Prepared By:                                                             
                              KUMAWAT AJAY .S              (136120324017)
                        NARIGARA DIVYANG .S     (126120324050)
                         GOHIL MAYUR .K                 (136120324011)
                         DAVE ASHUTOSH .J             (136120324004)

                                                                                      YEAR: - 2015-2016
                                                POWER ELECTRONICS DEPARTMENT
  Under the guidance of



Uninterruptedly power supply (UPS) systems are in use throughout the world, helping to supply a wide variety of critical loads, in situations of power outage or anomalies of the mains. This article describes the most common line problems and the relationship between these and the different existing kinds of UPS, showing their operation modes as well as the existent energy storage systems. It also addresses an overview of the control schemes applied to different distributed UPS configurations. Finally, it points out the applicability of such systems in distributed generation, micro grids, and renewable energy systems.


                 There are several application where even a temporarily power failure can cause a great deal of public inconvenience leading to economic losses. Examples of such applications are major computer installations, process control in chemical plants, safety monitors, general communication systems, hospital intensive care units etc. For such critical loads, it is of paramount importance to provide an UNINTERRUPTIBLE POWER SUPPLY (UPS) system so as to maintain the continuity of supply in case of power outages.

UPS stands for Uninterruptible Power Supply. It is an instrument connected between the electric grid and the consumer, comprising of electric hardware and rechargeable batteries. The aim of the instrument is to supply continuous undisturbed and conditioned power to the critical load. The energy for powering the load comes from the utility, or from the battery upon mains outage. At times, power from a wall socket is neither clean nor uninterruptible. Many abnormalities such as blackouts, brownouts, spikes, surges, and noise can occur. Under the best conditions, power interruptions can be an inconvenience. At their worst, they can cause loss of data in computer systems or damage to electronic equipment. It is the function of an Uninterruptible Power Supply (UPS) to act as a buffer and provide clean, reliable power to vulnerable electronic equipment.
            While not limited to protecting any particular type of equipment, a UPS is typically used to protect computers, data centers, telecommunication equipment or other electrical equipment where an unexpected power disruption could cause injuries, fatalities, serious business disruption and/or data loss. UPS units range in size from units designed to protect a single computer without a video monitor (around 200 VA rating) to large units powering entire data centers, buildings, or even cities
·       DC BATTERY  12v ,7.5AH  SMF (sealed maintenance free)
·       TRANSFORMER INVERTER SIDE (12-0-12, 500 va)
·       MOSFET IRF 540 N
·       MOSFET gate     :-max 6v
                             :-in this circuit 1.5v
·        MOSFET drain   :-12v dc  (max 100v,ID =33A)
·       MOSFET Source  :- gnd
·       CD4047                :-5v DC  (max 15v)
·       SCR 2P4N            :-12v cut off  
·       INDICATION      :-Battery low
                              :-Charging on
                              :-transformer short
·       RELAY                :-12v DC


The block diagram of the circuit advance mini UPS with charger unit as shown in figure. Normally, small power electronic gadgets utilize current less than 2A to enable the circuit and to charge the battery. It consists of power supply for electronic gadget, charger unit, switching unit, etc. The output power 500 watts delivered by the circuit UPS which is sufficient for most small powered gadget.

1.CD 4047

The CD 4047 B is capable of operating in either the mono stable or a stable mode. It requires an external capacitor (between pins 1 and 3) and an external resistor (between pins 2 and 3) to determine the output pulse width in the mono stable mode, and the output frequency in the a stable mode. A stable operation is enabled by a high level on the a stable input or low level on the as table input. The output frequency (at 50% duty cycle) at Q and Q outputs is determined by the timing components. A frequency twice that of Q is available at the Oscillator Output; a 50% duty cycle is not guaranteed.
®    Features
  1. v  Wide supply voltage range: 3.v to 15v
  2. v  High noise immunity: 0.45 VDD
  3. v  Low power TTL compatibility: Fan out of 2 driving 74L or 1 driving 74LS             

  1. v  Low power consumption: special CMOS oscillator configuration
  2. v  Mono stable (one-shot) or a stable (free-running) operation
  3. v True and complemented buffered outputs
  4. v  Only one external R and C required

v  Frequency discriminators
v  Timing circuits
v  Time-delay applications
v  Envelope detection
v  Frequency multiplication
v  Frequency division Ordering Code


