Vs) = ( Np / Ns )
Where,
Vp = primary (input)
voltage. Vs = secondary
(output) voltage
Np = number of turns on
primary coil Ns = number of
turns on secondary coil Ip =
primary (input) current
Is = secondary (output) current.
Ideal power equation
Fig14: - Ideal transformer as a circuit element
If the secondary coil is attached to a load that allows current to flow, electrical power is
transmitted from the primary circuit to the secondary circuit. Ideally, the transformer is perfectly
efficient; all the incoming energy is transformed from the primary circuit to the magnetic field
and into the secondary circuit. If this condition is met, the incoming electric power must equal

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the outgoing power:
Giving the ideal transformer equation
Transformers normally have high efficiency, so this formula is a reasonable approximation.
If the voltage is increased, then the current is decreased by the same factor. The impedance in
one circuit is transformed by the square of the turns ratio. For example, if an impedance Zs is
attached across the terminals of the secondary coil, it appears to the primary circuit to have an
impedance of (Np/Ns)2Zs. This relationship is reciprocal, so that the impedance Zp of the primary
circuit appears to the secondary to be (Ns/Np)2Zp.
3.5 VOLTAGE REGULATOR (7805)
Features
• Output Current up to 1A.
• Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V.
• Thermal Overload Protection.
• Short Circuit Protection.
• Output Transistor Safe Operating Area Protection.
Fig 15: - Voltage regulator

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Description
The LM78XX/LM78XXA series of three-terminal positive regulators are available in the TO-
220/D-PAK package and with several fixed output voltages, making them useful in a Wide range
of applications. Each type employs internal current limiting, thermal shutdown and safe
operating area protection, making it essentially indestructible. If adequate heat sinking is
provided, they can deliver over 1A output Current. Although designed primarily as fixed voltage
regulators, these devices can be used with external components to obtain adjustable voltages and
currents.
Features
• Output Current up to 1A.
• Output Voltages of 5, 6, 8, 9, 10, 12, 15, 18, 24V.
• Thermal Overload Protection.
• Short Circuit Protection.
• Output Transistor Safe Operating Area Protection.
Internal Block Diagram
Fig 16: -Block diagram of voltage regulator

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Absolute Maximum Ratings
Table 1: -Ratings of the voltage regulator
3.6 FULL WAVE BRIDGE RECTIFIERS
A Full wave rectifier is a circuit arrangement which makes use of both half cycles of input
alternating current (AC) and converts them to direct current (DC). In our tutorial on half wave
rectifiers, we have seen that a half wave rectifier makes use of only one half cycle of the input
alternating current. Thus a full wave rectifier is much more efficient (double+) than a half wave
rectifier. This process of converting both half cycles of the input supply (alternating current) to
direct current (DC) is termed full wave rectification. Full wave rectifier can be constructed in 2
ways. The first method makes use of a center tapped transformer and 2 diodes. This arrangement
is known as Centre Tapped Full Wave Rectifier. The second method uses a normal transformer
with 4 diodes arranged as a bridge. This arrangement is known as a Bridge Rectifier.
Full Wave Rectifier Working & Operation
The working & operation of a full wave bridge rectifier is pretty simple. The circuit diagrams
and wave forms we have given below will help you understand the operation of a bridge rectifier
perfectly. In the circuit diagram, 4 diodes are arranged in the form of a bridge. The transformer
secondary is connected to two diametrically opposite points of the bridge at points A & C. The
load resistance RL is connected to bridge through points B and D.

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Fig 17: -Full Wave Bridge Rectifier Circuit Diagram with Input and Output Wave Forms

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During the first half cycle
During first half cycle of the input voltage, the upper end of the transformer secondary winding
is positive with respect to the lower end. Thus during the first half cycle diodes D1 and D3 are
forward biased and current flows through arm AB, enters the load resistance RL, and returns back
flowing through arm DC. During this half of each input cycle, the diodes D2 and D4 are reverse
biased and current is not allowed to flow in arms AD and BC. The flow of current is indicated by
solid arrows in the figure above. We have developed another diagram below to help you
understand the current flow quickly. Current flow from source (transformer secondary) to the
load resistance. The red arrows indicate return path of current from load resistance to the source,
thus completing the circuit.
Fig 18: -Flow of current in Bridge Rectifier
During the second half cycle
During second half cycle of the input voltage, the lower end of the transformer secondary
winding is positive with respect to the upper end. Thus diodes D2 and D4 become forward biased
and current flows through arm CB, enters the load resistance RL, and returns back to the source
flowing through arm DA. Flow of current has been shown by dotted arrows in the figure. Thus
the direction of flow of current through the load resistance RL remains the same during both half
cycles of the input supply voltage. See the diagram below the green arrows indicate beginning
of current flow from ource (transformer secondary) to the load resistance. The red arrows
indicate return path of current from load resistance to the source, thus completing the circuit.

