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EXERCISES. 1. What can be summarized in the triode's characteristic performance curves?
I. Review questions: 1. What can be summarized in the triode's characteristic performance curves? 2. When are static triode characteristics obtained? 3. What does the plate current-plate voltage characteristic show? 4. What section of plate current-plate voltage characteristic is linear? 5. Why are variable voltage dividers connected across the plate voltage and grid voltage supplies? 6. What is measured by voltmeters and amperemeters while determining a family of plate current-grid voltage characteristics? 7. How are triodes almost always operated? 8. What for can the circuit in Fig. 3 be used? 9. What influence has the increase of the grid voltage on the plate current? 10. When does grid current decrease? II. Make up an abstract of the text basing on the answers III. Translate these international words without a dictionary: IV. Which of the following words are adjectives? А В C D 1. equation equal equally equalize 2. useful user uselessness usage 3. valued valuation valuable valueless 4. variety various variously variation 5. operate operator. operative operation 6. electric electrify electrician electricity 7. dependable dependence dependency dependent 8. import importance important importer V. Translate these synonyms and memorize them: 1. denote (v), mean, indicate, express, show, mark 2. explore (v), research 3. keep (v), retain, hold, preserve 4. actually (adv), really 5. various (adj), different 6. intersect (v), cut, cross 7. ascertain (v), determine, define 8. shape (n), form 9. in addition (to) (prep), besides VI. Translate these words and word combinations and learn them: respectively, either, in addition (to), evidently, along with, rarely, even, while, slightly, fairly Test 1 Find the correct answer out of the three given to each question; 1. Which of the following tubes consists of three elements: 2. Which of the following elements was added to form a a filament, a control grid, a plate 3. Which of the following elements has a controlling effect a cathode, a plate, a grid 4. Which of the following elements is connected with a high positive voltage: a plate, a cathode, a grid 5. Which of the following elements is connected with a low a grid, a cathode, a plate 6. Which of the following voltages is an alternating vol a bias voltage, a signal voltage, a plate battery voltage Test 2 I. Find Russian equivalents for the English verbs (see p. 148): 1. consist of (а) требовать 2. varyj (b) состоять из 3. govern (с) усиливать amplify (d) приводить к 4. add (e) работать 5. provide/ (f) называть 6. operate (g) обеспечивать 7. call (h) прибавлять 8. require (i) управлять
10. result in (j) изменяться 11. Find Russian equivalents for the English words and 1. under... conditions (а) действительно 2. no longer (b) следовательно 3. similar (с) больше не 5. thus (e) подобный 6. further (f) до некоторой степени 7. somewhat (g) или... или - 8. either... or (h) дальше, затем 10. actually (j) таким образом III. Find Russian equivalents for the English words and 1. in addition (to) (а) соответственно 2. even (b) очевидно 4. along with (d) каждый, любой 5. rarely (e) даже 6. while (f) помимо (кроме) 7. fairly (g) в то время как 8. either (h) незначительно 10. evidently (j) довольно, совершенно IV. Match these synonyms (see pp. 148) -2. control (v) (b) retain 3. connect (c) indicate 4. naught (d) usually 5. keep (e) govern 6. denote (f) name 7. generally (g) entirely 8. call (v) (h) give rise to 9. cause (v) (i) with regard to Test 3 Find a synonym (a), (b), (c) or (d) to the word or word combination in bold type: 1. The voltage placed on the grid — (a) measured; (b) changed; (c) increased; (d) put 2. The great quantity — (a) space; (b) area; (c) amount; 3. To aid the plate voltage — (a) change; (b) help; (c) vary; (d) cause 4. The different voltage — (a) various; (6) suitable; 5. A suitable instrument — (a) new; (b) rare; (c) pro 6. In addition to this fact — (a) therefore; (b) besides; 7. To differ rarely from — (a) completely; (b) entirely; 8. To explore a problem — (a) know; (b) discuss; (c) speak 9. To obtain positive charges — (a) produce; (b) attract;
