9. Answer the questions.

a) What must be done when it is necessary to change a fuse?

b) Tell the basic aim of using a ground fault circuit interrupter.

c) What can prevent an electrical shock?

d) How must the place where electrical repairs are be marked?

e) What requirements are there for special clothes?

f) Why is electrical current dangerous?

g) How can an electrical shock be avoided?

10. Write a memory card with safety rules for beginners who start working with electricity. Unit 3 electrical measuring instruments

1. Do you know

a) what electrical measuring instruments are used to measure current, voltage, and resistance?

b) how an ammeter must be inserted into a circuit?

c) how a voltmeter must be inserted into a circuit?

d) what is AC and DC?

e) that the German schoolmaster, Georg Simon Ohm, discovered the relationship between voltage, current, and resistance? Do you know his law?

2. Learn the words. to check – проверить cell - элемент

accurately – точно quantity - количество

ammeter – амперметр voltmeter - вольтметр

ohmmeter – реостат moving-coil - подвижная катушка

torque – крутящий момент damp – заглушать damping - заглушка

to calibrate – калибровать analogue multimeter – многофункциональный счётчик

digital – цифровой precision – точность

permanent – постоянный pole – поле, полярность

scale – шкала pointer – стрелка

copper wire – медная проволока bearing – подшипник

spring – пружина zero set adjustment – нулевой регулировщик

to connect – соединять in series – последовательно

in parallel (across) – параллельно to rotate - вращать

3. Make the word combinations.

1. calibrate	in series	1. to damp	of the ammeter
2. to measure	a moving coil	2. to rotate	the ohmeter
3. to connect	electrical current	3. the precision of	the scale
4. the copper wire of	the scale	4. the scale	the coil
5. the quantity of	measuring instrument	5. to check	measurements
6. digital	accurately	6. zero adjustment of	the pointer

4. Make the sentences out of the given words.

1. is, a circuit, in, Ammeter, series, connected, in.

2. resistance, have, Ammeters, low, a, internal, very.

3. with, amperage and voltage, Electrical, accuracy and precision, instruments, great, measure.

4. a circuit, are, parallel, connected, in, always, in, Voltmeters.

5. the resistance, to, use, an ohmmeter, a circuit, We, measure, of.

The ‘moving-coil’ is the most common type of meter movement employed by precision analogue instruments such as ammeters, voltmeters, ohmmeters, and multimeters. Its main components are illustrated below:

6. live, an ohmmeter, Never, circuit, connect, to, a.