How to select a multimeter depends on your specific application.
If the questioner purchases a multimeter with low usage frequency and only occasionally uses it at home to measure AC220V voltage or battery voltage, as well as the continuity of the circuit, then spend 30-40 yuan to buy a regular 3/? A digital multimeter is sufficient.
Ordinary digital multimeters such as DT830 and UT33D can measure AC/DC voltage, current, and resistance, and come with diode and buzzer settings, which are sufficient for general measurement and simple maintenance at home.
By the way, when purchasing this type of multimeter, don't expect it to be cheap. Instead, buy those digital multimeters that cost over ten yuan. These cheap ones have poor reliability and save on internal components.
The AC voltage range of a good DT830 multimeter uses a TL062 operational amplifier connected to a precision rectifier circuit, which can accurately measure low-frequency AC voltages in the millivolt range. However, those multimeters of the same model that cost more than ten yuan omit the TL062 operational amplifier;
The 1N4007 diode rectifier is used, so its AC voltage range can only measure AC voltages above 1V, and there is a large error in measuring millivolt level AC voltages.
How to choose a multimeter depends on your own usage
Multi functional digital multimeter.
If the questioner is engaged in electrical repair and needs to measure multiple electrical parameters, it is recommended to purchase a fully functional digital multimeter. This type of multimeter is available in prices ranging from 70-80 to hundreds of yuan.
Most digital multimeters in this price range come with capacitor, frequency, and transistor beta settings, which can measure capacitors of 2000~20000 μ F and frequencies of 2~20MHz. Some digital multimeters can also measure conductivity, duty cycle, temperature, and inductance.
VC9808+digital multimeter, capable of measuring frequencies up to 20MHz in the frequency range and up to 2000M Ω in the resistance range, with a temperature measurement range of -20~1000 ℃, and can also measure inductance;
It can measure a maximum inductance of 20H and is very convenient for measuring various types of inductive coils.
How to choose a multimeter depends on your own usage
True RMS digital multimeter.
A regular digital multimeter can only measure low-frequency sine wave AC voltage between 40-400Hz. If the waveform of the measured AC voltage is a triangular wave, rectangular wave, or other waveform, the reading error will be significant.
If the questioner needs to measure non sinusoidal AC voltage, it is recommended to purchase a true RMS digital multimeter, which is usually labeled "True RMS" on the panel;
Internally, AD736 and other true effective value measurement ICs are used to measure AC voltage, which can accurately measure AC voltage of any waveform and is independent of waveform distortion.