10. To give rise to electrization - (a) use; (b) cause; 11. The electrons can pass through — (a) must; (b) should; (c) are able to; (d) will 12. To present a picture — (a) draw; (b) see; (c) discuss; (d) represent 13. The form of the tube — (a) size; (b) shape; (c) qual 14. To damage a device — (a) repair; (b) manufacture; 15. To remove the grid — (a) add; (b) make; (if) draw 16. To manufacture the electron tubes — (a) construct; 17. To control the flow of current — (a) regulate; (b) vary; (c) stop; (d) produce 18. To ascertain the voltage — (a) amplify; (b) deter 19. To be closer to the grid — (a) nearer; (b) far from; (c) within; (d) away from 20. To cut the lines of force — (a) fix; (b) intersect; Test 4 Finish each sentence choosing one of the three variants (a), (b) or (c) based on the texts from Section IV: 1. A triode has... (a) one element; (b) two elements; (c) three elements. 2. A triode consists of... (a) the control grid and the plate; (b) the cathode alone; (c) the cathode, the plate and the control grid. 3. The control grid is... (a) between the cathode and the plate; (b) behind the plate of the diode; (c) behind the cathode of the 4. A vacuum triode is... (a) a more simple device than a vacuum diode; (б) а more complicated device than a vacuum diode; (c) similar to a vacuum diode. 5. When a voltage is placed on the grid it has a profound (a) the electric field between cathode and plate; (b) the form of the plate current; (c) the form of the 6. The plate of the tube is normally connected to... (a) a low positive voltage; (b) a high positive voltage; (c) a negative voltage. 7. The heater is connected to... (a) a relatively low voltage; (b) the highest voltage; (c) the source of the plate voltage. 8. The plate of the tube is connected to a high positive (a) to repel the stream of electrons; (b) to attract the stream of electrons; (c) to cut off the stream of electrons. 9. A relatively low voltage ac or dc is connected to the (a) to produce a supply of electrons; (b) to create a supply of positive charges; (c) to govern the flow of plate current. 10. A voltage is placed on the control grid... (a) to create a supply of electrons; (b) to heat a cathode; (c) to govern the flow of plate current. 11. One of the components is a fixed dc voltage, called... (a) the signal voltage; (b) the bias; (c) the transient voltage. 12. The purpose of the bias voltage is... (a) to vary the flow of plate current; (b) to govern the electric field; (c) to bias the grid of the tube. 13. Superimposed upon the bias voltage is a voltage usually (a) the signal voltage; (b) the bias; (c) a fixed dc voltage. 14. A small variation of the signal voltage on the grid... (a) results in a large variation of the plate current through the tube; (b) has no influence at all on the plate current; (c) results in a small variation of the plate current through the tube. 15. The smallest negative voltage between the grid and the (a) the plate voltage; (b) the cut-off bias; (c) the zero grid bias. 16. The plate current is measured by... (a) a wattmeter; (b) a voltmeter; (c) a milliamperemeter. 17. A tiny change in the grid voltage can cause... (a) no change in the plate current; (b) the rectifying of the electric current; (с) a large change in the plate current. 18. The signal voltage appearing at the grid... (a) is not changed; (b) is amplified in the plate circuit of the tube; (c) is rectified in the plate circuit of the tube. 19. The function relations between plate voltage, grid vol- (a) a family of triode characteristic curves; (b) the diode characteristic curves; (c) the single characteristic curve. 20. Static characteristics are obtained... (a) under actual operating conditions; (b) when steady dc voltages are applied to the tube's electrodes; (c) when varying voltages are applied to the tube's electrodes. (See keys to the tests on p. 148.) Translate into Russian using a dictionary. * TRIODE CONSTANTS 1. The families of triode characteristics, which show the characteristic performance of each type of tube are not a result of accident. Rather they represent the outcome of
purposeful design to make each tube behave in a certain manner. The design factors of the tube are summarized by a series of numbers, called the tube constants. The three most important constants are the amplification factor, the ac plate resistance and the transconductance. 2. The amplification factor of a triode is a measure of 3. We can define the amplification factor by the follow amplification factor where 4. The plate resistance describes the internal resistance 5. where ΔIa — a small change in plate current. 6. A third constant used in describing the properties of 7. It is defined as the ratio of a small change in plate transconductance, 8. All the three constants m, Ri, S may be derived from the anode or anode-grid tube characteristics. If two of them are known the third one can be easily found, for the following equation will always be true:
The tube constants mentioned above are widely used in designing and analyzing electronic tube circuits. (See the Russian translation of this text on pp. 150-151) SECTION FIVE I Дата добавления: 2015-09-27 | Просмотры: 862 | Нарушение авторских прав |
(with Ia constant),
— a small changein plate voltage and 
—a small change in grid voltage.
Expressing this definition in equation forms we assume:
(with Ea constant).