How to calculate voltage measurements on an analog multimeter
Analog multimeters generally have 4 to 5 scales, including resistance scale, voltage scale, current scale, and decibel scale. There is also a special scale for AC 1OV. This scale can be read directly at the 1OV scale, and the voltage scale is There are AC and DC scales, and some tables also have AC current ranges, which are listed in DC voltage ranges. For example, the DC voltage range (MF-10 type meter) has 1V2.5V10∨50∨100V250V500V, and the DC voltage range scale has O-5O. 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 become the actual value. When it is 10V, it is multiplied by 0.2. When it is 100V, it is multiplied by 2. That is, the full scale is 1v, 10V and 100V. When the range switch is set to 2.5V and 250, the indicated value is multiplied by 0.05 and 5 respectively to obtain the actual value. When the range switch is set to 500, just multiply it by 10. The same applies to the AC voltage range.
When you measure voltage, you will choose different gears to measure. When the meter needle stabilizes at a certain value and stops swinging, the value you read multiplied by the multiple of the gear you use is the actual voltage value measured by the multimeter.
A multimeter can not only measure voltage but also leakage. There are two methods for measuring 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 equipment is leaking with the resistance method? First, turn off the power of the electrical equipment, use a multimeter, and first adjust the multimeter to the resistance buzzer level. One test lead of the multimeter is placed on the casing of the electrical equipment, and the other test lead is placed on the live wire and neutral wire respectively. If the multimeter makes a sound, it means that the electrical equipment has serious leakage, and the location of the leakage must be checked.
If the multimeter does not make any sound, 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 means there is leakage, and if it is higher than 0.38M ohm, it means there is no leakage.
To measure the leakage of electrical equipment with the voltage method, turn on the switch of the electrical equipment and turn the multimeter to the AC 700V gear (the gears of each multimeter may be different, so adjust to the maximum current gear). The red color of the multimeter The test lead is placed on the casing of the electrical equipment, and the black test lead is placed on the zero line. The multimeter shows voltage, indicating that the electrical equipment is leaking electricity. The multimeter shows that the voltage is zero, indicating that there is no leakage of electricity.
The voltage method for measuring leakage has certain limitations. It can only measure live wire leakage, but not neutral wire leakage. 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.
