Вправа 3. Прочитайте слова за викладачем. High, design, farther, fasten, series; influence, illustrate, calibrate, delicate, ultimate, consequently

High, design, farther, fasten, series; influence, illustrate, calibrate, delicate, ultimate, consequently, primarily; diameter, microammeter, galvanometer, equilibrium, fundamentally, sufficiently.

Вправа 4. Дайте відповіді на питання до тексту.

1. What is responsible the action of almost all the types of measuring instru­ments for?

2. What is a voltmeter?

3. Should voltmeters and ammeters be classed together? Why?

4. How is ammeter connected in the circuit?

5. How is voltmeter connected in the circuit?

6. How is ammeter or voltmeter connected to a circuit to measure electric current or potential difference?

Вправа5. Знайдіть інфінітиви дієслів в тексті та проаналізуйте їх функцію.

Вправа 6. Перекладіть слова з тексту на українську та запам’ятайте їх.

By this is meant, consequently, whenever, hence, on the other hand; merely; therefore; accordingly; that is; however.

Вправа 7. Знайдіть українські еквіваленти серед поданих англійських словосполучень.

Measuring instru­ments; is primarily responsible for; exceedingly important influence; fundamentally current-measuring devices; to measure small values of current; should be classed together.; which are connected in series; only a small drop of voltage in the circuit; sufficiently high; and the power absorbed from the circuit; а coil of fine copper wire; a fixed scale; to prevent a change in the electric current; for which a measurement of the potential difference is required.

досить високий; надзвичайно важливий вплив; для вимірювання малих значень струму; вимірювальні прилади; які з’єднані послідовно; в першу чергу відповідає за; принципово струмо-вимірювальні прилади; споживана потужність від мережі; повинні класифікуватися разом; лише невелике падіння напруги в ланцюзі; котушка з тонкого мідного дроту; фіксована шкала; щоб запобігти зміні електричного струму; для якої потребують вимірювання різності потенціалів.

Вправа 8. Опишіть принципи роботи

a) вольтметру; b) амперметру.

Вправа 9. Прочитайте та перекладіть текст

INSTRUCTIONS

Current is the measure of the rate of electron "flow" in a circuit. It is measured in the unit of the Ampere, simply called "Amp," (A).

The most common way to measure current in a circuit is to break the circuit open and insert an "ammeter" in series (in-line) with the circuit so that all electrons flowing through the circuit also have to go through the meter. Because measuring current in this manner requires the meter be made part of the circuit, it is a more difficult type of measurement to make than either voltage or resistance.

Some digital meters, like the unit shown in the illustration, have a separate jack to insert the red test lead plug when measuring current. Other meters, like most inexpensive analog meters, use the same jacks for measuring voltage, resistance, and current. Consult your owner's manual on the particular model of meter you own for details on measuring current.

When an ammeter is placed in series with a circuit, it ideally drops no voltage as current goes through it. In other words, it acts very much like a piece of wire, with very little resistance from one test probe to the other. Consequently, an ammeter will act as a short circuit if placed in parallel (across the terminals of) a substantial source of voltage. If this is done, a surge in current will result, potentially damaging the meter:

Ammeters are generally protected from excessive current by means of a small fuse located inside the meter housing. If the ammeter is accidently connected across a substantial voltage source, the resultant surge in current will "blow" the fuse and render the meter incapable of measuring current until the fuse is replaced. Be very careful to avoid this scenario!

You may test the condition of a multimeter's fuse by switching it to the resistance mode and measuring continuity through the test leads (and through the fuse). On a meter where the same test lead jacks are used for both resistance and current measurement, simply leave the test lead plugs where they are and touch the two probes together. On a meter where different jacks are used, this is how you insert the test lead plugs to check the fuse:

Build the one-battery, one-lamp circuit using jumper wires to connect the battery to the lamp, and verify that the lamp lights up before connecting the meter in series with it. Then, break the circuit open at any point and connect the meter's test probes to the two points of the break to measure current. As usual, if your meter is manually-ranged, begin by selecting the highest range for current, then move the selector switch to lower range positions until the strongest indication is obtained on the meter display without over-ranging it. If the meter indication is "backwards," (left motion on analog needle, or negative reading on a digital display), then reverse the test probe connections and try again. When the ammeter indicates a normal reading (not "backwards"), electrons are entering the black test lead and exiting the red. This is how you determine direction of current using a meter.

