The Model DA30A RMS Voltermeter measures the actual root-means-square (RMS) value of AC voltages between 100 microvolts and 300 volts. Frequency range is from 10Hz to 10MHz. Full scale mesurements of nonsinusoidal waveforms with crest factors (ratio of peak voltage to RMS voltage) of 10 can be made.The Model DA30A provides a dc output which is proportional to the front meter reading. By using this voltage to drive auxiliary equipment, the Model DA30A functions as an RMS ac-to-dc converter. It can drive dc digital voltmeter to rise measurement precision. So it can be used in factory, laboratory and science unit.