Center Tapped transformer works in more or less the same way as a usual transformer. The difference lies in just the fact that its secondary winding is divided into two parts, so two individual voltages can be acquired across the two line ends.
The internal process is the same, which is when an alternating current is supplied to the primary winding of the transformer it creates a magnetic flux in the core, and when the secondary winding is brought near, an alternating magnetic flux is also induced in the secondary winding as the flux flows through the ferromagnetic iron core and changes its direction with each and every cycle of the alternating current. In this way an alternating current also flows through the two halves of the secondary winding of the transformer and flows to the external circuit.
                     When an additional wire is connected across the exact middle point of the secondary winding of a transformer, it is called a center tapped transformer. The wire is adjusted such that it falls in the exact middle point of the secondary winding and is thus at zero volts, forming the neutral point for the winding. This is called the “center tap” and this thing allows the transformer to provide two separate output voltages which are equal in magnitude, but opposite in polarity to each other. In this way, we can also use a number of turn ratios from such a transformer.
                       As it can be seen from the figure that this type of configurations gives us two phases through the two parts of the secondary coil, and a total of three wires, in which the middle one, the center tapped wire is the neutral one. So this center tapped configuration is also known as a two phase- three wire transformer system.

In this way, half the voltage appears across one half of the phase, that is from line 1 to neutral, and the other half of the voltage appears across the next phase, that is from neutral to Line 2. If the load is connected directly between line 1 and line 2, then we get the total voltage, that is, the sum of the two voltages. This way, we can get more amperes of current at the same voltage.
Working of this transformer

The two voltages, between line 1 and neutral and between neutral and line 2 can be named as VA and VB respectively. Then the mathematical relation of these two voltages shows that they are dependent upon the primary voltage as well as the turn ration of the transformer.
VA = (NA / NP) x VP

VB = (NB / NP) x VP

 One thing that should be noted here is that both the outputs VA and VB respectively are equal in magnitude but opposite in direction, which means that they are 180 degrees out of phase with each other. For this purpose, we also use a full wave rectifier with center tapped transformer, to make both the voltages in phase with each other.

Difference between a Normal and a Center Tapped Transformer

The primary difference that is evident here is that a normal transformer provides you with only one voltage, for example, say 240 V. But a center tapped transformer will provide you with two voltages each of 240/ 2 i.e. 120 V, so that we can drive two independent circuits.


BC 548,
 V CEO=65 V
                      The transistor terminals require a fixed DC voltage to operate in the desired region of its characteristic curves. This is known as the biasing. For amplification applications, the transistor is biased such that it is partly on for all input conditions. The input signal at base is amplified and taken at the emitter. BC 558 is used in common emitter configuration for amplifiers. The voltage divider is the commonly used biasing mode. For switching applications, transistor is biased so that it remains fully on if there is a signal at its base. In the absence of base signal, it gets completely off.
                       B J T s Bipolar transistors are composed of three segments called "Collector," "Base," and "Emitter." A thin insulating layer arises naturally between Base and Emitter. If a voltage of the correct polarity is applied to the Base and Emitter terminals, the insulating layer becomes so thin that it behaves as a conductor. If this voltage polarity is reversed, the insulating layer becomes wide. By changing the thickness of this insulating layer,the B J T behaves as a voltage-controlled valve or switch., whenever the Base-Emitter voltage is causing the insulator layer to become thinner, there also is a leakage current in the base terminal.This tiny current is proportional to any larger current passing through the entire transistor.Although the voltage between Base and Emitter controls the B J  T, designers usually ignore the base-emitter voltage, and the B J T is treated as a current-controlled valve or switch.     


                                 A diode is a specialized electronic component with two electrodes called the anode and the cathode. Most diodes are made with semiconductor materials such as silicon, germanium, or selenium. 
                                    The fundamental property of a diode is its tendency to conduct electric current in only one direction. When the cathode is negatively charged relative to the anode at a voltage greater than a certain minimum called forward break over, then current flows through the diode. If the cathode is positive with respect to the anode, is at the same voltage as the anode, or is negative by an amount less than the forward break over voltage, then the diode does not conduct current. This is a simplistic view, but is true for diodes operating as rectifiers, switches, and limiters. The forward break over voltage is approximately six tenths of a volt (0.6 V) for silicon devices, 0.3 V for germanium devices, and 1 V for selenium devices.
®          Features Diffused Junction
v  High Current Capability and Low Forward Voltage Drop
v  Surge Overload Rating to 30A Peak
v  Low Reverse Leakage Current
v  Lead Free Finish

®          Typical application 
v  For use in general purpose rectification of power supplies
v  Inverters
v  Converters and freewheeling diodes application.
v  These diodes are used to convert AC into DC these are used as half wave rectifier or full wave rectifier.
®          Applications
v  Switches
v  Voltage References
v  Bridge Rectifiers
v  Back EMF Protection


