measurement range

Choose a suitable voltmeter based on the actual AC voltage range that needs to be measured. Generally speaking, the range of the selected voltmeter should be slightly larger than the maximum value of the measured voltage to ensure measurement accuracy and safety. For example, to measure the voltage of a household circuit (usually 220V), an AC voltmeter with a range of 0300V or 0500V can be selected.

accuracy class

The precision level reflects the accuracy of the voltmeter measurement results. Common accuracy levels include 0.1, 0.2, 0.5, 1.0, 1.5, etc. The higher the accuracy level, the smaller the measurement error, but the price is relatively high. For general industrial measurement and laboratory applications, accuracy levels of 0.5 and 1.0 are usually sufficient to meet the requirements; For high-precision metrological testing and scientific research experiments, it is necessary to choose a high-precision voltmeter with a rating of 0.1 or 0.2.

input impedance

The input impedance of the AC voltmeter should be as high as possible to reduce the impact on the tested circuit. High input impedance can prevent the voltmeter from drawing too much current from the tested circuit, thereby ensuring the accuracy of the measurement results. Generally speaking, for low-frequency AC voltage measurement, the input impedance should not be less than 1M Ω; for high-frequency AC voltage measurement, the input impedance should be higher, usually requiring several tens of M Ω or more.

frequency response

Different AC voltmeters have different response characteristics to AC signals of different frequencies. If the frequency range of the AC voltage to be measured is wide, it is necessary to choose a voltmeter with good frequency response. A typical AC voltmeter can meet the power frequency measurement requirements of 50Hz and 1kHz; If it is necessary to measure AC voltage within the audio range (20Hz, 20kHz), a voltmeter with audio frequency response characteristics needs to be selected; For higher frequency AC voltage measurements, such as measuring radio frequency (RF) signals, specialized RF voltmeters or oscilloscopes are required.

display mode

There are two display modes for AC voltmeters: pointer type and digital type. A pointer type voltmeter has the characteristics of intuitive and continuous display, which can quickly reflect the trend of voltage changes, but the reading accuracy is relatively low; Digital voltmeters have the advantages of accurate reading, high precision, strong anti-interference ability, and can directly display the measured values, making it convenient to read and record, but the price is relatively high. Suitable display modes can be selected based on actual usage needs and personal preferences.

Features

According to specific application scenarios, other functional characteristics of the voltmeter can also be considered. For example, whether it has an automatic range switching function, which can enable the voltmeter to automatically select the appropriate range when measuring voltages of different sizes, improving the convenience and efficiency of measurement; Whether it has data recording and storage functions to facilitate the storage and subsequent analysis of measurement data; Does it have communication interfaces such as RS232 and USB to connect with computers or other devices for remote control and data transmission.

price

The price of an AC voltmeter varies depending on factors such as brand, accuracy level, and functional characteristics. When making a purchase, one should consider both their budget and actual needs comprehensively. Don't blindly pursue high priced products, and don't choose low-priced products that cannot meet quality and performance requirements in order to save costs. Generally speaking, the price of a regular pointer type AC voltmeter is relatively low, ranging from tens to hundreds of yuan; High precision digital AC voltmeters are more expensive, and may cost thousands or even tens of thousands of yuan.