How to use a multimeter
A multimeter is an essential test tool in electronic production. It has various functions such as measuring current, voltage and resistance.
This section will introduce the structure of the multimeter and how to use the multimeter. Students should work hard to learn to use a multimeter.
1. Observe and understand the structure of the multimeter.
There are many types of multimeters with different shapes, but the basic structure and usage are the same. The structure and shape of the commonly used multimeters are shown in the attached drawings on the color pages.
On the multi-purpose panel, there must be a meter head and a selector switch. There is also an ohm gear zero adjustment knob and a test lead jack. The functions of each part are described below:
(1) Header
The head of the multimeter is a sensitive galvanometer. The dial on the head is printed with various symbols, scale lines and numerical values (as shown in Figure 3-4(B)). The symbol A-V-Ω indicates that this meter is a multimeter that can measure current, voltage and resistance. There are multiple scale lines printed on the dial. The resistance scale line marked with "Ω" on the right end is zero on the right end and ∞ on the left end. The distribution of scale values is uneven. The symbol "-" or "DC" means direct current, "～" or "AC" means alternating current, and "～" means the scale line shared by alternating current and direct current. The lines of numbers under the scale line are the scale values corresponding to the different positions of the selector switch.
There is also a mechanical zero adjustment knob on the watch head to correct the pointer to zero at the left end.
(2) Selector switch
The selector switch of the multimeter is a multi-position rotary switch. Used to select measurement items and ranges. (As shown in Figure 3-4(B)). General multimeter measurement items include: "mA"; DC current, "V": DC voltage, "V": AC voltage, "Ω": Resistance. Each measurement item is divided into several different ranges for selection.
(3) Test pen and test pen socket
The test pens are divided into red and black. When using, the red test lead should be inserted into the jack marked with "+", and the black test lead should be inserted into the jack marked with "-".
2. How to use the multimeter
(1) Before using the multimeter, it should be done:
1. The multimeter is placed horizontally.
2. Check that the hands stop at the zero position on the left end of the dial. If there is any deviation, use a small screwdriver to gently turn the mechanical zero adjustment knob on the watch head to make the watch pointer point to zero.
3. Insert the test leads into the test lead jacks as required above.
4. Turn the selector switch to the corresponding item and range. is ready to use.
(2) After the multimeter is used, it should be done:
1. Pull out the test leads.
2. Rotate the selector switch to the "OFF" position, if there is no such position, it should be turned to the maximum range of AC voltage, such as "1000V again".
