2019/7/4 learning summary

2019/7/4 learning summary

Experiment: Parallel voltage negative feedback amplifier circuit

The main task today is to experiment, and there are many setbacks, so I will summarize now.

Morning: theoretical preparation, determine the subject of the experiment

There are many difficulties in reading the negative feedback circuit diagram. Stumbled and stumbling thinking, vague thinking.
Solution: (also should be used for reference when reading the literature in the future)

• When you get lost, look at the subtitle first . The subheading is the core information, it enables you to grasp the core of the current discussion.
• Don't try to "sweep" word by word. We must focus our energy on thinking and try to grasp the author's logical chain. After reading each section, be sure to ask yourself what this want to tell yourself, then mark draw out your have experience places, and annotate in place. After finishing these tasks, you can proceed to the following reading. After finishing the reading of a chapter, you should do some thought replays to see your own reading effect.
• When your own thoughts conflict with the book, first think about it again. If you feel that there is an unexplainable contradiction between the two sides, write it down, ask others, and don't bother.
• When doing reading, put aside other tasks. Yes, theoretical study may be time-consuming, but theoretical study is indispensable. Concentrating on a certain time of the day to break an important thing is a manifestation of high efficiency.
  In short, in the morning study, it was determined that the biggest problem encountered in making a parallel voltage negative feedback amplifier circuit : the parameters of several components in the circuit diagram cannot be determined. The related problem is the incomplete calculation method.

Afternoon: From drawing circuit diagrams to PCB printing-insufficient preparation and too many situations

In the afternoon, from drawing the schematic circuit diagram -> PCB wiring, the problem of unskilled and rough finished products was exposed. This is understandable: I haven't done much of this kind of work, and there is no systematic study and practice. However, the process of printing and making the board (including transfer, drilling, and corrosion) was too bad. In the end, it was forced to stop production because of the problem of not knowing that the corrosive liquid was gone. The person in charge of the drugs happened to be sleeping again. In addition, there are a lot of things that I didn't bring from the dormitory, and I ran at least 3 times from the laboratory to the dorm. It is inefficient to start printing the whole afternoon.
Lesson: You should prepare the materials that may be used in each step of the experiment in advance, and do the experiment after you have a basic understanding of each process of the experiment. Don't hesitate to ask in time when you encounter problems that must be solved by others in the experiment.

Evening: Alternatives-breadboard, blind parameters lead to unsatisfactory results

Thinking of using a breadboard can be said to be a "no way", and the breadboard cannot be practiced for soldering. But regardless of these flaws, the breadboard was built up according to the circuit in the book. In the meantime, the pin header was used as the port, but the effect was not satisfactory. Later, the small green port was used to solve the problem. But the problem in the morning is still unsolved: I don't know the resistance value. It is difficult to solve this problem when analog circuits and circuit theory are not perfect. I didn’t ask in time, but I first checked the information on a "similar" circuit on the Internet, and copied two resistance values. The laboratory did not have the right resistance, so I found two similar ones and put them on psychologically. Anxious to see the results.
The result was also expected, and no amplification was achieved. Only then did I remember to ask. Asked an artifact: circuit simulation! I also confirmed that the calculation method is in "Analog Circuit".
Self-taught technology will always make progress as long as you do it. The key is to seize the initiative in development. The current situation is: lack of knowledge and insufficient theory. Even less experience. Learning to ask some key technical questions can open up the situation. It is necessary to attach great importance to the systematic development of theories, and notes must be adhered to. And to reform the form to make it more practical and not time-consuming.