After entering the third year of junior high school, students will usher in a brand new knowledge module. This knowledge module has a large content and a large proportion of the high school entrance examination. It is one of the two most important modules of junior high school physics!
There are two so-called knowledge modules: one is mechanics, which is the knowledge of various mechanics in physics in the second grade; the other is electricity, which is the knowledge of electrics that students of junior high school will face in the first half of the semester.
It can be said that the status of these two knowledge modules in the senior high school entrance examination is very stable, and the combined total is about 70%! And electrical knowledge is more than 30%!
Therefore, only if you learn electricity well can you get a high score in physics.
However, when learning electrical knowledge, you will encounter various questions and problems, such as the identification of complex circuits, dynamic changes of circuits, circuit failures, gear problems, and comprehensive electrical power problems. ......
There is another type of question type, which belongs to the high school entrance examination, which is usually done, but it is a type of electrical problem that is very troublesome for many junior students: circuit design problems.
Regarding circuit design, is there any way or way to quickly grasp the method and get full marks?
Actually, there are methods. Just like any method, you must first understand, remember, and use flexibly in order to be handy.
The steps of designing the circuit:
1. First, determine the circuit connection mode (series connection? Parallel connection?) according to the function and circuit characteristics of the circuit;
2. Draw the schematic diagram of the circuit, according to the switch in the circuit The function is connected in the appropriate position;
3. Combine the sketch with the meaning of the question and verify it repeatedly;
4. Draw a standard and beautiful circuit diagram.
The most important thing is the following circuit types that need to be understood, mastered, and skillfully used:
1. Switch series: If two switches are closed at the same time,The circuit can work normally. If one of them is not closed, it cannot work. At this time, the two switches are connected in series! (for example, two keys control an electric door)
2. The switches are connected in parallel: If you close any switch, an electrical appliance can work normally, then it is connected in parallel, and the electrical appliance is on the main circuit! (such as smart door locks, you can open the door as long as you enter a password or identify your fingerprint)
3. The switches are controlled separately: In a parallel circuit, each branch switch independently controls the branch and each consumer Can work at the same time or independently ; (for example, a washing machine with drying function requires washing and drying to be carried out independently)
4. Switch sequence control: if it is an electrical appliance and then another Only one electrical appliance can work, then two electrical appliances are connected in parallel, the first one is controlled by the main circuit switch, the latter is controlled by the branch switch; (such as a hair dryer with cold and hot air functions)
5. Local short circuit ： When the switch is closed, a certain consumer does not work. When the switch is opened, the consumer works, and the two are connected in parallel, that is, the consumer is partially short-circuited; (such as an explosive device)
6. Multi-switch combination control: If there are three or more switches to control the same electrical appliance,If a certain main switch plus any auxiliary switch can control the same consumer, then the two are located in the main circuit, and the rest are located in the branch circuit! (such as smart unlocking, main and deputy referee problems)
Similar related problems, students will often encounter in future studies, as long as the above conclusions are used proficiently, they can quickly master the problem-solving methods and use them flexibly.
More electrical knowledge induction, method summary, error-prone points, frequently wrong questions, difficult points, common compulsory examination conclusions, all in "One week proficient in electrical science, easy entrance examination!"
middle school students friends, develop Be good at summarizing good habits, for a better future, come on!
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