Diagram of ordinary DC voltmeter measurement circuit

Many electrical parameters in electricity measurement, including current, power, signal modulation amplitude, equipment sensitivity, etc., can be regarded as derivatives of voltage, and their values ​​are 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, and the latter uses a digital voltmeter to display the measurement results on a digital display. 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 inconvenient to form an automatic test system with a computer. A digital voltmeter is just the opposite.

(1)

Figure 1 Ordinary DC voltmeter circuit