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Fig 19: -Path of current in 2nd Half Cycle
Peak Inverse Voltage of a Full wave bridge rectifier
Let’s analysis peak inverse voltage (PIV) of a full wave bridge rectifier using the circuit diagram.
At any instant when the transformer secondary voltage attains positive peak value Vmax, diodes
D1 and D3 will be forward biased (conducting) and the diodes D2 and D4 will be reverse biased
(non-conducting). If we consider ideal diodes in bridge, the forward biased diodes D1 and D3
will have zero resistance. This means voltage drop across the conducting diodes will be zero.
This will result in the entire transformer secondary voltage being developed across load
resistance RL.
Thus PIV of a bridge rectifier = Vmax (max of secondary voltage)
Bridge Rectifier Circuit Analysis
The only difference in the analysis between full wave and Centre tap rectifier is that
1. In a bridge rectifier circuit two diodes conduct during each half cycle and the forward
resistance becomes double (2RF).
2. In a bridge rectifier circuit Vsmax is the maximum voltage across the transformer
secondary winding whereas in a centre tap rectifier Vsmax represents that maximum
voltage across each half of the secondary winding.

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The different parameters are explained with equations below:
1. Peak Current
Instantaneous value of the voltage applied to the rectifier is given as
vs = Vsmax Sin wt
If the diode is assumed to have a forward resistance of RF ohms and a reverse resistance
equal to infinity, then current flowing through the load resistance is given as
i1 = Imax Sin wt and i2 = 0 for the first half cycle
and i1 = 0 and i2 = Imax Sin wt for second half cycle
The total current flowing through the load resistance RL, being the sum of currents i1 and i2
is given as
i = i1 + i2 = Imax Sin wt for the whole cycle.
Where peak value of the current flowing through the load resistance RL is given as
Imax = Vsmax/(2RF + RL)
2. Output Current
Since the current is the same through the load resistance RL in the two halves of the ac
cycle, magnitude od dc current Idc, which is equal to the average value of ac current, can
be obtained by integrating the current i1 between 0 and pi or current i2 between pi and
2pi.
Output Current of Full Wave Rectifier
3. DC Output Voltage
Average or dc value of voltage across the load is given as
DC Output Voltage of Full Wave Rectifier
4. Root Mean Square (RMS) Value of Current

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RMS or effective value of current flowing through the load resistance RL is given as
RMS Value of Current of Full Wave Rectifier
5. Root Mean Square (RMS) Value of Output Voltage
RMS value of voltage across the load is given as
RMS Value of Output Voltage of Full Wave Rectifier
6. Rectification Efficiency
Power delivered to load,
Rectification Efficiency of Full Wave Rectifier
7. Ripple Factor
Form factor of the rectified output voltage of a full wave rectifier is given as
Ripple Factor of Full Wave Rectifier

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So, ripple factor, γ = 1.112 – 1) = 0.482
8. Regulation
The dc output voltage is given as
Full Wave Bridge Rectifier with Capacitor Filter
Output of full wave rectifier is not a constant DC voltage. You can observe from the output
diagram that it’s a pulsating dc voltage with ac ripples. In real life applications, we need a power
supply with smooth wave forms. In other words, we desire a DC power supply with constant
output voltage. A constant output voltage from the DC power supply is very important as it
directly impacts the reliability of the electronic device we connect to the power supply. We can
make the output of full wave rectifier smooth by using a filter (a capacitor filter or an inductor
filter) across the diode. In some cases a resistor-capacitor coupled filter (RC) is also used. The
circuit diagram below shows a half wave rectifier with capacitor filter.
Fig 20: -Full Wave Rectifier with Capacitor Filter

