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Kai Klaas
11/18/13 16:08
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Msg Score: +2
 +1 Good Answer/Helpful
 +1 Informative
#190151 - Bourns says: "yes."
Responding to: Raghunathan's previous message
Raghunathan said:
Considering a potentiometer with the same rating - does the maximum current apply to both the winding as well as the wiper contact ?

Dear Raghunathan,

decades ago Bourns has pubished a trimmer handbook in which they give an answer to your question: If the wiper maximum current rating isn't specified in the datasheet, the maximum current through the wiper is the same as what the trimmer element can handle at maximum power dissipation, provided it doesn't exceed 100mA. So your wiper can safely handle about 30mA.

By the way, even a minimum current across the wiper is necessary to guarantee a proper wiper performance: More than 25uA, better more than 100uA. This is often overlooked, when connecting the wiper of a trimmer directly to the input of an FET-OPamp...

Kai Klaas

List of 15 messages in thread
Power rating of potentiometers      Raghunathan      11/14/13 21:24      
   Not the point      Andy Neil      11/15/13 11:47      
      show me such        Jan Waclawek      11/16/13 13:48      
         (was) incorrect      Erik Malund      11/16/13 18:02      
            not your average "pot"      Andy Neil      11/17/13 07:40      
         Specs that are not normally told..      Raghunathan      11/17/13 03:37      
            power      Joseph Hebert      11/17/13 04:10      
            test bench vs field design       Jim Granville      11/17/13 12:13      
         That was kind of my point      Andy Neil      11/17/13 07:50      
   pot limits      Joseph Hebert      11/17/13 04:00      
      While I don't disagree ... there are different failure modes        Richard Erlacher      11/17/13 14:50      
   Bourns says: "yes."        Kai Klaas      11/18/13 16:08      
      Tesla says: no      Jan Waclawek      11/19/13 14:11      
      cermet or wirewound      Jan Waclawek      11/20/13 01:02      
         No big difference, if it all      Kai Klaas      11/23/13 06:10      

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