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active mode and start to operate in reverse mode. The lack of symmetry is primarily due to the doping ratios of the emitter and the collector. The emitter is heavily doped, while the collector is lightly doped, allowing a large reverse bias voltage to be applied before the collector–base junction breaks down. The collector–base junction is reverse biased in normal operation. The reason the emitter is heavily doped is to increase the emitter injection efficiency: the ratio of carriers injected by the emitter to those injected by the base. For high current gain, most of the carriers injected into the emitter–base junction must come from the emitter.

Дайте відповіді на запитання.

1.What is a bipolar transistor?

2.Where does their name derive?

3.What are the main components of a BJT?

4.Why the BJT is not a symmetrical device?

5.Why the emitter is heavily doped?

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Варіант №5

5.1. Перепишіть речення та перекладіть рідною мовою. Визначте тип умовного речення.

5.1.1.We should not be able to demonstrate the flow of water in a pipe unless we installed a pump somewhere in the pump-line.

5.1.2.If you study the physics of semiconductors, you will know the properties of the p-n junction.

5.1.4.If the molecules of water had been divided into smaller parts it would not have been water any longer but some other substance.

5.1.5.They could have done it if they had obtained the necessary equipment.

5.2. Поставте дієслово у дужках в потрібному часі, зважаючи на тип умовного речення. Перекладіть речення рідною мовою.

5.2.1.If he (to use) this formula he would not have made this mistake.

5.2.2.If the North Star ceased to exist, the Earth (to continue) to receive light from it for about half a century.

5.2.3.Were the surface of the bearings harder the loss of the power to overcome the friction (to be) less.

5.2.4.If you (to be) here, you will help the trainees to do the laboratory work.

5.2.5.If you were to guarantee a regular supply of these goods, we (to be prepared) to conclude a new contract.

5.3. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на незалежний дієприкметниковий комплекс (The Absolute Participle Complex).

5.3.1.Steel being a very strong material, we find wide application of steel engineering.

5.3.2.The depth of the insert being sufficient it was possible to make a large number of regrinds.

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5.3.3.Whatever the arrangement, a constant voltage is applied, the value of the charging current being determined by the difference between the applied voltage and the voltage of the cell divided by the internal resistance of the cell.

5.3.4.Calculating machines are subdivided into 2 classes, analogue and digital, the basic distinction being the way in which numbers are represented inside the machine for purposes of calculating.

5.3.5.Current passes through the coil of wire, magnetic poles are produced at each end of the coil and it acts like a magnet.

5.4. Перепишіть речення, перекладіть речення англійською мовою, вживаючи незалежний дієприкметниковий комплекс

(The Absolute Participle Complex).

5.4.1. Коли заняття закінчились, студенти пішли додому.

5.4.2. Електричні пристрої використовують повсякденно, холодильник-один з них..

5.4.3. Професор закінчив експеримент вчасно тому, що йому допомогли студенти.

5.5. Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на об’єктний інфінітивний комплекс

(Complex Object).

5.5.1.He wishes the work to be done in time.

5.5.2.The workers expected the nuts to be delivered by the end of the working day.

5.5.3.I find him to be a very sophisticated worker.

5.5.4.Do you expect the contract to be signed soon?.

5.5.5.The manager ordered the cargo to be insured.

Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на суб’єктний інфінітивний комплекс (Complex Subject).Перекладіть англійською мовою.

5.6.1.The geographical demand for transport was unlikely to alter

much.

5.6.2.The vessel is reported to have arrived in Odessa.

5.6.3.The laser beam seems to have almost unlimited industrial possibilities.

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5.6.4.Mechanical locks and relays are assumed to be replaced by electronic units, such as transistors, semiconductor diodes and ferrite cores in a new signaling system.

5.6.5.This new approach to the problem discussed turns out to be the most satisfactory.

5.7.Перекладіть англійською, вживаючи об’єктний інфінітивний комплекс (Complex Object) та суб’єктний інфінітивний комплекс (Complex Subject).

5.7.1.Кажуть, що станок має 2 різака.

5.7.2.Здається, вони не помили лобове скло.

5.7.3.Я хочу, щоб ви мені допомогли.

5.7.4.Вона сподівається, що дитина отримає диплом.

5.7.5.Ми примусили його працювати.

5.8.Перепишіть текст за фахом та перекладіть його рідною мовою.

5.8.1. Електротехнічний факультет

POWER STATIONS

A power station is an industrial facility for the generation of electric power. At the center of nearly all power stations is a generator, a rotating machine that converts mechanical energy into electrical energy by creating relative motion between a magnetic field and a conductor. The energy source harnessed to turn the generator varies widely. It depends chiefly on which fuels are easily available and on the types of technology that the power company has access to.

