I am a post-degree student in Brazil. I am looking for RMS conversor device or to develop an equipment based on RMS conversor. Please, where can I get it? I tried to contact Fluke and
Linear Technology over a month ago and have had no response. Some people told me RMS conversor is not for sale. Thanks.

Mauricio Vaz

 

Exactly what do you want to do?

If you have any kind of possibility to use software to do the trick then do like this:

square each input sample
calculate the average over the desired time
calculate the square root

RMS_value=sqrt((value1**2+value2**2+value3**3+...+valueN**2)/N)

after all that is what RMS means:
Root of the Mean value of the Squares

If you need this in pure hardware it gets somewhat trickier but you need to do the same anyway.

/Johan Bengtsson

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If you are looking for a discrete device to build an RMS measuring instrument around, have a look at Analog Devices.

They make a number of RMS to DC converter chips. AD536/537 for instance.

Maxim second source some of their range (not surprisingly called MAX536 / MAX537)

I don't have AD's URL to hand but Maxim are www.maxim-ic.com.

Hope this helps

Geoff Moore

Straight Forward Solutions Ltd
Maynooth Road, Prosperous, Naas,
Co.Kildare, Ireland
+353 (0)45 892739
[email protected]

 

Try

Analog Devices Inc. Precision Monolithics Inc. and National Semiconductor. At least one of these will have an RMS to DC converter in chip form.

Curt Wuollet
Wide Open Technologies

 

The original true RMS convertor is a little heating element connected to a temperature sensor, you could make your own!

Seriously thougth, check out Analog Devices, they make both RMS convertors and Analog multiplier type function building blocks.

BTW, most apps nowdays would digitize the data and do it in DSP.