For a 6-volt battery and a small lamp, the circuit current will be in the range of thousandths of an amp, or milliamps. Digital meters often show a small letter "m" in the right-hand side of the display to indicate this metric prefix.

Try breaking the circuit at some other point and inserting the meter there instead. What do you notice about the amount of current measured? Why do you think this is?

Re-construct the circuit on a breadboard like this:

Students often get confused when connecting an ammeter to a breadboard circuit. How can the meter be connected so as to intercept all the circuit's current and not create a short circuit? One easy method that guarantees success is this:

Identify what wire or component terminal you wish to measure current through. Pull that wire or terminal out of the breadboard hole. Leave it hanging in mid-air.

Insert a spare piece of wire into the hole you just pulled the other wire or terminal out of. Leave the other end of this wire hanging in mid-air.

Connect the ammeter between the two unconnected wire ends (the two that were hanging in mid-air). You are now assured of measuring current through the wire or terminal initially identified.

Again, measure current through different wires in this circuit, following the same connection procedure outlined above. What do you notice about these current measurements? The results in the breadboard circuit should be the same as the results in the free-form (no breadboard) circuit.

Building the same circuit on a terminal strip should also yield similar results:

the current figure of 24.70 milliamps (24.70 mA) shown in the illustrations is an arbitrary quantity, reasonable for a small incandescent lamp. If the current for your circuit is a different value, that is okay, so long as the lamp is functioning when the meter is connected. If the lamp refuses to light when the meter is connected to the circuit, and the meter registers a much greater reading, you probably have a short-circuit condition through the meter. If your lamp refuses to light when the meter is connected in the circuit, and the meter registers zero current, you've probably blown the fuse inside the meter. Check the condition of your meter's fuse as described previously in this section and replace the fuse if necessary.

Граматичний матеріал: Герундій

Герундій має властивості як дієслова, так і іменника. Подібної неособистої форми в українській мові немає. Як іменник він може виконувати в реченні функції підмета, додатка, означення та обставини з прийменником. Як дієслово може мати після себе прямий додаток і визначатися прислівником, мати доконану форму, категорію стану, а також виражати дію як процес. Герундій утворюється від основи дієслова за допомогою суфіксу -ing (to translate - translating, to read - reading)

	Active	Passive
Indefinite	writing	being written
Perfect	having written	having been written

Форми герундія збігаються з формами Partiсірle I і Perfect Participle. Проте,

це різні форми дієслова, що відрізняються і за значенням і за синтаксичними функціями. Форми In-definite Gerund позначають дії, одночасні з дією, вираженою дієсловом-присудком. He likes inviting friends to his place. -Він любить запрошувати друзів до себе. He likes being invited to his friends. - Він любить, коли його запрошують до себе його друзі. Доконані форми герундія (Perfect Gerund) позначають дії, що передують дії, вираженій дієсловом-присудком. He is proud of having invited this man to his place. - Він пишається тим, що запросив цю людину до себе. He was proud of having been invited to the party. - Він пишався тим, що його запросили на вечір.

У реченні герундій може бути:

1. підметом ( Перекладається іменником або інфінітивом).Smoking is not allowed here. -Курити (куріння) тут не дозволяється.Swimming in the lake is forbidden.- Купатися (купання) в озері заборонено. It’s no use waiting any more.- Марно чекати більше. It’s no good worrying now. - Тепер марно хвилюватися. Nice talking to you. - Приємно було поговорити з вами. No talking! -Не розмовляти! Cultivating soil is the task of cultivation machinery. – Обробіток ґрунту – завдання ґрунтообробних машин.

