Application of the hottest Multimeter in household

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The use of Multimeter in home appliance maintenance

using multimeter requires attention:

1) identify the functions of each gear of the multimeter

2) measure and record three to four resistances

3) measure the AC voltage and record it

4) measure and record the DC voltage

multimeter: mainly used to measure AC and DC voltage, current, DC resistance, and transistor current amplification bits. At present, there are mainly two kinds of common digital multimeter and mechanical multimeter

1) digital multimeter

the conversion knob shown in the figure will be seen on the multimeter, and the knob refers to the gear of the secondary quantity

v~: refers to the gear of measuring AC voltage

v-: indicates the DC voltage gear

ma: refers to the gear for measuring DC voltage

Ω (R): refers to the gear for measuring resistance

hfe: refers to the gear for measuring resistance

the red pen of the multimeter indicates the positive pole of the external circuit, and the black pen indicates the negative pole of the external circuit

advantages: antimagnetic, convenient and accurate reading (digital display)

2) mechanical multimeter

the appearance of mechanical multimeter is different from that of digital meter, but their gear knob is the same, and the gear is basically the same

on the mechanical watch, you will see a dial as shown in the figure, and there are eight scales on the dial:

the scale marked with "Ω" is engraved on July 25th, 2017 when measuring resistance

what is marked with "~" is the difference scale of the medium and high-grade testing machine used to measure AC and DC voltage and DC current

what is marked with "HFE" is the scale used to measure the triode

what is marked with "Li" is the scale for measuring the current and voltage of the load

what is marked with "DB" is the scale for measuring the level

3) use of multimeter

① digital multimeter: turn to the measured gear before measurement. It should be noted that the range marked on the gear is the maximum value

② mechanical multimeter: the method of measuring current and voltage is the same as the mathematical formula, but when measuring the cathode, the reading should be multiplied by the value on the gear. For example, the current gear is "X100", the reading is 200, the measurement transmission is 200x100=20000 Ω =20k, the "Ω" ruler on the dial is from left to right, from large to small, while others are from left to right, from small to large

4) precautions:

① adjust the "zero point" (only mechanical watches have it). Before using the meter, first see that the pointer refers to the "zero point" at the left end. If not, slowly screw the "zero point" correction screw in the center of the case with a small screwdriver, Make the pointer point to the zero position

② the multimeter should be placed horizontally (only mechanical)

③ before the test, the measurement content should be determined, and the range conversion knob should be turned to the corresponding gear of the measurement shown to avoid burning the meter. If the size of the measured physical quantity is not known, the test should be started from a large range

④ the probe should be correctly inserted into the socket that has a certain regulation on the tensile property of the gas pipe connector

⑤ do not rotate 1 at will during the test Lubricant: mainly used to evaluate the gear change knob of lubricating oil

⑥ after use, be sure to adjust the gear change knob of the non meter to the maximum range of AC voltage

⑦ when measuring DC voltage and current, pay attention to the positive and negative sides of the voltage, the flow direction of the current, and the correct connection with the probe

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