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Working and Applications of Common Collector Amplifier

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An amplifier is an electronic circuit that is used to amplify the voltage signal or a current signal. The amplifier circuits are generally designed with one or more transistors. A BJT or a FET transistor is a major component of the amplifier system. They can be categorized into a weak signal amplifier or a power signal amplifier and are used in wireless communication and broadcasting, and audio equipment. This article discusses the common collector amplifier which is the amplifier topologies.

Common Collector Amplifier

The common collector amplifier is one of the three basic BJT amplifier topologies. In this circuit, the base of the transistor serves as an input, emitter as the output and the collector is grounded that is, common for both emitter and base. It is also called as an emitter follower. This configuration acts as a buffer. This circuit provides offer low output impedance while taking high input impedance. This configuration is mainly used in digital circuits with logic gates and has many applications.

Common Collector Configuration

Common Collector Configuration

Characteristics of Common Collector Amplifier

The load resistor in the common collector amplifier being placed in series with the emitter circuit receives both the base current and collector currents.

Since the emitter of a transistor is the sum of the base and collector currents, since the base and collector currents always add together to form the emitter current, it would be reasonable to assume that this amplifier will have a very large current gain.

The common collector amplifier has quite a large current gain, larger than any other transistor amplifier configuration. The characteristics of the common collector amplifier as mentioned below.

ParameterCharacteristics 
Voltage gainZero
Current gainHigh
Power gainMedium
Input or output phase relationshipZero degree
Input resistanceHigh
Output resistanceLow

Input Characteristics

The common collector characteristics are quite different from the common base and common emitter characteristics. This is because the input voltage Vbc is largely determined by the output voltage Vec. As Vbc increases with Vec constant Veb decreases hence Ib decreases.

Input Characteristics of Common Collector

Input Characteristics of Common Collector

Output Characteristics

Here as Vcc increases Ie also increases. Just as in common emitter output characteristics Ic increases with increasing Ib, so Ie also increases here with the increase in Ib. Hence, for constant Vec, Ie increases with Ib.

Output Characteristics of Common Collector

Output Characteristics of Common Collector

The small signal circuit performance can now be calculated. Total circuit performance is the sum of quiescent and small signal performance. The AC model circuit is shown below.

AC Modeling of Common Collector Amplifier

AC Modeling of Common Collector Amplifier

Current Gain

The current gain is defined as the ratio of the load current to the input current.

Ai= il/ib= -ie/ib

From the h-parameter circuit, it can be determined that the emitter and base currents are related to the dependent current source by the constant hfe+1. The current gain is dependent only on the BJT characteristics and independent of any other circuit element values. Its value is given by

Ai= hfe+1

Input Resistance

The input resistance is given by

This result is identical to that for a common emitter amplifier with an emitter resistor. The input resistance to a common collector amplifier is large for typical values of the load resistance Re.

Voltage Gain

The voltage gain is the ratio of output voltage to input voltage. If the input voltage is again taken to be the voltage at the input to the transistor, Vb.

Av= Vo/Vb
Av= (vo/il)(il/ib)(ib/vb)

Replacing each term with its equivalent expression

Av= (Re)(Ai)(1/Ri

The above equation is somewhat less than unity. The approximation equation of voltage gain is given by

The overall voltage gain can be defined as

Avs= Vo/Vs

This ratio can be directly derived from the voltage gain Av, and a voltage division between the source resistance Rs and the amplifier input resistance R.

After substitutions of appropriate equations, the overall voltage gain is given by

Avs= 1- (hie+Rb) / (Ri+Rb)

Output Resistance

The output resistance is defined as the Thevenin resistance at the output of the amplifier looking back into the amplifier. The circuit is shown below, the AC equivalent circuit to calculate the output resistance.

