INGLESE TECNICO

MATERIALS USED IN ELECTRICAL ENGINEERING

INTRODUCTION

over the last half century  the use of electrical energy ha enourmously increased for virtually all domestic and industrial purpose
this fact is a proof that the electrical industry plays a most prominent part in the economy  of a country and in the history of its social progress
The large-scale  application of electrical energy has required an enormous investment in resources both  economic and human in many branches  of science
In connection with all other  problems however it is  the research on the materials  which  has alwuys been given special attention
Som materials have been selected  either for their electrical  and mechanical characteristics or for their  commercial availability
In order to improve properties suitable  for specific purposes Others have become object of research in laboratories financede from contributions of private  firms, often with adequate  assistance  from the state
Finally  it has been necessary  to find new materials  answering the requirements implied  by the develpmente of the electrical industry
Electrical materials can be classified in any number of Group according to their  main purposes and to their properties in individual applications
For general purposes they are  classified in five main Group  : conductors, insulators , semi-conductors, magnetic materials and refractories
Some materials  however may  serve hìother purposes besides those directly  related to  their main property
Iron for instance  is a magnetic material but is also used for constructional purposes  and with other elements in the form of a ferrous  alloy it is resistive condictor  as found in heating  elements

vocabulary
to finance = finanziare
refractory = refrattario
alloy = lega
resistive conductor = conduttore resistivo

guide to summery (riassunto )

answer with short complete sentences, then join them in a brief summary

1. during what period ha the use  of electrical energy enourmosly increased ?
2. what does this increase  prove ?
3. what has the large-scale application  of electrical energy required ?
4. what type of research has alwuys been given special attention ?
5. what considerations have  led to the  selection of appropriate materials ?
6.what was done in order to improve  properties suitable  for specific purposes ?
7. did the research on known materials answer satisfactorily the requirements of the modern electrical industry ?
8. how are materials classified ?
9. the five main groups taken into account for general purposes

WORD STUDY AND PATTERNS

EITHER , WETHER , BOTH

either is used in order to emphasize an alternatives  while both will espress the combination of two thngs (nouns verbs etc.) compare the two sentences :

I hoper he can speak either French or German (I hope he speaks al least one of these languages)
either Language will do I speak both
I speak both French and German

the possibility of an alternative con also expressed emphatically by whether  which is used  when there is a strong possibility that the action or condition espressed by the verb that follo ws may no come true or may have different  result
Most time it can be replaced by if

I don't know                                                          it will work satisfactorily (or not)
you must ask                                 whether           they are ready to accept a long delivery period
it is necessary to determine                if                the voltage  applied is correct
it remains to be seen                                             the fault is caused by manipulation or defective insaulation

whether amy also refer to two  or more possibilities  which will not change what is stated  in the main  calusa
It cannot be replaced by if in this case

whether due high cost or poor efficiency this produco did not sell seccessfully on foreign markets
prices  of raw materials will increase seadily whwthwe we like it or not