1 Look at the schematic diagram in the figure above The osci

1.   Look at the schematic diagram in the figure above. The oscillator shown generates a sine wave with a small DC component. The waveform produced by the oscillator is shown on the oscilloscope. The thermistor in the circuit has a positive temperature coefficient. What will happen to the waveform of this circuit if the temperature rises?

A. The amplitude of the waveform will decrease. B. The waveform will drift downward on the oscilloscope screen. C. The amplitude of the waveform will increase. D. The waveform will drift upward on the oscilloscope screen. 2.   This question is based on the figure above. The oscilloscope screen shown is set to display 5 volts per division vertically and 5 microseconds per division horizontally. What\'s the frequency of this waveform?      A. 1 kHz B. 100 kHz C. 1,000 Hz D. 10 kHz 3.   To center the waveform on the oscilloscope display in the figure above, which of the following controls would you use?      A. The time base control B. The vertical sensitivity control C. The vertical positioning control D. The sync amplitude control 4.   Light is often used to couple signals between circuits in which noise pickup is a factor. Of the symbols that are represented in the figure, which of the following are likely to be used for this purpose?      A. Symbol A, symbol C, and symbol E B. Symbol A and symbol B C. Symbol A, symbol B, symbol C, symbol E, and symbol G D. Symbol A, symbol C, symbol D, symbol E, and symbol 5.   Of the symbols that are represented in the figure, you would need to carefully observe the polarity if you were replacing      A. symbol A, symbol B, symbol C, symbol E, and symbol G. B. symbol A, symbol C, and symbol D. C. symbol A, symbol C, symbol D, and symbol E. D. symbol A, symbol C, symbol E, and symbol G.

Solution

1. The amplitude of the waveform will decrease.

explanation: thermistors with high positive temperature is only between a certain range of temperature, outside the range the temperature coefficient is either 0 or negative. it causes power dissipation. As the current increases , a peak is reachedat which the heating effect of the current begins to significantly change the thermal resistance and produces reduction in voltage across the device.

2. 10KHz

3. the sync amplitude control

6. The modulator now operates at a higher level of efficiency than before.

7. There\'s still room to increase the amplitude of the modulating signal without introducing distortion.

9. reduced to 960 .

10. 7.07 V.

11.The horizontal positioning control

12.There are four times as many turns in the secondary as in the primary.

13. The amplitude of the modulated carrier will increase

14. a negative DC component is riding on the waveform

16. At point 2 and point 4