Common Collector Output Resistance AC Equivalent Circuit

Common Collector Output Resistance AC Equivalent Circuit

If a voltage v is applied to the output terminals, the base current is found to be

ib= -v/(Rb+hie)

The total current flowing into the BJT is given by

i= -ib – hfe . ib

The output resistance is calculated as

Ro= v/i = (Rb+hie) / (hfe+1)

The output resistance for a common collector transistor amplifier is typically small.

Applications

  • It is useful as an impedance matching device since its input impedance is much higher than its output impedance.
  • It is used in digital circuits with logic gates.
  • It is used as a switching circuit.
  • It is also used for cascade amplifier circuit isolation.

This article discusses the working of the common emitter amplifier circuit and its applications. By reading the above information you have got an idea about this concept. Furthermore, any queries regarding this article or if you want to implement Electrical and Electronic projects please feel free to comment in the below section.

How to Build A Voltage Inverter Circuit, Working and Its Applications?

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Voltage Inverter Device

Voltage Inverter Device

Generally, many people have confused on voltage inverter and converter, and their working principles. An inverter is an electrical device, which converts DC power to AC power and either increases or decreases the voltage level accordingly. In comparison, a converter changes the voltage level but does not change its type. So in converters, an AC voltage would still be AC and a DC voltage would still be in DC. Inverters are becoming more popular along with along with solar power systems where we get a low voltage DC supply to power ordinary appliances that either run on 110V or 220V AC.

Inverters are used in a large number of electrical power applications. Voltage inverters are divided into three categories, Pulse-width Modulated Inverters, Square-wave Inverters, and Single-phase Inverters with Voltage Cancellation.

Voltage Inverter Working Principle?

The basic idea behind every inverter circuit is to produce oscillations using the given DC and apply these oscillations across the primary of the transformer by amplifying the current. This primary voltage is then stepped up to a higher voltage depending upon the number of turns in primary and secondary coils.

Most inverters are of the variable voltage, variable frequency design. They consist of a converter section, a bus capacitor section and an inverting section. The converter section uses semiconductor devices to rectify (convert) the incoming fixed voltage, fixed frequency 3-phase AC power to DC voltage which is stored in the bus capacitor bank.

There it becomes a steady source of current for the power devices which are located in what is known as the inverting section. The inverting section absorbs power from the DC bus cap bank, inverts it back to simulated 3-Phase AC sine waves of varying voltage and varying frequency that are typically used to vary the speed of a 3-phase induction motor.

Voltage Inverter

Voltage Inverter

Steps to Make a Voltage Inverter Circuit

The different steps to make a voltage inverter includes the following

Required Components

  • Breadboard to place all the components and to solder everything on
  • LM555IC chip is the heart of the circuit
  • The values of Resistors, capacitors, and diodes are shown in the circuit below.
  • Color LEDs and voltage supply

Add the IC LM555 Chip

  • Place the LM555IC chip on the breadboard which is the heart of the entire circuit
  • Give the voltage supply and GND
  • Connect the two pins from Pin 6 to Pin 2 and connect the two resistors R1, R2
  • Add a Capacitor C1
  • Watch out of the Positive and the Negative connections of the capacitor
  • The LED has two terminals namely positive and negative, where a shorter leg is the negative terminal
IC LM555 Chip Pulse Generator

IC LM555 Chip Pulse Generator

Design the Circuit by Connecting the Components

The voltage inverter circuit is shown below, that uses a well known LM555IC timer chip. The schematic diagram divided into three parts, namely an oscillator, rectifier, and voltage regulator.An oscillator is used to convert DC into AC, a special type of rectifier is used to convert AC to DC and finally a voltage regulator.

Voltage Inverter Circuit

Voltage Inverter Circuit

An oscillator is used to convert DC into AC, a special type of rectifier is used to convert AC to DC and finally a voltage regulator.

This IC in the above circuit is wired as an oscillator. The high period of the of the cycle acquires 0.6933× (R1+R2) ×C1 Secs and the low period acquires 0.693×R2×C1 Sec.With the R1, R2 and C1 values, this generates a square wave approximately 1.3 kHz at pin-3.

