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???
05/25/06 13:26
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 		 #117090 - in the olden days, they were called URDO
Responding to: ???'s previous message
I didn't understand how NTC will help. Can you please explain?
in the olden days, they were called URDOX resistors and used in serially powered filamet systems for radios with tubes.

Using a NTC will do the following:
in this example I use a 18V 18 ohms cold, 180 ohms warm lamp and a NTC which is 180 ohms cold and 60 ohms warm.
when the lamp is switched on the NTC will be 180 ohms and the lamp will be 18 ohms, so, you get just about 100mA from your 24V supply. In a few seconds the NTC will self heat and you STILL have about 100mA and the lamp is bright.

SO, instead if a 1A inrush, uou get a 100mA inrush.

Clear as mud or do you understand?

Erik

List of 36 messages in thread
TopicAuthorDate
Cable Capacitance Problem ?            01/01/70 00:00      
   Theorizing? this should be fairly easy t            01/01/70 00:00      
      Yes. Lamp is turned OFF and ON            01/01/70 00:00      
         I take that this is simultaneous to my a            01/01/70 00:00      
      The one-shot is probably a factor            01/01/70 00:00      
         Schematic upload - how to do it?            01/01/70 00:00      
            Here is the link            01/01/70 00:00      
   Lamp is working like PTC            01/01/70 00:00      
      in the olden days, they were called URDO            01/01/70 00:00      
         Thanks for the explanation.            01/01/70 00:00      
            because            01/01/70 00:00      
   I miss the urgently needed bandwidth lim            01/01/70 00:00      
       I agree, the idea was too simplistic            01/01/70 00:00      
         peanuts...            01/01/70 00:00      
            I'd say            01/01/70 00:00      
      Working Solution            01/01/70 00:00      
         I don't think it's solved...            01/01/70 00:00      
            Details            01/01/70 00:00      
               Hello?            01/01/70 00:00      
                  try this, try that, go broke            01/01/70 00:00      
               In many companies, it will get you fired            01/01/70 00:00      
                  expanding            01/01/70 00:00      
                  Just debating            01/01/70 00:00      
                     They're a crutch ...            01/01/70 00:00      
                     so called professionals that believe tha            01/01/70 00:00      
                     Monoflops            01/01/70 00:00      
                        burnt child shy fire            01/01/70 00:00      
                        If you are careful, they might work.            01/01/70 00:00      
                           not very good odds            01/01/70 00:00      
                           Being careful...            01/01/70 00:00      
         not noise supression            01/01/70 00:00      
   does the ULN(can't read the numbers) dri            01/01/70 00:00      
      ULN2003            01/01/70 00:00      
         I did NOT ask for the part number, I ask            01/01/70 00:00      
            By other words...            01/01/70 00:00      
               Books don't say all this.            01/01/70 00:00      

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