A relay is an electrically operated switch. Current flowing through the coil of the relay creates a magnetic field, which attracts a lever and changes the switch contacts. The coil current can be on or off so relays have two switch positions and they are double throw (changeover) switches.
                  The relay’s switch connections are usually labeled COM (POLE), NC and NO: COM/POLE= Common, NC and NO always connect to this; it is the moving part of the switch.NC = Normally Closed, COM/POLE is connected to this when the relay coil is not magnetized. NO = Normally Open, COM/POLE is connected to this when the relay coil is MAGNETIZED and vice versa.
A relay shown in the picture is an electromagnetic or mechanical relay.

                     There are 5 Pins in a relay. Two pins A and B are two ends of a coil that are kept inside the relay. The coil is wound on a small rod that gets magnetized whenever current passes through it.COM/POLE is always connected to NC (Normally connected) pin. As current is passed through the coil A, B, the pole gets connected to NO (Normally Open) pin of the relay

                         12 V DC- means that the voltage across the relay coil has to be 12V-DC. 50/60Hz- The relay can work under 50/60Hz AC. 5A,  240VAC- The maximum AC current and AC voltage specification that can be passed through NC, NO and pole pins/terminals of relay. 05VDC- It means that you need 5V to activate the relay. In other words, it means that the voltage across the relay coil has to be 5V-DC.

                  The MOSFET (Metal Oxide Semiconductor Field Effect Transistor) transistor is a semiconductor device which is widely used for switching and amplifying electronic signals in the electronic devices.   The MOSFET is a four terminal device with source(S), gate (G), drain (D) and body (B) terminals. The body of the MOSFET is frequently connected to the source terminal so making it a three terminal device like field effect transistor. The MOSFET is very far the most common transistor and can be used in both analog and digital circuits. The MOSFET works by electronically varying the width of a channel along which charge carriers flow.
®    The MOSFET can be function in two ways
1 Deflection Mode 
2 Enhancement Mode
®    Working Principle of MOSFET:

                  The aim of the MOSTFET is to be able to control the voltage and current flow between the source and drain. It works almost as a switch. The working of MOSFET depends upon the MOS capacitor. The MOS capacitor is the main part of MOSFET. The semiconductor surface at the below oxide layer which is located between source and drain terminal. It can be  inverted from p-type to n-type by applying a positive or negative gate voltages respectively.  When we apply the positive gate voltage the holes present under the oxide layer with a repulsive force and holes are pushed downward with the substrate. The deflection region populated by the bound negative charges which are associated with the accept or atoms. The electrons reach channel is formed. The positive voltage also attracts electrons from the n+ source and drain regions into the channel. Now, if a voltage is applied between the drain and source, the current flows freely between the source and drain and the gate voltage controls the electrons in the channel. Instead of positive voltage if we apply negative voltage, a hole channel will be formed under the oxide layer

v   Integrated circuits
v   Inverter
v  Chopper
v  Linear Voltage Regulators
v  Speed control of  dc motor 
v   Switch mode power supplies
v   Variable-frequency drives 
v   Power electronics applications
v   Sound reinforcement and home and automobile sound systems
v  MOSFETs in a switching power supply
v  MOSFETs in motor control applications

.   7. LED 
              A light-emitting diode (LED) 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 holes within the device, releasing energy in the form of photons. This effect is called electroluminescence.

®    Working principle

  A P-N junction can convert absorbed light energy into a proportional electric current. The same process is reversed here this phenomenon is generally called electroluminescence, which can be defined as the emission of light from a conductor under the influence of an electric field. The charge carriers recombine in a forward-biased P-N junction as the electrons cross from the N-region and recombine with the holes existing in the P-region. Free electrons are in the conduction band of energy levels, while holes are in the valence energy band. Thus the energy level of the holes will be lesser than the energy levels of the electrons. Some portion of the energy must be dissipated in order to recombine the electrons and the holes. This energy is emitted in the form of heat and light.
®     Applications

v  Indicators and signs
v  Lighting
v  Data communication and other signaling
v  Light sources for machine vision systems

  A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors may be used to reduce current flow, and, at the same time, may act to lower voltage levels within circuits. In electronic circuits, resistors are used to limit current flow, to adjust signal levels, bias active elements, and terminate transmission among other uses. High-power resistors, that can dissipate many watts of electrical power as heat, may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.
                        Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated circuits.
a)      Fixed resistor
b)      Variable resistors
®   Theory of operation                   


                       The behavior of an ideal resistor is dictated by the relationship specified by Ohm's law:
Ohm's law states that the voltage (V) across a resistor is proportional to the current (I), where the
constant of proportionality is the resistance (R). 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 flows through
that resistor.Practical resistors also have some inductance and capacitance which will also affect the
relation between voltage and current in alternating current circuits.