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Ripple factor in a bridge rectifier
Ripple factor is a ratio of the residual ac component to dc component in the output voltage.
Ripple factor in a bridge rectifier is half than that of a half wave rectifier.
 Light-emitting diode (LED)
It is a two lead semiconductor light source. It is a p–n junction diode, which emits light when
activated. When a suitable voltage is applied to the leads, 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 colour of the light (corresponding to the energy of the photon) is
determined by the energy band gap of the semiconductor. An LED is often small in area (less
than 1 mm2) and integrated optical components may be used to shape its radiation pattern.
Appearing as practical electronic components in 1962 the earliest LEDs emitted low-intensity
infrared light. Infrared LEDs are still frequently used as transmitting elements in remote-control
circuits, such as those in remote controls for a wide variety of consumer electronics. The first
visible-light LEDs were also of low intensity and limited to red. Modern LEDs are available
across the visible, ultraviolet, and infrared wavelengths, with very high brightness. Early LEDs
were often used as indicator lamps for electronic devices, replacing small incandescent bulbs.
They were soon packaged into numeric readouts in the form of seven-segment displays and were
commonly seen in digital clocks.
 Register (processor register, CPU register)
A processor register (CPU register) is one of a small set of data holding places that are part of the
computer processor. A register may hold an instruction a storage address or any kind of data
(such as a bit sequence or individual characters). Some instructions specify registers as part of
the instruction. For example: an instruction may specify that the contents of two defined registers
be added together and then placed in a specified register. A register must be large enough to hold
an instruction for example: in a 64-bit computer a register must be 64 bits in length. In some
computer designs there are smaller registers for example: half-registers for shorter instructions.
Depending on the processor design and language rules registers may be numbered or have
arbitrary names. A processor typically contains multiple index registers, also known as address
registers or registers of modification. The effective address of any entity in a computer includes
the base, index and relative addresses all of which are stored in the index register. A shift register
is another type. Bits enter the shift register at one end and emerge from the other end. Flip flops
also known as bi stable gates store and process the data.
 12 volt power supply
Have you ever needed a 12 volt power supply that can supply maximum 1 amp? But trying to
buy one from the store is a little too expensive? Well, you can make a 12 volt power supply very
cheaply and easily!
I needed a 12 volt power supply for my project, the SSTC (Solid State Tesla Coil), and also
made this instruct able because it might be use full to someone...

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Things that you will need...
Fig 21:- Power supply component
Things that you will need to make this power supply is
 Piece of PCB board
 Four 1N4001 diodes
 LM7812 regulator
 Transformer that has an output of 14v - 35v AC with an output current between 100mA
to 1A, depending how much power you will need. (I found a 16v 200mA transformer in a
broken alarm clock.)
 1000uF - 4700uF capacitor
 1uF capacitor
 Two 100nF capacitors
 Jumper wires (I used some plain wire as jumper wires)
 Heat sink (optional)

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You should be able you get most (maybe all) of the parts at Radio Shack or Maplin.
3.7 LCD DISPLAY(16*2)
 Liquid crystal display (LCD)
Description Additional Images (1) Reviews (0) Related Products (0) It is an electronically-
modulated optical device made up of any number of pixels filled with liquid crystals
Alphanumeric LCD (16X2)
A liquid crystal display (LCD) is a thin, flat electronic visual display that uses the light
modulating properties of liquid crystals (LCs). They are used in a wide range of applications
including computer, monitors, television, instrument panels, aircraft, cockpit display, signage
etc.
Fig 22: - Liquid crystal oscillator
FEATURES
 A liquid crystal display (LCD) is a thin, flat electronic visual display that uses the light
modulating properties of liquid crystals (LCs).
 They are used in a wide range of applications including: computer monitors, television,
instrument panels, aircraft, cockpit display, signage, etc.
 LCDs are more energy efficient and offer safer disposal than CRTs
 It is an electronically modulated device made up of any number of pixels filled with
liquid crystals
3.8 RESISTOR
A resistor is a two-terminal electronic component designed to oppose an electric current by
producing a voltage drop between its terminals in proportion to the current, that is, in accordance

39. Page | 39
with Ohm's law:
V = IR
Resistors are used as part of electrical networks and electronic circuits. They are extremely
commonplace in most electronic equipment. Practical resistors can be made of various
compounds and films, as well as resistance wire (wire made of a high-resistivity alloy, such as
nickel/chrome).
Fig 23: - Registers
The primary characteristics of resistors are their resistance and the power they can dissipate.
Other characteristics include temperature coefficient, noise, and inductance. Less well-known is
critical resistance, the value below which power dissipation limits the maximum permitted
current flow, and above which the limit is applied voltage. Critical resistance depends upon the
materials constituting the resistor as well as its physical dimensions; it's determined by design.
Resistors can be integrated into hybrid and printed circuits, as well as integrated circuits. Size,
and position of leads (or terminals) are relevant to equipment designers; resistors must be
physically large enough not to overheat when dissipating their power.
A resistor is a two- terminal passive electronic component which implements electrical
resistance as a circuit element. When a voltage V is applied across the terminals of a resistor, a
current I will flow through the resistor in direct proportion to that voltage. The reciprocal of the
constant of proportionality is known as the resistance R, since, with a given voltage V, a larger
value of R further "resists" the flow of current I as given by Ohm's law:

40. Page | 40
Resistors are common elements of electrical networks and electronic circuits and are ubiquitous
in most electronic equipment. Practical resistors can be made of various compounds and films, as
well as resistance wire (wire made of a high-resistivity alloy, such as nickel-chrome). Resistors
are also implemented within integrated circuits, particularly analog devices, and can also be
integrated into hybrid and printed circuits.
The electrical functionality of a resistor is specified by its resistance: common
commercial resistors are manufactured over a range of more than 9 orders of magnitude. When
specifying that resistance in an electronic design, the required precision of the resistance may
require attention to the manufacturing tolerance of the chosen resistor, according to its specific
application. The temperature coefficient of the resistance may also be of concern in some
precision applications. Practical resistors are also specified as having a maximum power rating
which must exceed the anticipated power dissipation of that resistor in a particular circuit: this is
mainly of concern in power electronics applications. Resistors with higher power ratings are
physically larger and may require heat sinking. In a high voltage circuit, attention must
sometimes be paid to the rated maximum working voltage of the resistor.
The series inductance of a practical resistor causes its behavior to depart from ohms law;
this specification can be important in some high-frequency applications for smaller values of
resistance. In a low-noise amplifier or pre-amp the noise characteristics of a resistor may be an
issue. The unwanted inductance, excess noise, and temperature coefficient are mainly dependent
on the technology used in manufacturing the resistor. They are not normally specified
individually for a particular family of resistors manufactured using a particular technology. A
family of discrete resistors is also characterized according to its form factor, that is, the size of
the device and position of its leads (or terminals) which is relevant in the practical manufacturing
of circuits using them.

41. Page | 41
Units
The ohm (symbol: Ω) is the SI unit of electrical resistance, named after Georg Simon Ohm.
An ohm is equivalent to a volt per ampere. Since resistors are specified and manufactured over
a very large range of values, the derived units of milliohm (1 mΩ = 10−3 Ω), kilohm (1 kΩ = 103
Ω), and megohm (1 MΩ = 106 Ω) are also in common usage.
The reciprocal of resistance R is called conductance G = 1/R and is measured in
Siemens (SI unit), sometimes referred to as a mho. Thus a Siemens is the reciprocal of an ohm:
S = Ω − 1. Although the concept of conductance is often used in circuit analysis, practical
resistors are always specified in terms of their resistance (ohms) rather than conductance.
Theory of operation
Ohm's law
The behavior of an ideal resistor is dictated by the relationship specified in Ohm's law:
Ohm's law states that the voltage (V) across a resistor is proportional to the current (I) passing
through it, where the constant of proportionality is the resistance (R).
Equivalently, Ohm's law can be stated:
This formulation of Ohm's law states that, when a voltage (V) is present across a resistance (R), a
current (I) will flow through the resistance. This is directly used in practical computations. For
example, if a 300 ohm resistor is attached across the terminals of a 12 volt battery, then a
current of 12 / 300 = 0.04 amperes (or 40 milliamperes) will flow through that resistor.
Series and parallel resistors
In a series configuration, the current through all of the resistors is the same, but the
voltage across each resistor will be in proportion to its resistance. The potential difference
(voltage) seen across the network is the sum of those voltages, thus the total resistance can be
found as the sum of those resistances:

42. Page | 42
3.9 CAPACITORS
A capacitor or condenser is a passive electronic component consisting of a pair of
conductors separated by a dielectric. When a voltage potential difference exists between the
conductors, an electric field is present in the dielectric. This field stores energy and produces a
mechanical force between the plates. The effect is greatest between wide, flat, parallel, narrowly
separated conductors.
Fig 24: - Capacitors
An ideal capacitor is characterized by a single constant value, capacitance, which is measured in
farads. This is the ratio of the electric charge on each conductor to the potential difference
between them. In practice, the dielectric between the plates passes a small amount of leakage
current. The conductors and leads introduce an equivalent series resistance and the dielectric has