The connection of the two diodes provides rectification and certainly, they do generate a DC signal, but in a dissimilar way than the general diode bridges.

When pin-3 of the IC is high, the D1 diode ON and conducts and thus the IC charges C2 capacitor. When pin-3 toggles low, the diode D1 OFF and it blocks current.

There will be a charge of C2 capacitor and the positive side of the capacitor is now the 0V level. The other side must then be -VCC if we neglect the threshold of D1 diode for a while.

That means that diode D2 performs and capacitor C2 charges, C3 with a -Ve voltage. And capacitor C3 works as a smoothing capacitor.

That means that diode D2 performs and capacitor C2 charges, C3 with a -Ve voltage. And capacitor C3 works as a smoothing capacitor.

As said, the o/p stress must be controllable. The best way to do is to make a changeable voltage divider with one variable resistor and a fixed resistor. This is the merge of R3 & Q1 here, Q1 is a P-channel junction field effect transistor.

Before turning up this circuit, you can try to use the voltage control as Vcc, and go down R3 and Q1.Though, the H0420 design, the pin of the LC-driving voltage couldn’t produce an ample current to feed the IC chip.

In addition, this IC requires a power supply of 4.5V. There are other implementations of the IC. A low-power CMOS version of the chip would obey the power supply of the LC-driving voltage pin of the H0420. low-power CMOS version of the chip would obey the power supply of the LC-driving voltage pin of the H0420.

Applications of voltage inverter

Inverters are a practical device and are a useful piece of equipment for many different applications. Anyone who wants to run a laptop or other electronic device within a car or RV an inverter is required.

Different inverters may have different features making them better suited for different specific applications. Very small inverters are available that connect to a car cigarette lighter, with a single three-prong AC outlet as the output.

Large inverters are generally designed to be hardwired into a building electrical system. Some inverters offer 240 volts output.

Inverter types can be categorized by output waveform, switch type, switching technology and frequency.

Thus, this is all about steps to make a voltage inverter circuit. Furthermore, any queries regarding this concept or electrical and electronics projects, please give your valuable suggestions by commenting in the comment section below. Here is a question for you, what is the main function of an inverter?

Heart Attack Detection and Medical Attention Using Heart Beat Sensor

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Heartbeat sensor for medical applicationsHeart attack (coronary artery disease) is one of the most common and very serious effects of aging. The cholesterol, fatty deposits, emotional stress, and drug intake lead to build spasm in blood vessel walls. As the spasm grows, less blood can flow through the arteries. As a result, the heart muscle can’t get the blood or oxygen what exactly, it needs. This can lead to a heart attack. In this article, We are developing a system which will help to decrease the death rate due to the heart attack by early heart attack detection. In our system, we will be using smart Heart Beat sensor which is easily available in the market.

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Accurate Room Temperature Controller Using 8051 Microcontroller

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Room Temperature Controller

Room Temperature Controller

Temperature control is a procedure to maintain the temperature at a certain level. This method is commonly used in all regions of the world. Recently in the globalization period, this method becomes an important part because there are several applications in daily life includes this procedure especially server room and greenhouse. Every day server room works nonstop in 24 hours. During this procedure, server room needs to be checked frequently in order to confirm its functionality and efficiency, particularly on temperature. Accurate room temperature controller mentioned as the best technique in any application by controlling the temperature automatically.

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Remote Controlled Hovercraft Using Android Application

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Hovercraft

Hovercraft

The first practical design of the hovercraft was resulting from British invention from 1950 to 1960. The RC Hovercraft are used throughout the world as a specialized transport in disaster relief, coast guard, military, and in passenger service. These vehicles are supported in various ways, some of them are specially designed wings. The hovercraft is a vehicle that can drive like a car, flies like a plane, it can move on the water & land surface and float like a boat. Hovercrafts are the hybrid vehicles operated by a pilot. In this, we will discuss RC Hovercraft by an android.

