Hi <br>there is a cool IC that perfoms RMS to DC conversion. It's from MAXIM ... I don't remember the right number but i believed it was MAX687 or something.... try it at <A HREF="
There is a special case of RMS determination which might be worth mentioning.<br><br>If we have a square wave of zero volts to a unipolar peak of "E" volts (typical of much logic circuitry with zero and +5 volts) and some particular duty cycle, the average value of that waveform is E average which equals E times that duty cycle.<br><br>Then, having obtained the average, the root mean square voltage, call it E rms, equals E average divided by the square root of that duty cycle.<br><br>The average value is easily measured with any DVM and an RC low-pass filter. From that measurement, the RMS value can be calculated.<br><br>This appeared in Electronic Design for October 14, 1993 in the Ideas For Design section.<br><br>John Dunn<br>Ambertec, Inc.
ref to intersil or teledyne data book for icl 7107 31/2 digit dpm application notes where fully operational true rms ckt using opamp is detailed , if you ere not able to get on your oen mail me your e mail id for the circuit
