Active-PassiveThe development of electonics (1) _wasinvented_____ (invent) by the invention of thevacuum tube. In 1947, transistor (2) _wasfound____ (find). The devices by the time (3)___were__ (to be) different. Many people (4)_used___ (use) the devices rarely. In 1958, thedevelopment of Ics (Integrated Circuit) on siliconchips (5) ___made__ (make) people use theelectronics everyday. At present, the introductionof microprocessor (6) ___allows__ (allow)electronics to (7) ___broaden__(broaden) variouselectronics equipments such as automatic washingmachine, dishwasher, central processing unit.
EXERCISE 2Alexander Graham Bell (1) __invented____(invent) the telephone in 1978. He (2) ___was_ (be) a Canadian whose family (3) _came___ (come) from Scotland. Since then, telephone system (4) __grew__ (grow) dramatically; in the UK alone there (5) _are__(be) now over 24 million lines. Formerly, the UK system (6) __is_(be) analogue. Many changes (7) _take place___ (take place) in recent years. Almost entire UK network (8) _is__ (be) now digital. Fibre optic cables (9) ___replace___(replace) the old copper lines. Previously, telephone exchanges (10) _are used____(use) banks of electromagnetic relays for switching. Today, they (11) ___have__ (have) computer-controlled units. The new network (12) _is___ (be) fast and reliable.
Microcomputer system The I/O (input/output) unit consists of one or more Ics, whichare used to control the data going in and out of the computer. TheROM (read-only memory) and RAM (random-access memory) unitsconsist of a number of special digital logic chips which can storeprograms and data. The small ROM provides some permanentstorage and the RAM is used for temporary storage. Unlike theROM, the contents of the RAM is constantly changing, but it onlyoperates while the computer is switched on. The CPU (central processing unit) is a microprocessor. It is themain part of the computer, which controls the rest of the systemand performs all the arithmethic and logic operations on the data. Sets of connectors known as buses are used to carry theinternal signals between each unit. The data bus is used to transferdata between all the units. The control bus is used to send controlsignals from the CPU to the other units. The address bus is used tosend signals from the CPU which indicate the memory and I/Olocations to be used.
Fill in the gaps in this table based on the text aboveComponent PurposeI/O unit Controls data going in and out of the computer Store program and data Temporary storageCPU To transfer data between unitControl bus Sends signals from the CPU which indicate the memory and I/O locations to be used
Reading Comprehension: Answer these questions based on the text above1. What does the text inform you?2. What is the difference between RAM and ROM?3. How do the buses work?4. Draw a diagram that describe the information on the text!
Read the text carefully and fill the blanks with suitable verbs (active or passive) The Electric Motor In an electric motor, an electric current and magnetic field (1) ______produces_ (produce) a turning movement. This can drive all sorts of machines, from wrist-watches to trains. An electric current running through a wire produces a magnetic field around the wire. If an electric current (2) __flows____ (flow) around a loop of wire with a bar of iron through it, the iron becomes mangnetized. It (3) __is called___ (call) an electromagnet; one end becomes a north pole and the other a south pole, depending on which way the current is flowing around the loop. If you put two magnets close together, like poles—for example, two north poles—repel each other and unlike poles attract each other. In a simple electric motor, a piece of iron with loops of wire round it, called an armature, (4) ___is placed___ (place) between the north and south poles of stationary magnet, known as the field magnet. When electricity flows around the armature wire, the iron becomes an electromagnet.
The attraction and repulsion between the poles of thisarmature magnet and the poles of the field magnet (5)___makes__ (make) the armature turn. As a result, its northpole is close to the south pole of the field magnet. Thecurrent (6) __reverses____ (reverse) so the north pole of thearmature magnet becomes the south pole. Once again theattraction and the repulsion between it and the field magnetmake it turn. The armature continues turning as long as thedirection of the current, and therefore its magnetic poles,keeps being reversed. To reverse the direction of the current, the ends of thearmature wire (7) ___is connected____ (connect) to differenthalves of a spirit ring called a small carbon blocks calledbrushes. As the armature turns, first one half of thecommutator comes into contact with the brush deliveringcurrent, and then the other, so the direction of the currentkeeps being reversed.
Skim the text and identify the paragraphs which containinformation on each of these topics. The first has been donefor youa. What electric motors are used for Paragraph 1b. The commutator _________c. Why the armature turns _________d. Electromagnets _________e. Effect of putting magnets together _________f. The armature _________
Answer these questions based on the text!1. What does this text inform you?2. What does the electric motor do?3. Mention the components of electric motor?4. What is the function of commutator?5. What does “this” (P1) refer to .....6. What does “it” (P4) refer to ........