How to use the ohm range of a digital multimeter
(1) Before using the multimeter, you should first perform a "mechanical zero adjustment", that is, when there is no electricity being measured, the multimeter pointer should point at the zero voltage or zero current position.
(2) When using the multimeter, do not touch the metal part of the test lead with your hands. This can ensure accurate measurement on the one hand, and personal safety on the other hand.
(3) When measuring a certain amount of electricity, you cannot change gears while measuring, especially when measuring high voltage or large current, you should pay more attention. Otherwise, the multimeter will be damaged. If you need to change gears, you should disconnect the test leads first, and then measure after changing gears.
(4) When using the multimeter, it must be placed horizontally to avoid errors. At the same time, attention should also be paid to avoiding the influence of external magnetic fields on the multimeter.
(5) After using the multimeter, the transfer switch should be placed in the maximum AC voltage range. If it is not used for a long time, the battery inside the multimeter should also be taken out to prevent the battery from corroding other components in the meter.
Extended information:
A multimeter is a magnetoelectric instrument with a rectifier that can measure various electrical parameters such as AC and DC current, voltage and resistance. For each electrical quantity, there are generally several ranges. Also known as multimeter or simply multimeter. The multimeter is composed of a magnetoelectric ammeter (meter head), a measuring circuit and a selector switch.
By changing the selection switch, a variety of electrical parameters can be measured conveniently. The main basis for its circuit calculation is Ohm's law of closed circuits. There are many types of multimeters, and you should choose according to different requirements when using them.
The DC current range of the multimeter is a multi-range DC voltmeter. The voltage range can be expanded by connecting a closed-circuit voltage dividing resistor in parallel with the meter. The DC voltage range of the multimeter is a multi-range DC voltmeter. The voltage range can be expanded by connecting a voltage dividing resistor in series with the meter. Different voltage dividing resistors have different corresponding ranges. The meter head of the multimeter is a magnetoelectric measurement mechanism. It can only pass DC and uses diodes to convert AC into DC, thereby achieving the measurement of AC.
The multimeter's selector switch is a multi-position rotary switch. Used to select measurement items and range. General multimeter measurement items include: "mA"; DC current, "V(-)": DC voltage, "V(~)": AC voltage, "Ω": resistance. Each measurement item is divided into several different Measuring ranges are available for selection.
The display digits of a digital multimeter are usually 3 1/2 digits to 8 1/2 digits. There are two principles for determining the number of display digits of a digital instrument: one is that the number of digits that can display all numbers from 0 to 9 is an integer number; the other is that the value of the fractional digit is based on the highest digit of the maximum displayed value. is the numerator, and the count value when using the full scale is 2000. This shows that the instrument has 3 integer digits, and the numerator of the fractional digit is 1 and the denominator is 2, so it is called 3 1/2 digits, pronounced as "three and a half." ”, its highest bit can only display 0 or 1 (0 is usually not displayed).
The highest digit of a 3 2/3-digit (pronounced "three and two-thirds digit") digital multimeter can only display numbers from 0 to 2, so the maximum displayed value is ±2999. Under the same circumstances, it is 50% higher than the measurement limit of a 3 1/2-digit digital multimeter, which is especially valuable when measuring 380V AC voltage.
