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???
01/17/05 13:55
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#85090 - universal solution
Responding to: ???'s previous message
1. In a mains operated unit, whether the output is referenced to mains ground or floating ( would a simple ohmic value check between the -ve terminal of the output and the PE pin suffice ? )

2. Source impedance. This is the real problem- you have no idea unless the manufacturer specifies - is there any way to find this out ?


Raghu,
I did, when such was on my table, always use a high impedance (>1M) differential input circuit with a high CMRR.
The high input impedance will, in almost all cases, make the source impedance unimportant ( with "unknown inmput" you need a gain adjustment anyhow).
The high CMRR makes 1) irrelevant.

The above does not adhere to my basic philosophy, but after many futile attempts to get complete specs on industrial sensors, that was my solution.

Erik

List of 28 messages in thread
TopicAuthorDate
Source Impedance            01/01/70 00:00      
   Re            01/01/70 00:00      
      Impedance measurement            01/01/70 00:00      
      Being more concrete            01/01/70 00:00      
         What about my Rogowski Coils.            01/01/70 00:00      
            Already answered in detail!            01/01/70 00:00      
               Re: ' Detailed Answer'            01/01/70 00:00      
                  Bridge            01/01/70 00:00      
                     What Bridge,            01/01/70 00:00      
                        bridge            01/01/70 00:00      
                           and ...            01/01/70 00:00      
                  Using an OPamp            01/01/70 00:00      
                     Using OpAmp            01/01/70 00:00      
                        Some disadvantages            01/01/70 00:00      
                           Correct formula            01/01/70 00:00      
                              Thanks Kai,            01/01/70 00:00      
                        LCR meters quite common            01/01/70 00:00      
                           Re: LCR Meter.            01/01/70 00:00      
                     Resonant coupling...            01/01/70 00:00      
                        Sorry!            01/01/70 00:00      
   Go with the rule of Thumb            01/01/70 00:00      
      No more than about 10kOhm            01/01/70 00:00      
         Line drops            01/01/70 00:00      
            Thicker cable            01/01/70 00:00      
               Freq domain analysis            01/01/70 00:00      
   re: Source Impedance and driver types            01/01/70 00:00      
   universal solution            01/01/70 00:00      
   Thanks ....            01/01/70 00:00      

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