A multimeter is a commonly used test tool. It is mainly used to test parameters such as voltage, resistance, and current. It plays a great role in the testing, maintenance and production of electronic products. The main components of a multimeter are an ammeter, a dial, a range selection switch, and test pens. There are many models of multimeters, but basically the method of use is the same.
This article mainly introduces how to use a multimeter to measure AC voltage and zero live wire step tutorial and precautions:
How does a multimeter measure AC voltage
1. Measurement method of AC voltage
1. Insert the black test lead into the COM jack and the red test lead into the V/Ω jack.
2. Set the function switch to the AC voltage range V~ range, and connect the test pen to the power supply or load to be tested.
3. When measuring AC voltage, there is no polarity display.
4. Whether measuring AC or DC voltage, pay attention to personal safety and do not touch the metal part of the test pen casually.
Take measuring AC 220V as an example: when measuring, turn the switch to the required voltage gear (when measuring AC 220V, the switch should be turned to AC 750V).
When measuring, the test pen should be connected to the circuit under test in parallel. If you don't know the range of the voltage to be measured, you can use a larger limit test to measure the approximate value, and then go to the corresponding limit to measure.
2. Operation Tips
1. Select the AC voltage gear as the gear. When the voltage range is unknown, it should be selected from the maximum range.
2. The meter should be connected in parallel at both ends of the circuit or component under test.
3. Measurement steps of AC voltage
1. Turn on the power switch of the digital multimeter, and rotate the multimeter gear to the AC voltage gear 750V range.
2. Turn on the power switch in the circuit.
3. Measure the voltage between points 1-2, record the reading, the voltage value is measured as: 220V.
4. Rotate the multimeter gear to the AC voltage gear 20V range, measure the voltages between points 3-4, 4-5, and 6-7 respectively, and record the readings.
(1) The measured voltage between points 3-4 is: 10V.
(2) The measured voltage between points 4-5 is: 10V.
(3) The measured voltage between points 6-7 is: 6.2V.
4. Matters needing attention
1. If you do not know the voltage range to be measured. Set the function switch to the maximum range and gradually decrease it.
2. If the display only shows "1.", it means that the range is too small, and the function switch should be set to a higher range.
3. "" means do not measure voltages higher than 1000V, it is possible to display higher voltage values, but there is a danger of damaging the internal circuit.
4. When measuring high voltage, pay special attention to avoid electric shock.
How does a multimeter measure the zero line
1. Switch the multimeter to the AC gear, I am setting the AC 750V gear, if you want to be more intuitive, you can switch to the smaller AC voltage gear. It depends!
Leave the black test lead in the air (just put it aside), and insert the red test lead into the socket to be tested. The hole with the larger reading is the live wire. It can be seen that the reading displayed when the red test lead is placed in the upper socket is "4".
2. Then put the red test lead into the socket below and try again. You can see that the reading this time is "17", which is obviously larger than the last measured number! It means that this hole is the live wire!
3. Next, use a test pen to verify whether the test results are accurate! Insert the test pen into the hole where the multimeter has a large reading. You can see that the neon tube glows, indicating that it is a live wire!
4. Use a test pen to test the socket above, and you can see that the neon tube does not emit light. Description is the zero line
5. Through the above tests, it can be seen that it is feasible to use a multimeter to distinguish the zero line!
