True RMS Multimeter Description
Describe the size of the alternating current quantities are: peak (and peak-peak), the average value, the effective value, the peak is the maximum value; the average value is the alternating current (that is, after rectification) in a cycle of the average; the effective value is also known as the root-mean-square value (a floor of the formula). Effective value: the DC and AC respectively through two identical resistor devices, if they produce equal heat in the same time, then the DC voltage, current as the effective value of this AC. So people generally say that the voltage, current size in no particular statement on the RMS value. There is a certain relationship between the three: the ratio of the rms value and the average value is called the waveform factor KF; the ratio of the peak value and the rms value is called the crest factor KP. For sinusoidal waves, the crest factor KP = root 2 (constant), the waveform factor KF = 2 times the root of the row of 2 points (constant). And for non-sinusoidal waves the values change. Obviously, people are most concerned about the RMS value, but not good measurement, while the average value and peak value is easy to measure, so the ordinary multimeter (including voltmeter, etc.) are indirectly measured by measuring the average value or peak value of the method of measuring the RMS value (according to the sinusoidal relationship). Such as measuring the peak of the table, if the measured size of 10V, the display is 7.07V (RMS) on the line. These two types of tables show the RMS value, but the measurement is a "false" RMS value, it is clear that this type of table to measure the sine wave or more accurate, but the measurement of non-sinusoidal wave is not right. Accurate table, you can directly measure the RMS value (many methods), that is, it shows the RMS value, the measurement is also the RMS value, so this table regardless of the measurement of which waveform results are correct. In order to distinguish between the first two types of meter, so called true RMS.
