Why is true effective value so important for clamp meters?
When choosing a caliper, the most common question often heard is "accuracy" and "precision". There are many factors that affect the accuracy of the caliper, including design/workmanship, bandwidth, frequency response, and whether a suitable range is selected. However, one of the most important factors among all of these is true effective value measurement, especially for industrial users with a wide variety of electrical equipment and complex electrical environments.
The non true effective value, also known as the average response instrument, is mainly used for measuring the sine wave of standard power frequency. The common implementation principle is to convert the arithmetic mean reading x1.1 into the 'effective value' reading of a sine wave. In environments with relatively simple electrification, this is completely fine, such as building property management.
In a wider industrial environment, especially with the increasing use of frequency converters, rectifiers, inverters, and other equipment, the actual waveforms are becoming more diverse, and even introducing more and more high-frequency noise. Therefore, in order to accurately measure, true effective value has become one of the most important factors.
When it comes to noise or harmonics, another important concept must be mentioned: low-pass filter (LPF). The implication is that only low-frequency current and voltage can be measured, and the high-frequency part will be excluded from calculation. It can be said that only true effective value clamp tables with low-pass filtering are truly valuable 'true effective values'.
