Multimeters are divided into analog multimeters and digital multimeters according to the structure of meter and method of measurement.Multimeters are a kind of electric parameter measuring instrument, and also tools that are applicable to all electric occasions.In comparison with analog multimeters, digital multimeters have the merits of higher measurement accuracy, higher input impedance, and direct reading, etc.Common multimeters generally have three basic functions: current, voltage and resistance measurement. Apart from these functions, multimeters are evolving towards multiple functions now. Many multimeters have extended functions such as measurement of capacitance, frequency, duty cycle, temperature, diode, and continuity, etc.Multimeters are mainly divided into two categories: analog multimeters and digital multimeters.
Just as their names imply, analog multimeters display the result of a measurement via the degree of analog deflection, while digital multimeters transfer the result of a measurement to an electrical signal, and presents it on the screen in the form of numbers. In the past, the multimeter market was dominated by analog ones, but since technology is making progress and the cost of digital multimeters is lowering, digital multimeters are gradually predominating the market in place of analog multimeters. By contrast,
- Digital multimeters present more intuitive and more accurate readings and are convenient for quantitative measurement; once a parameter to be measured is input, the pointer of an analog multimeter will deviate; a user cannot but estimate its reading, which might be less accurate compared to numbers. Thus, analog multimeters are more applicable to observational measurement.
- An analog multimeter will make an immediate response to a parameter that has been input, and is able to detect continuous changes of circuit; while on the part of a digital multimeter, three or four samplings will be required in a second; it will take some time to respond and cannot monitor circuit changes in a timely way.
- Thanks to a high input impedance of digital multimeters, it will exert little effect on a circuit at the time of measurement; but the high input impedance will interfere with the measurement of the direct voltage that is mixed with impulse wave, and have an influence on the accuracy of measurement. analog multimeters have low input impedance, which will have an effect on the working condition of the circuit during measurement but will not be prone to the interference that digital multimeters encounter.