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???
02/23/10 20:03
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#173494 - NTC versus PTC...
Responding to: ???'s previous message
Kiran said:
But as Steve and Andy mentioned, the diagram shows that it is an NTC, whereas shouldn't that be a PTC ?

It's a bit confusing, both NTCs and PTCs are recommended for limiting of inrush currents sometimes. But what you need is definitely a NTC.

Best you study this following link by yourself. Hit on "data sheets" on the right of "NTC inrush current limiters" and you will find many useful information on how it works and how to find out the right part for your application:

http://www.epcos.com/web/gener...le=en.html

The idea of NTC in your application is to limit the inrush current flowing immediately after connecting your power supply to mains. Remember, there is a cap somewhere at the input of your circuitry, which presents a short circuit to mains, when being uncharged. Without the inrush current limiter, components can get damaged or at least the fuse(s) will break.

But make no mistake, the inrush current is still rather high, even with NTC. It's only to blunt the point a bit...

Kai Klaas

List of 26 messages in thread
TopicAuthorDate
Current Rating of Thermistor/Inductor            01/01/70 00:00      
   NTC or PTC ?            01/01/70 00:00      
      Thanks Andy            01/01/70 00:00      
         PTC.            01/01/70 00:00      
            How will a thermistor LIMIT inrush current ?            01/01/70 00:00      
         SCR dI/dt limiting            01/01/70 00:00      
            Magic bit            01/01/70 00:00      
            Rule 8 comes from here...            01/01/70 00:00      
         RE: I never read anything about this            01/01/70 00:00      
         There are many types of "thermistor"            01/01/70 00:00      
   Thanks Steve and Andy            01/01/70 00:00      
      That's probably the safest route            01/01/70 00:00      
   SCK NTC series...            01/01/70 00:00      
      That's probably not a good idea, unless...            01/01/70 00:00      
      Thanks Kai...            01/01/70 00:00      
         No, you have it exactly the wrong way around!            01/01/70 00:00      
            Would any other NTC do the job..?            01/01/70 00:00      
            Hint: cause of "inrush"            01/01/70 00:00      
               The great White light NOW struck me !!!            01/01/70 00:00      
         NTC versus PTC...            01/01/70 00:00      
            NTC or PTC?            01/01/70 00:00      
               Or by other words...            01/01/70 00:00      
                  Is that really true?            01/01/70 00:00      
                     What I meant...            01/01/70 00:00      
                        It's all about conserving energy            01/01/70 00:00      
   An informative link for In-rush current            01/01/70 00:00      

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