29 3-45.   The FOCUS control on the front of an oscilloscope is used to adjust what characteristic on the CRT display? 1.   Beam size 2.   Beam location 3.   Trace position 4.   Beam brilliance Figure 3B.—CRT traces.   IN ANSWERING QUESTIONS 3-46 THROUGH 3-48, REFER TO FIGURE 3B.   3-46.   What trace in the figure should you correct by adjusting ONLY the HORIZONTAL POSITION control? 1.   A 2.   B 3.   C 4.   D 3-47.   What trace in the figure should you correct by adjusting ONLY the VERTICAL POSITION control? 1.   A 2.   B 3.   C 4.   D 3-48.   In the figure, what trace would be corrected by adjusting both the HORIZONTAL POSITION and VERTICAL POSITION controls? 1.   A 2.   B 3.   C 4.   D 3-49.   What is the purpose of the deflection amplifiers in a cathode-ray oscilloscope? 1.   To isolate the input signal from the vertical deflection plates 2.   To increase the amplitude of the signal applied to the vertical deflection plates 3.   To eliminate distortion of the CRT beam 4.   To position the beam on the CRT 3-50.   What control on the front panel of an oscilloscope limits the input signal amplitude and allows the oscilloscope to be used with a wide range of signals? 1.   TIME/CM 2.   TIME BASE 3.   ATTENUATOR 4.   TRIGGER 3-51.   What is the purpose of a variable potentiometer mounted on the VOLTS/DIV control of an oscilloscope? 1.   To provide definite step control of the input signal 2.   To provide fine control of the input signal 3.   To provide fine control of the output signal 4.   To provide definite step control of the output signal 3-52.   The time base of an oscilloscope is variable to enable the instrument to 1.   measure low- and high-amplitude signal voltages 2.   operate over a wide range of input frequencies 3.   make accurate measurements of signal amplitudes 4.   accurately position the presentation on the CRT