43. Page | 43
an electric field strength limit resulting in a breakdown voltage. The properties of capacitors in a
circuit may determine the resonant frequency and quality factor of a resonant circuit, power
dissipation and operating frequency in a digital logic circuit, energy capacity in a high-power
system, and many other important aspects.
A capacitor (formerly known as condenser) is a device for storing electric charge. The forms of
practical capacitors vary widely, but all contain at least two conductors separated by a non-
conductor. Capacitors used as parts of electrical systems, for example, consist of metal foils
separated by a layer of insulating film.
Capacitors are widely used in electronic circuits for blocking direct current while allowing
alternating current to pass, in filter networks, for smoothing the output of power supplies, in the
resonant circuits that tune radios to particular frequencies and for many other purposes. A
capacitor is a passive electronic component consisting of a pair of conductors separated by a
dielectric (insulator). When there is a potential difference (voltage) across the conductors, a
static electric field develops in the dielectric that stores energy and produces a mechanical force
between the conductors. 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.
The capacitance is greatest when there is a narrow separation between large areas of
conductor, hence capacitor conductors are often called "plates", referring to an early means of
construction. In practice the dielectric between the plates passes a small amount of leakage
current and also has an electric field strength limit, resulting in a breakdown voltage, while the
conductors and leads introduce an undesired inductance and resistance.
Theory of operation
Capacitance

44. Page | 44
Charge separation in a parallel-plate capacitor causes an internal electric field. A dielectric
(orange) reduces the field and increases the capacitance.
 Button holder
For buttons, switches and indicators with metal or plastic flange Ø22 of the Tem technique XB4
/ XB5 type. Depth under rail 60 mm (same as products in the multi 9 range). Drilling diameter
Ø22.3. Self-extinguishing insulating material. Colour: light grey RAL
 Universal holder
For buttons, indicators, light emitting diodes (LED) and potentiometers. Easy drilling to be
adapted depending on use. Depth under rail 60 mm(same as products in the multi 9 range). Self-
extinguishing insulating material. Colour: light grey RAL
 Extension board
A power strip (also known as an extension block, power board, power bar, plug board, trailing
gang, trailing socket, trailer lead and by many other variations) is a block of electrical sockets
that attaches to the end of a flexible cable (typically with a mains plug on the other end),
allowing multiple electrical

45. Page | 45
 RESULT
In this project we interface the GSM (Global system for mobile communication)
with nano ardiuno and sim put in GSM module .
And with the help of studio programming we set a Mobile number on which we
want to send message of that how much electric power is used by us.
Blinking of LED of digital meter takes pulse and counter count every pulse and
show the result on LCD .When we do misscall on mobile number then GSM send
the message on set mobile number.

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 REFERENCE
1. Ricks, G.W.D. (March 1896). "Electricity Supply Meters". Journal of the Institution of
Electrical Engineers. 25 (120): 57–77. doi:10.1049/jiee-1.1896.0005. Student paper read
on January 24, 1896 at the Students' Meeting.
2. The Electrical engineer, Volume 5. (February, 1890)
3. The Electrician, Volume 50. 1923
4. Official gazette of the United States Patent Office: Volume 50. (1890)
5. W. Bernard Carlson, Innovation as a Social Process: Elihu Thomson and the Rise of
General Electric, Cambridge University Press, 2003 ISBN 0-521-53312-0
6. https://www.arduino.cc/en/Main/ArduinoBoardNano
7. Horowitz, Paul; Hill, Winfield (1989). The Art of Electronics (Second ed.). Cambridge
University Press. pp. 44–47. ISBN 0-521-37095-7.
8. British patent 24398
9. D.R.P. and D.R.G.M.".
10. Strzelecki, R. Power Electronics in Smart Electrical Energy Networks. Springer, 2008, p.
57.
11. "Graetz Flow Control Circuit".
12. Harder, Douglas Wilhelm. "Resistors: A Motor with a Constant Force (Force Source)".
Department of Electrical and Computer Engineering, University of Waterloo. Retrieved 9
November 2014.
13. Farago, PS, An Introduction to Linear Network Analysis, pp. 18–21, The English
Universities Press Ltd, 1961.
14. Wu, F. Y. (2004). "Theory of resistor networks: The two-point resistance". Journal of
Physics A: Mathematical and General. 37 (26): 6653. doi:10.1088/0305-4470/37/26/004.
15. Wu, Fa Yueh; Yang, Chen Ning (2009). Exactly Solved Models: A Journey in Statistical
Mechanics : Selected Papers with Commentaries (1963–2008). World Scientific.
pp. 489–. ISBN 978-981-281-388-
16. US 2800616, Becker, H.I., "Low voltage electrolytic capacitor", issued 1957-07-23
17. A brief history of supercapacitors AUTUMN 2007 Batteries & Energy Storage
Technology
18. Hammond, Percy (1964). Electromagnetism for Engineers: An Introductory Course. The
Commonwealth and International Library of Science, Technology, Engineering and

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