In thermal power stations, mechanical power is produced by a heat engine that transforms thermal energy, often from combustion of a fuel, into rotational energy. Most thermal power stations produce steam, and these are sometimes called steam power stations. Not all thermal energy can be transformed into mechanical power, according to the second law of thermodynamics. Therefore, there is always heat lost to the environment. The efficiency of a steam turbine is limited by the maximum temperature of the steam produced and is not directly a function of the fuel used. For the same steam conditions,

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coal, nuclear and gas power plants all have the same theoretical efficiency.

Thermal power plants are classified by the type of fuel and the type of prime mover installed. Nuclear power plants use a nuclear reactor's heat to operate a steam turbine generator. Fossil fuelled power plants may also use a steam turbine generator or in the case of natural gas fired plants may use a combustion turbine. Solar thermal electric plants use sunlight to boil water, which turns the generator. Steam turbine plants use the dynamic pressure generated by expanding steam to turn the blades of a turbine. Almost all large nonhydro plants use this system. About 80% of all electric power produced in the world is by use of steam turbines. Gas turbine plants use the dynamic pressure from flowing gases (air and combustion products) to directly operate the turbine. Natural-gas fuelled (and oil fueled) combustion turbine plants can start rapidly and so are used to supply "peak" energy during periods of high demand, though at higher cost than base-loaded plants.

Дайте відповіді на запитання.

1.What is the main purpose of power plants?

2.What is the driving part of a power plant?

3.What does the energy source depend on?

4.What do thermal stations produce?

5.How are they classified?

5.8.2. Інженерно-фізичний факультет

THE CUPOLA FURNACE

A Cupola is a melting device used in foundries that can be used to melt cast iron, ni-resist iron and some bronzes. The cupola can be made almost any practical size. The overall shape is cylindrical and the equipment is arranged vertically, usually supported by four legs. The overall look is similar to a large smokestack.

The bottom of the cylinder is fitted with doors which swing down and out to 'drop bottom'. The top where gases escape can be open or fitted with a cap to prevent rain from entering the cupola. To

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control emissions a cupola may be fitted with a cap that is designed to pull the gases into a device to cool the gasses and remove particulate matter. The shell of the cupola, being usually made of steel, has refractory brick and refractory patching material lining it. The bottom is lined in a similar manner but often a clay and sand mixture ("bod") may be used, as this lining is temporary. Some cupolas are fitted with cooling jackets to keep the sides cool and with oxygen injection to make the coke fire burn hotter.

To begin a production run, called a 'cupola campaign', the furnace is filled with layers of coke and ignited with torches. Some smaller cupolas may be ignited with wood to start the coke burning. When the coke is ignited, air is introduced to the coke bed through ports in the sides called tuyeres. When the coke is very hot, solid pieces of metal are charged into the furnace through an opening in the top. The metal is alternated with additional layers of fresh coke. Limestone is added to act as a flux. As the heat rises within the stack the metal is melted. The operator of the cupola, the 'cupola tender', observes the amount of iron rising in the well of the cupola. When the metal level is sufficiently high, the cupola tender opens the taphole to let the metal flow into a ladle or other container to hold the molten metal. When enough metal is drawn off the taphole is plugged with a refractory plug made of clay.

After the cupola has produced enough metal to supply the foundry with its needs, the bottom is opened, or 'dropped' and the remaining materials fall to the floor between the legs. This material is allowed to cool and subsequently removed. The cupola can be used over and over. A 'campaign' may last a few hours, a day, weeks or even months.

Дайте відповіді на запитання.

1.How is the Cupola arranged?

2.Why is the top fitted with a cap?

3.Why should the material used in construction be refractory?

4.How can we begin a cupola campaign?

5.What is the task of the operator?

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5.8.3. Машинобудівний факультет

CRANES

A crane is a lifting machine, generally equipped with a winder (also called a wire rope drum), wire ropes or chains and sheaves, that can be used both to lift and lower materials and to move them horizontally. Cranes are commonly employed in the transport industry for the loading and unloading of freight, in the construction industry for the movement of materials and in the manufacturing industry for the assembling of heavy equipment. The first construction cranes were invented by the Ancient Greeks and were powered by men or beasts of burden, such as donkeys The earliest cranes were constructed from wood, but cast iron and steel took over with the coming of the Industrial Revolution. Modern cranes usually use internal combustion engines or electric motors and hydraulic systems to provide a much greater lifting capability than was previously possible, although manual cranes are still utilised where the provision of power would be uneconomic.

Cranes exist in an enormous variety of forms – each tailored to a specific use. Sizes range from the smallest jib cranes, used inside workshops, to the tallest tower cranes, used for constructing high buildings. For a while, mini - cranes are also used for constructing high buildings, in order to facilitate constructions by reaching tight spaces. Finally, we can find larger floating cranes, generally used to build oil rigs and salvage sunken ships. There are two major considerations in the design of cranes. The first is that the crane must be able to lift a load of a specified weight and the second is that the crane must remain stable and not topple over when the load is lifted and moved to another location.

