The basic working principle of digital voltmeter measurement

A digital voltmeter is an instrument used to measure voltage. It is based on some basic working principles to achieve accuracy and reliability in measurement. This article will detail the basic working principles of a digital voltmeter and the role it plays in measuring voltage.

The basic components of a digital voltmeter include an input circuit, establishing a reference voltage, an amplifier circuit, an analog-to-digital converter (ADC), a digital processing circuit, and a digital display section. These components are described in detail below.

First, the input circuit is one of the key components of a digital voltmeter. It is mainly responsible for receiving the measured voltage signal and converting it into a voltage signal that can be processed by the amplifier. The input circuit usually includes a resistor network to limit the input current to prevent it from affecting the circuit under test. In addition, the input circuit should also have a high input impedance to ensure that its effect on the circuit under test is as small as possible.

Next, a reference voltage is established to determine the datum for the measured voltage. To ensure accurate and reliable measurements, digital voltmeters require a reliable and stable reference voltage. For this purpose, an internal voltage regulator is usually used to generate a stable reference voltage. This reference voltage can be a fixed value or adjustable to accommodate measurements of varying accuracy and range.

Third, the amplifier circuit serves to amplify the input voltage signal to a suitable range that can be processed by an analog-to-digital converter (ADC). Amplifier circuits usually use op-amps (operational amplifiers) as the main component to achieve voltage amplification. Operational amplifiers are characterized by high gain and low distortion, and are capable of amplifying the input signal to an appropriate level for subsequent processing.

Fourthly, analog-to-digital converter (ADC) is used to convert the analog voltage signal into digital form. In a digital voltmeter, the ADC is usually a successive approximation modulation (SAR) or integral ADC. successive approximation modulation is a high-precision analog-to-digital conversion technique that progressively approximates the digitized value of the input signal by comparing the magnitude of the input signal to a reference voltage.

Fifth, the digital processing circuit is responsible for processing and correcting the digitized signal. The digital processing circuit usually includes a series of calibration and filtering operations to ensure the accuracy and stability of the measurement. Among other things, the calibration operation corrects the zero and gain errors of the digital voltmeter to improve the measurement accuracy. The filtering operation reduces the interference of noise and spurious signals to improve the reliability of the measurement results.

Finally, the digital display section is designed to convert the processed digital signal into a form that is easy to understand and read. The digital display section usually uses digital tubes or liquid crystal displays to show the measurement results. These displays show the numerical values and units of the measurement results so that the user can visualize and understand the magnitude of the voltage being measured.

Overall, a digital voltmeter is a precision measuring instrument realized using modern electronic technology. The measured voltage is converted into a voltage signal that can be processed through an input circuit, based on the establishment of a reference voltage, the voltage signal is amplified to an appropriate range through an amplifier circuit, the analog signal is converted into a digital signal through an ADC, followed by calibration and filtering operations through digital processing circuits, and finally, the results of the measurements are presented to the user through a digital display section. These components collaborate with each other to realize the basic working principle of digital voltmeter.