How to calculate the voltage measurement value on the pointer multimeter
Pointer multimeters generally have 4 to 5 scales, which are the resistance scale scale, the voltage scale scale, the current scale scale scale, the decibel scale scale, and there is also a special scale for AC 10V. There are AC and DC scales, and some meters also have AC current ranges, which are listed in DC voltage ranges. For example, DC voltage ranges (MF-10 type gauges) have 1V2.5V10∨50∨100V250V500V, and DC voltage ranges have O-5O on the scale. Digital, when the range switch is set to 50V, it is direct reading. When the range switch is at 1V, the indicated value is multiplied by 0.02 to be the actual value. When it is 10V, it is multiplied by 0.2. When it is 100V, it is multiplied by 2. When the range switch is set to 2.5V and 250, the indicated value is multiplied by 0.05 and 5 respectively to be the actual value. When the range switch is set to 500, it can be multiplied by 10. The same goes for AC voltage files.
When you measure the voltage, you will choose different gears to measure. When the needle pointer stabilizes at a certain value and does not swing, multiply the value you read by the multiple of the gear you use to get the actual voltage value measured by the multimeter.
How does a multimeter measure leakage current
The multimeter can not only measure the voltage but also the leakage current at the same time. There are two ways to measure leakage, one is the resistance method, and the other is the voltage method. Regardless of the resistance method or the voltage method, the red test lead is inserted into the VΩ hole of the multimeter, and the black test lead is inserted into the COM hole of the multimeter.
How to measure whether an electrical device is leaking by the resistance method, first turn off the power of the electrical device, use a multimeter, and first adjust the position of the multimeter to the beeping position of the resistance. One test lead of the multimeter is placed on the shell of the electrical equipment, and the other test lead is placed on the live wire and the neutral line respectively. If the multimeter makes a sound, it means that the electrical equipment has a serious leakage, and the location of the leakage must be checked.
If the multimeter does not make a sound, it is necessary to increase the resistance level of the multimeter step by step until the resistance value is measured. Generally speaking, if the resistance value is lower than 0.38M ohm, it is leakage, and if it is higher than 0.38M ohm, it is no leakage.
Measure the leakage of electrical equipment by voltage method, turn on the switch of the electrical equipment, and turn the gear of the multimeter to the gear of AC 700V (the gear of each multimeter may be different, adjust to the maximum gear of the current gear), the red of the multimeter The test lead is placed on the shell of the electrical equipment, the black test lead is placed on the zero line, the multimeter displays the voltage, indicating that the electrical equipment is leaking, and the multimeter shows that the voltage is zero, indicating that there is no leakage.
The voltage method has certain limitations in measuring leakage. It can only measure the leakage of the live wire, but not the leakage of the neutral wire. If there are capacitive components in electrical equipment, it will also affect the measurement accuracy of the voltage method, so the voltage method is not recommended.
