How to use a multimeter when repairing equipment
Use of the multimeter requires attention:
1) Identify the function of each multimeter gear.
2)Measure and record three - four resistances.
3)Measure AC voltage and record.
4) Measure DC voltage and record.
Multimeter: mainly used to measure AC DC voltage, current, DC resistance, and transistor current amplification. Nowadays, there are mainly digital multimeter and mechanical multimeter.
1) Digital multimeter
In the multimeter will see the conversion knob shown in the figure, the knob refers to the second amount of gear.
V~: It means the gear for measuring AC voltage.
V-: It means the position for measuring DC voltage.
MA: It means the position for measuring DC voltage.
Ω(R): It is the position for measuring resistance.
HFE: Measurement of resistance.
The red pen of the multimeter is connected to the positive pole of the external circuit, and the black pen is connected to the negative pole of the external circuit.
Advantages: anti-magnetic, easy to read, accurate (digital display) ......
2) Mechanical Multimeter
The appearance of the mechanical multimeter and the digital meter have some differences, but they are both similar to the shift knob, the gear is basically the same.
In the mechanical meter, there is a dial as shown in the figure, and there are eight scales on the dial:
Marked with "Ω" is the scale used to measure resistance.
Marked with "~" mark is the measurement of AC and DC voltage, DC current with the scale engraved.
Marked with "HFE" is a scale for measuring transistors.
Marked with "LI" is a scale for measuring load current and voltage.
Marked with "DB" is the scale for measuring the level.
3) Use of multimeter
① digital multimeter: before measurement, hit the measuring gear, it should be noted that the gear is marked on the range, that is, the * big value.
② Mechanical multimeter: Measure the current and voltage in the same way as the mathematical type, but the measurement of electric Yin, the reading should be multiplied by the value on the gear is the measured value. For example: now playing the gear is "X100" reading is 200, the measurement of the subject is 200X100 = 20000Ω = 20K, the dial "Ω" ruler is from left to right, from large to small, while the other is from left to right, from small to large!
4) Notes:
① adjust the "zero point" (mechanical table only), before using the table, first look at the pointer is pointing at the left end of the "zero position", if not, it should be a small screwdriver slowly rotate the case in the centre of the "starting zero" correction screw, so that the pointer is pointing at the zero position.
② multimeter should be placed horizontally when used (mechanical only)
③ test to determine the content of the measurement, the range conversion knob rotated to the corresponding gear shown in the measurement, in order to avoid burning the meter head, if not, the meter head will not be burned.
avoid burning the meter head, if you do not know the size of the physical quantity to be measured, start with a large range of trial measurement.
④Meter pens should be inserted in the corresponding sockets correctly.
⑤Do not rotate the knob of gear change during the test.
⑥After use, be sure to adjust the shift knob to the large range of AC voltage.
⑦ Measure DC voltage and current, pay attention to the positive and negative poles of the voltage, the current flow direction, and the pen connected to the meter.
In addition to multimeter, the company also has clamp meter, capacitance meter, LCR meter, square resistance tester, power quality analyser, etc., welcome to call us to postal advice.
