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Joseph Hebert
11/17/13 04:10
Read: 856 times
Okemah, Ok
United States


 
#190146 - power
Responding to: Raghunathan's previous message
Hi Raghunathan,

When the pot is set to zero ohms, you've got 24V/1k = 24 mA. Since all the voltage is dropped across the 1k resistor, it's dissipating a little over half a watt. Essentially zero volts are dropped across the pot, which means it's now dissipating essentially zero watts. The only question left is whether the 24 mA will melt the contacts/leads. You know they can handle 1.5 Watts across 5k ohms, which at 24 Volts is over 60 mA. What is the maximum voltage the potentiometer is rated for? Whatever that Vmax is, you know it can handle at least 1.5W/Vmax amps.

Hope this helps,

Joe

List of 15 messages in thread
TopicAuthorDate
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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