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GSM based Programmable Energy Meter with Bill Estimation Display to The User

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GSM based Programmable Energy Meter with Bill Estimation Display to The User

GSM based Programmable Energy Meter

Electricity is an essential requirement for leading a happy life. It is to be correctly used and achieved. Many statistical errors overcome in the process of monthly customer billing. This idea of wireless data transmission is being planned to decrease the human involvement to gather the monthly reading and to minimize the technical problems about the billing process. This will help in a huge reduction of power thefts as well to analyze average power consumption of a certain locality. An automatic meter reading system is an actual way of data collection, that permit substantial saving through the saving of meter read, more accuracy, allow regular reading, better billing, condensed tempering. It gives better customer services, by transferring alert of power cuts and updates. Automatic meter reading (AMR) technology is used for remote monitoring, control domestic energy meter and also to reduce the power thievery. This article presents a programmable energy meter using GSM technology, that enables energy Supplier companies to read the energy meter reading frequently without the person visiting each house. This project is very beneficial for small villages or remote area. This system can be very efficient, swift and accurate.

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Fingerprint Recognition Based Biometric Voting Machine

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Biometric Voting Machine

Biometric Voting Machine

The biometric is a technology of measuring, science and it analyze the biological data. In the modern communications approximately it has accessible electronically,   users of computer technology, it has increment in electronic services and with the security system. It improves in the election system with the help of new technologies in voting process. The information about election data is stored, recorded and processed the above information as a digital information. In olden days the information security is with the help of military and instructions of the government. The human body characteristic like DNA, fingerprints, voice patterns and hand measurements is used for authentication purpose. The e-services and information security are making sure that data, communication, have the security and privacy enable.

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Controlling of Electricity Theft Using Smart Prepaid Energy Meter

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Electricity Theft Control using Smart Card

Electricity Theft Control using Smart Card

The electricity theft has appeared as a major problem in power divisions in particular in the expanding countries. A vast amount of income is lost due to this theft. In some nations this is so strict that governments are acquiring losses instead of income. In some cases government has to supply subsidies to the power division to keep a reasonable price of power. The economic loss results in lack of funds for savings to develop the existing capacity of electricity.

As a result government has not succeeded to assure the ever rising demand of electricity. Robbery electricity, avoiding a meter, billing wrongdoings and not paid bills. Billing irregularity comprises wrong meter reading taken by bribed service man. Different technical and non technical techniques were projected in the past to notice electricity stealing. Some of the technical methods to identify pilferage are utilize of central observer meter on harmonic generator, secondary terminals of distribution transformer, extreme learning machine, genetic support vector machines & a power line impedance technique.

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Dual Tone Multi Frequency Based Load Control System

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DTMF based Load Control System

DTMF based Load Control System

In general, controlling of the home appliances can be done by normal switches. But, these days we frequently see the home automation for controlling the appliances using several technologies. This article presents the DTMF based load control system. DTMF is a signaling system for recognizing the inputs on a keypad. It is used in signaling for telecommunication over analog telephone lines in the voice frequency band among telephone handsets and communication devices. This Article discusses about DTMF based load control system.

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Biosensors – Types, How Does it Works and Applications

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Bio Sensor

Bio Sensor

The Biosensor is used to detect the analyte so the Biosensor is an analytical device and it gathers the biological components with a Physicochemical detector. The sensing biological elements are biometric components interact with the recognize and analyze the study and the components like tissue, microorganisms, antibodies, nucleic acids and etc. The sensitive elements of biological can also generate by the biological engineering. The detector elements transform the signals from the interface of analyte with the biochemical elements into other signals like transducer and it can be measured more easily and qualified. The Biosensor devices are associated with the electronics and the signal processors and they are generally responsible for the display of the results and they are user-friendly. The Biosensor research has a significant role in the development of modern electronics. This article discusses about different types of Biosensors working and applications.

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