задание по англ. языку

Circuits and components

A. Simple circuits

‘The circuit diagrams below show lamps connected in a parallel circuit and in a series circuit. The supply has live and neutral conductors. On an alternating current (AC) supply, the difference between live and neutral is that conductors on the neutral side of appliances are earthed - that is, connected to earth (the ground).

B.  Mains AC circuits and switehboards

Where an AC supply enters a building, it is connected to a switchboard. This has a number of switches to allow different circuits in the building to be switched on and off. Circuits include power circuits. These supply the power sockets (or sockets) for the plugs on appliances. Usually, a circuit-breaker is fitted to each circuit, This is a safety switch that switches off automatically if there is a problem. This may happen if a person touches a live conductor, or if there is a short circuit. A short circuit is when current flows directly from a live conductor to @ neutral conductor ~ for example,
due to damaged insulation. Circuit breakers also allow circuits to be switched off manually, to isolate them (switch them off safely) - for example, before maintenance work.

Note: The equipment in switchboards is often called switchgear.

3) учебник И. В. Орловской, стр. 318-319, § 31,

страница 171, упражнение 1 B; страница 172, упражнение 1С;

4) учебник И. В. Орловской, стр. 320, § 32, 33, 34, 35,

страница 214, упражнение 1; стр. 215, упражнение 3, 4 B, C;

C. Printed and integrated circuits

The circuits in electrical appliances are often printed circuits, on printed circuit boards (PCBs). These are populated with (fitted with) electrical components, Many appliances also contain small, complex integrated circuits - often called microchips (or chips) - made from silicon wafers (very thin pieces of silicon). They act as semiconductors, which can be positively charged at certain points on their surface and negatively charged at other points.

This principle is used to make very small circuits.

D. Electrical and electronic components
There are many types of electrical and electronic components, These can be used individually or combined with other components to perform different tasks. For example:

•  Sensors or detectors can sense or detect levels of —or changes in ~ values such as temperature, pressure and light,
• Control systems use feedback from sensors to control devices automatically. For example, mechanical devices such as water valves may be moved or adjusted by servomechanisms — electrically powered mechanisms that are controlled automatically by signals (‘messages’) from sensors.
• Logic gates are widely used in control systems. They send signals, in the form of low voltages, to other devices. An output signal from the logic gate is switched on or off, depending on the input signals it receives.

Notes: The term electronic, rather than electrical, generally describes small but often very comy
circuit and components that operate at a low voltage.

45.1 Make word combinations with circuit using words from A and B opposite. Then match the combinations with the descriptions (1-6) below.

a __________

a __________

a __________

a __________                     circuit

a __________

an __________

1 a circuit containing one or more sockets
2 a simple circuit where all the components are placed one after the other along the same conductor
3 a microchip ~ a very small, often complex circuit
4 what happens if live and neutral conductors touch while a current is flowing, and there is no component or appliance between them
5 a circuit which allows different components to be controlled independently by separate switches
6 a circuit that can be populated with a large number of components

45.2 Complete the task from an engineering textbook. Sometimes more than one word is possible.
Look at B and C opposite and Appendix XIII on page 118 to help you.

In an experiment, the lights in a room are connected to two types of electronic (1) _________.   The first is an occupancy sensor, which will (2)_________  the movement of a person entering the room, and the second is some kind of photosensor, which can determine whether it’s daylight or dark. These two devices are connected to an AND gate - a (3) _________ _________  that will produce an output current only if it receives two input currents - in this case, from both the occupancy sensor and the photosensor.
Therefore, a (4) _________ will be sent to the Light switch to (5) _________ the lights only if a person enters the room and if it’s dark.

However, for this system to work, we are assuming that the type of photosensor used will be ‘one which is designed to produce a current in the dark, and which will then (6) _________ as soon as daylight appears. But such a sensor may be designed to work in the opposite way - producing a current when it detects daylight and no current in the dark.
This would cause an obvious problem. In this case, what type of logic gate could be placed between the photosensor and the AND gate in order to solve the problem?

45.3 Can you answer the question in the text in 45.2? Look at Appendix XIII on page 118 to help you.

- A printed circuit board

- An integrated circuit on a microchip

Energy 

A. Forms of energy

The effects of energy can be seen, felt or heard in different ways, depending on the form of energy in question. The main forms are listed below:

• kinetic energy: energy in the form of movement ~ a type of mechanical energy 
• thermal energy: energy in the form of heat
• clectrical energy: the energy of an electric current
• sound energy: energy in the form of noise
• light energy: for example, light emitted from the sun or from a light bulb
• chemical energy: energy within substances that can produce a chemical reaction
• nuclear energy: energy from an atomic reaction.

Energy cannot be created or destroyed, only converted from one form to another, For example, in a torch powered by batteries, chemical energy stored in the battcries is converted to electrical energy, and the electrical energy is converted to light energy.

Mechanical energy can be stored as potential energy. An example is a load, lifted by a crane and suspended at a high level. The weight has the potential (in the future) to be released and allowed to fall, becoming kinetic energy. Energy can also be stored when a component is elastically deformed. This is called strain energy. An example is the spring in a watch, which is wound up, then progressively unwinds.

Note: For more on deformation, see Unit 18, For more on strain, see Unit 30.

B. Energy efficiency 

Machines often convert an energy source, such as electricity, to another form of useful energy ~ in other words, energy used for a purpose. For example, a motor converts electrical energy (the energy source) into kinetic energy (useful energy). Bur it also converts some energy into heat and noise.

As this will be dissipated into the air, and not used, it is waste energy.

If a machine converts a high percentage of energy into useful energy, it is efficient. For example, if a motor converts 75% of the electrical energy it consumes into kinetic energy, and wastes 25% as thermal and sound energy, it is seventy-five percent efficient. Improving efficiency - making efficiency gains — is a key focus in engineering.

C. Work and power

The amount of energy needed to do a task ~ for example, lifting 2 load to a certain height by crane ~ is called work, The amount of energy converted in order to perform tasks ~ in other words, the amount of work done — is measured in joules ()). If a force of one newton is required to keep an object moving, the work required to move that object over a distance of one metre is equal to one joule,

The speed, or rate, at which work is done is called power, and is measured in watts (W). One watt is one joule per second. Power, in watts, is often referred to as wattage. A powerful motor will have a higher wattage than a less powerful one.

35.1 Make word combinations with energy using words from A and B opposite. Then match the combinations with the descriptions (1-8).

1. _______________________ energy = energy stored within the liquids or solids in a bartery
2. _______________________ energy = mechanical energy in the form of movement

3. _______________________ energy = potential energy stored in a deformed material
4. _______________________ energy = energy converted to the form required for a purpose
5. _______________________ energy = energy converted to a form that cannot be used
6. _______________________ energy = the form of energy that shines, and can be seen

7. _______________________ energy = the form of energy that can be heard
8. _______________________ emergy that results in an increase in temperature