Know the ammeter

Current is an important physical in the electrical, ammeter is the measurement of the current size of the tool, as shown in our micro-physical test box and the school laboratory provided the same DC ammeterPlease observe the physical ammeter, answer the following questions:

(A) to explore and think

(1) & nbsp; What signs are used to confirm the ammeter? What are the symbols and numbers on the terminal?

(2) & nbsp; ammeter has several ranges? What is the scale value for the different scale dials?

(3) & nbsp; how to read the current value indicated by the pointer?

(4) & nbsp; There are three terminals on the ammeter, how to access the ammeter circuit? What should I pay attention to when using the problem?

(B) understand the ammeter signs, range and scale values

Carefully observe the ammeter can be seen, there is a dialA", Which is the ammeter of the sign that the meter is ammeter; use ammeter before the measurement, first of all to understand the ammeter range and scale value, so as to quickly and accurately read.

Range is the measurement tool measurement range, as shown in the figure can be seen on the ammeter dial there are two lines, the above isBEHIND", The following line is"0. & lt; / RTI & gt;In other words, this ammeter has two ranges.

So how do you use these two ranges when you use it? It depends on the ammeter above the terminal, and we can see that we use this ammeter has three terminals, of which two red is the front post, which is the black negative terminal, two red post The following are written separately"with""Access to the circuit, can only access two terminals at the same time, must be a black terminal (negative terminal) and a red terminal (positive terminal), so that the ammeter access circuit only two Connection: the first connection as shown in Figure, Marked withOf the terminal and marked with a "-" black terminal access circuit, this time that the choice of "0. & lt; / RTI & gt;"The range; the second connection, as shown in Figure, Marked ""Red terminal and marked with" - "black terminal access circuit, said the choice is"BEHIND"Range.

FigureFigure

Scoring value is the smallest size of the measuring instrument size, we can use this ammeter can be seen, regardless of which two range, are fromTo the maximum scale are divided into three cells, each cell is divided equallySmall grid, the size of each small cell is the scale value; through observation and analysis we can see that in the choice of "0. & lt; / RTI & gt;Of the range, each small grid said,this means"0. & lt; / RTI & gt;"The division value is; Similarly,BEHIND"The scale value of the range is