A balance crane contains a horizontal beam (the lever) pivoted about a point called the fulcrum. The principle of the lever allows a heavy load attached to the shorter end of the beam to be lifted by a smaller force applied in the opposite direction to the longer end of the beam. The ratio of the load's weight to the applied

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force is equal to the ratio of the lengths of the longer arm and the shorter arm, and is called the mechanical advantage.

A jib crane contains a tilted strut (the jib) that supports a fixed pulley block. Cables are wrapped multiple times round the fixed block and round another block attached to the load. When the free end of the cable is pulled by hand or by a winding machine, the pulley system delivers a force to the load that is equal to the applied force multiplied by the number of lengths of cable passing between the two blocks. This number is the mechanical advantage.

Дайте відповіді на запитання.

1.What are the main crane components?

2.Who first introduced them?

3.How many forms of cranes are there?

4.What are the two main considerations in the crane design?

5.What is a mechanical advantage?

5.8.4. Транспортний факультет

A CARBURATOR

A carburetor is a device that blends air and fuel for an internal combustion engine. It was invented by Karl Benz before 1885 and patented in 1886. The carburetor works on Bernoulli's principle: the faster air moves, the lower its static pressure, and the higher its dynamic pressure. The throttle (accelerator) linkage does not directly control the flow of liquid fuel. Instead, it actuates carburetor mechanisms which meter the flow of air being pulled into the engine. The speed of this flow, and therefore its pressure, determines the amount of fuel drawn into the airstream.

A carburetor basically consists of an open pipe, a "throat" or "barrel" through which the air passes into the inlet manifold of the engine. The pipe is in the form of a venturi: it narrows in section and then widens again, causing the airflow to increase in speed in the narrowest part. Below the venturi is a butterfly valve called the throttle valve — a rotating disc that can be turned end-on to the airflow, so as to hardly restrict the flow at all, or can be rotated so that it (almost) completely blocks the flow of air. This valve controls

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the flow of air through the carburetor throat and thus the quantity of air/fuel mixture the system will deliver, thereby regulating engine power and speed. The throttle is connected, usually through a cable or a mechanical linkage of rods and joints or rarely by pneumatic link, to the accelerator pedal on a car or the equivalent control on other vehicles or equipment.

Fuel is introduced into the air stream through small holes at the narrowest part of the venturi and at other places where pressure will be lowered when not running on full throttle. Fuel flow is adjusted by means of precisely-calibrated orifices, referred to as jets, in the fuel path.

To ensure a ready mixture, the carburetor has a "float chamber" (or "bowl") that contains a quantity of fuel at nearatmospheric pressure, ready for use. This reservoir is constantly replenished with fuel supplied by a fuel pump. The correct fuel level in the bowl is maintained by means of a float controlling an inlet valve, in a manner very similar to that employed in a cistern (e.g. a toilet tank). As fuel is used up, the float drops, opening the inlet valve and admitting fuel. As the fuel level rises, the float rises and closes the inlet valve. Floats can be made of different materials, such as sheet brass soldered into a hollow shape, or of plastic; hollow floats can spring small leaks and plastic floats can eventually become porous and lose their flotation; in either case the float will fail to float, fuel level will be too high, and the engine will not run unless the float is replaced. As the fuel evaporates from the float bowl, it leaves sediment, residue, and varnishes behind, which clog the passages and can interfere with the float operation.

Дайте відповіді на запитання.

1.In which kind of engines are carburetors used?

2.What is Bernoulli`s principle?

3.What does a carburetor consist of?

4.How is fuel introduced?

5.What does a float chamber serve for?

5.8.5. Факультет інформаціонно-обчислювальної техніки

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THE INTERNET

The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks of local to global scope that are linked by a broad array of electronic and optical networking technologies. The Internet carries a vast array of information resources and services, most notably the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support electronic mail.

The origins of the Internet reach back to the 1960s when the United States funded research projects of its military agencies to build robust, fault-tolerant and distributed computer networks. This research and a period of civilian funding of a new U.S. backbone by the National Science Foundation spawned worldwide participation in the development of new networking technologies and led to the commercialization of an international network in the mid 1990s, and resulted in the following popularization of countless applications in virtually every aspect of modern human life.

The Internet has no centralized governance in either technological implementation or policies for access and usage; each constituent network sets its own standards.

The complex communications infrastructure of the Internet consists of its hardware components and a system of software layers that control various aspects of the architecture. While the hardware can often be used to support other software systems, it is the design and the rigorous standardization process of the software architecture that characterizes the Internet and provides the foundation for its scalability and success. The Internet Standards describe a framework known as the Internet Protocol Suite.

The Internet Layer enables computers to identify and locate each other via Internet Protocol addresses, and allows them to connect to one-another via intermediate networks. Lastly, at the bottom of the architecture, is a software layer, the Link Layer, that

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