  A Zener diode allows current to flow from its anode to its cathode like a normal semiconductor diode, but it also permits current to flow in the reverse direction when its "Zener voltage" is reached. Zener diodes have a highly doped. Normal diodes will also break down with a reverse voltage but the voltage and sharpness of the knee are not as well defined as for a Zener diode.  Zener diodes are widely used in electronic equipment of all kinds and are one of the basic building blocks of electronic circuits. They are used to generate low power stabilized supply rails from a higher voltage and to provide reference voltages for circuits, especially stabilized power supplies. They are also used to protect circuits from over-voltage, especially electrostatic discharge .

 A conventional solid-state diode allows significant current if it is reverse-biased above its reverse breakdown voltage. When the reverse bias breakdown voltage is exceeded, a conventional diode is subject to high current due to avalanche breakdown. Unless this current is limited by circuitry, the diode may be permanently damaged due to overheating. A Zener diode exhibits almost the same properties, except the device is specially designed so as to have a reduced breakdown voltage, the so-called Zener voltage. By contrast with the conventional device, a reverse-biased Zener diode exhibits a controlled breakdown and allows the current to keep the voltage across the Zener diode close to the Zener breakdown voltage. For example, a diode with a Zener breakdown voltage of 3.2 V exhibits a voltage drop of very nearly 3.2 V across a wide range of reverse currents. The Zener diode is therefore ideal for applications such as the generation of a reference voltage  or as a voltage stabilizer for low-current applications.

®    Application of Zener Diode

  1. Zener Diode as Voltage Regulator
  2.  Waveform clipper
  3.  Voltage sifter
  4.   Overvoltage protection 

      10. BATTERY
 SMF (Sealed Maintenance Free) Battery measure created in an eco-friendly, ISO Certified & trendy plant with a huge producing capability and square measure being sold-out worldwide. There are differences between SMF batteries and other tubular batteries.  In SMF Batteries no distilled water or effort is needed and requires only a . There are a wide selection of SMF battery on the market to suit all applications of standby power needs like UPS, electrical converter and Emergency Lights, communication system, hearth Alarm & Security Systems, Railway communication, Electronic group action and money Registers, star Lanterns and Systems, etc. The SMF batteries are available industrial plant charged conditions and have a high period thereby requiring longer time intervals between recharging of batteries available. As we are one of the leading SMF battery manufacturers, we provide the genuine and products that tops in six stigmatic tests.

v  UPS
v  CAR
v  ICU


  A silicon controlled rectifier or semiconductor-controlled rectifier is a four-layer solid-state current-controlling device. The name "silicon controlled rectifier" is General Electric's trade name for a type of thyristor.
                     The silicon control rectifier (SCR) consists of four layers of semiconductors, which form NPNP or PNPN structures have three P-N junctions labeled J1, J2 and J3, and three terminals. The anode terminal of an SCR is connected to the p-type material of a PNPN structure, and the cathode terminal is connected to the n-type layer, while the gate of the SCR is connected to the p-type material nearest to the cathode.
                       An SCR consists of four layers of alternating p- and n-type semiconductor materials. Silicon is used as the intrinsic semiconductor, to which the proper dopants are added. The junctions are either diffused or alloyed. The doping of PNPN depends on the application of SCR, since its characteristics are similar to those of   the thyratron.

®   Modes of operation
  •      Forward blocking mode (off state)
  •       Forward conduction mode (on state)
  •       Reverse blocking mode (off state)
  •  Electric blanket,  electronic jar, various temperature control.
  •   Electric sewing machine, speed control of miniature type motor
  •   Light display equipment, lamp dimmer. Battery charger


                    In electrical engineering, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another.[1][2] The mechanism of a switch may be operated directly by a human operator to control a circuit (for example, a light switch or a keyboard button), may be operated by a moving object such as a door-operated switch, or may be operated by some sensing element for pressure, temperature or flow.

v  Biased switches
v  Rotary switch
v  Toggle switch
v  Mercury tilt switch
v  Knife switch
v  Footswitch
v  Reversing switch
v  Pushbutton switch
v  Selector switch
v  Joystick switch
v  Level actuator  limit witch
v  Proximate switch