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???
03/12/12 14:43
Modified:
  03/12/12 14:45
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 		 #186606 - What accuracy do you need?
Responding to: ???'s previous message
Yagnesh Mehta said:
Hi,

For Example:
Current Transformer(100:1A)
Burdan Resister: 0.5 OHM
Output 0.5 V

0->100A => 0->1A => 0->0.5v

And waveform is not Sinusoidal its chopped (SCR waveform)

"a precision rectifier (usually involving an OPamp or two) will not distort anything"
i know Precision rectifier will not distort waveform but performance vice it will measure SCR waveform.
is there any limitation of presition rectification?


The limitation of the precision rectifier is the bandwidth and the offset of the opamp.
The bandwidth limits the frequency of the input signal it can handle.
The offset limits the smallest signal you can measure.

What accuracy do you need?
Don't go overboard, there is limit to the accuracy of a C.T. for chopped waveforms due to freq components and P.T. at such high voltages.
BTW is this a control for a Xray machine?

List of 66 messages in thread
TopicAuthorDate
Sine wave detection on microcontroller            01/01/70 00:00      
   Detect or measure?            01/01/70 00:00      
      not detection, measurement of sine wave signal            01/01/70 00:00      
         What are you measuring?            01/01/70 00:00      
            RMS and Average - 1st Priority            01/01/70 00:00      
               415 v            01/01/70 00:00      
                  I have to do using MCU            01/01/70 00:00      
                     Start simple            01/01/70 00:00      
                        if time is major isssue than.....            01/01/70 00:00      
                           People responding to specific questions            01/01/70 00:00      
                              Same Technique....            01/01/70 00:00      
                                 RMS            01/01/70 00:00      
                                    Sorry for my laziness            01/01/70 00:00      
                                 So what have you done?            01/01/70 00:00      
                                    Require more work...            01/01/70 00:00      
                                    Working on that            01/01/70 00:00      
                                       options, options            01/01/70 00:00      
   Help me            01/01/70 00:00      
      Okay            01/01/70 00:00      
         Are many threads available            01/01/70 00:00      
      when you save a char ...            01/01/70 00:00      
      Why don't you specify your problem COMPLETELY?            01/01/70 00:00      
         Already specify it            01/01/70 00:00      
            there are some details?            01/01/70 00:00      
               comparisions            01/01/70 00:00      
                  How are you calculating your needed sample rate?            01/01/70 00:00      
                     start with simple one....            01/01/70 00:00      
                        You do know sin(90+angle)? Or 2-log computations?            01/01/70 00:00      
                           ADC resolution............            01/01/70 00:00      
                              impossible or wrong            01/01/70 00:00      
                              double post, ignore            01/01/70 00:00      
                  Precision Rectify:            01/01/70 00:00      
                     SCR Chopped Wave            01/01/70 00:00      
                        What accuracy do you need?            01/01/70 00:00      
                           CT accuracy            01/01/70 00:00      
                              the fundamental            01/01/70 00:00      
                              50Hz            01/01/70 00:00      
                              Precision rectifier is suitable for any waveform            01/01/70 00:00      
                                 are u sure??            01/01/70 00:00      
                                    Depends            01/01/70 00:00      
                                    must be severely bandwidth limited            01/01/70 00:00      
                                       Maybe was circuit with top-voltage capacitor            01/01/70 00:00      
                                       Sorry for confusion            01/01/70 00:00      
                                          What accuracy do you need?            01/01/70 00:00      
                                             360/1024            01/01/70 00:00      
                                                Not what he (or me) have asked            01/01/70 00:00      
                                                   you are right....            01/01/70 00:00      
                                                Do you believe you can protect your circuit from noise?            01/01/70 00:00      
                                                   Very Noisy environment            01/01/70 00:00      
                                                      re Very Noisy environment            01/01/70 00:00      
                                                         Some of those rules are showing their age            01/01/70 00:00      
                                                            here we go again            01/01/70 00:00      
                                                               think about this for a minute            01/01/70 00:00      
                                                                  when discussing a FAQ            01/01/70 00:00      
                                                                     Well, when were those cap sizes determined?            01/01/70 00:00      
                                                                        Technology            01/01/70 00:00      
                                                                           Steady state currents do not need decaps            01/01/70 00:00      
                                                                              Often low capacitance so limited charge. But remember load.            01/01/70 00:00      
                                                                        fixations            01/01/70 00:00      
                                                                           Nothing. has been proven yet.            01/01/70 00:00      
                                                                              once more for the peanut gallery            01/01/70 00:00      
                                                                                 Where you sit determines what you see ...            01/01/70 00:00      
                                                                                    Off-topic            01/01/70 00:00      
                                                                                       difficult when ...            01/01/70 00:00      
                                                                                       Yes ... I don't know how we got here either            01/01/70 00:00      
                                                                                          i do            01/01/70 00:00      

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