I have Delphi 5 and Component Works 3.

[Serafimov]

Can you tell me how to measure the effective value of AC?
Which functions i must use and with what parameters?
It will be indispensible if you can give me some simple example,i prefer coded in Delphi, but nevermind the language:
Visual Basic,C++ or Delphi.

[Jeremiah Cox]

Hello Serafimov,
There are two (2) main steps necessary to determine the RMS voltage of an input signal. First, we will need to acquire the waveform using the AI component of the CW DAQ control. You can find examples of this located at \vb\samples\daq\analog input\. Next we will need to analyze our voltage waveform to determine it's RMS value. The CWStat component of the CW Analysis control provides a handy RMS method "CWStat.RMS(input array)" which returns the RMS value of an input array. We can use this to compute the RMS value of our voltage waveform. Other handy resources to this question can be found by going to our Developer Zone (http://www.ni.com/zone) and searching for AC and RMS. There are many articles and definitions
that discuss related issues (Tips on AC measurements for example) as well as example code (mostly for LabVIEW).

Jeremiah Cox
Applications Engineer
National Instruments
http://www.ni.com/ask