2. означенням ( Перекладається іменником або інфінітивом.)There are different ways of obtaining this substance.- Існують різні способи отримання цієї речовини. The methods of training specialists – методи підготовки спеціалістів

3. іменною частиною присудка (Перекладається іменником або інфінітивом. У цьому випадку герундій грає роль смислової частини присудка, слідуючи за дієсловом -зв'яз-кою to be (am, is, are, was, were,...) His hobby is driving a car. - Його хоббі – водіння (водити) машини. His task was translating the text from English into Russian. - Його завдання полягало в тому, щоб перекласти текст з англійської на російську.

4. частиною складеного дієслівного присудка I began listening to music when I was six. — Я почав слухати музику у шість років.

5. прямим додатком (Перекладається іменником або інфінітивом).. The car needs repairing.- Машина потребує ремонту I enjoy listening to music.- Мені подобається слухати музику.

6. прийменниковим додатком (Перекладається іменником або підрядним реченням.) They spoke about their travelling.- Вони говорили про свою подорож.

7. обставиною (завжди з прийменником). (Перекладається іменником з прийменником, дієприслівником, підрядним реченням.) Learning rules without examples is of little use. - Вивчення правил (вивчати правила) без прикладів приносить мало користі. Think before answering. - Подумай перш ніж відповісти.

Виконання вправ на закріплення граматичної теми

Вправа 10. Перекладіть українською.

1. I understand perfectly your wishing to start the work at once.2. The place is worth visiting. 3. Watching football matches may be exciting enough, but of course it is more exciting playing football. 4. Сheck before operating. 5. Who likes changing the bulb? 6. Improper use of appliances leads to a fire. 7. Unobserving of safety measures leads to injury. 8. Nobody likes to get bad marks.

Вправа 11. Розкрийте дужки. Вставте Gerund.

1. He was always ready for (to help) people. 2. He was very glad of (to help) in his difficulty. 3. On (to allow) to leave the room, the children immediately ran out into the yard and began (to play). 4. In (to make) this experiment, they came across some very interesting phenomena. 5. The results of the experiment must be checked and rechecked before (to publish).6. The equipment requires (to repair).

Заняття 40

Тема: Електричні вимірювальні прилади: електричної потужності, опору

Граматичний матеріал: Герундій

Вправа 1. Прочитайте та перекладіть лексику за допомогою словника.

іnstrument [ʹınstrəmənt]

sufficient [səʹfıʃ(ə)nt]

estimate [ʹestımıt]

switchboard [ʹswıtʃbɔ:d]

resemblance [rıʹzembləns]

portable instrument [ʹpɔ:təb(ə)l ʹınstrəmənt]

calibration [͵kælıʹbreıʃ(ə)n]

identical [aıʹdentık(ə)l]

consider [kənʹsıdə]

Вправа 2. Прочитайте та перекладіть текст українською.

Wattmeters

Instruments designed to measure the amount of power passing in a circuit are known as wattmeters.

In the case of D. C. circuits the power taken is the pro­duct of the voltage and the current flowing. Ammeter readings become almost a sufficient indication of the power taken and the installation of wattmeters an unnecessary expense.

Due to a factor which must be taken into account, namely, the power factor or phase relationship between the voltage and current, the power taken by even the simplest two-wire A. C. circuit is not so easily estimated. In some A. C. circuits, then, the installation of a wattmeter is necessary if the po­wer is to be measured.

Common forms of wattmeter, as installed on switchboards or as portable instruments, are of the dirеct-indicating type with pivoted moving elements. Other forms used as standard for calibration and classed as laboratory equipment have a torsion head suspension and are “indirect" reading.

Since their modes of operation are basically the same as certain types of ammeter and voltmeter, it is only to be expect­ed that their individual mechanical and electrical component parts are identical with or bear a close resemblance to those already considered. They will, in general, be restricted by the same errors and disadvantages, and will gain by the same advantages.