Common DC voltmeter measurement circuit diagram

Many electrical parameters in electrical quantity measurement, including current, power, signal modulation fluctuation, equipment sensitivity, etc., can be regarded as derived quantities of voltage and their values ​​can be obtained through voltage measurement.

Voltage measurement can be divided into two methods: analog and digital. The former uses an analog voltmeter to display the measurement results, while the latter uses a digital voltmeter, that is, a digital display to display the measurement results. The only difference between the two is that the latter replaces the analog display meter part of the former with an A/D converter and a digital display. The working principle of the front-end part of the two is basically the same. The advantages of analog voltmeters are simple structure, low price, and wide measurement frequency range; the disadvantages are low accuracy and resolution, and it is not convenient to form an automatic test system with a computer. Digital voltmeters are just the opposite.

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Figure 1 Common DC voltmeter circuit