4.3.6　Analysis and questions

(1)If you want to get a light spot,a horizontal line,a vertical line,and a 50 Hz sine waveform on the oscilloscope.Then knobs should be adjusted respectively and try to describe how to connect the electrical wires.

(2)If you use a positive sawtooth wave to scan from left to right,the sine wave displayed on the phosphor screen is a bit unstable,and the waveform keeps running to the right.Is the frequency of the sawtooth wave higher or lower?Why?How to adjust to make it stable?(https://www.daowen.com)

(3)When observing the Lissajous figure,is the“X axis selection”placed at the scanning position or at the X axis attenuation position?Does the scan range,scan fine-tuning,and synchronization selection affect the Lissajous graphics?

(4)If there is no light spot on the screen after turning on the power switch of the oscilloscope,what are the possible reasons?How should they be adjusted separately?