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Erik Malund
12/16/05 06:39
Read: 754 times
Mt Airy, Nc
USA


 
#105357 - dont do it
Responding to: Suresh R's previous message
I need to connect 7805 to a 35VDC rectified o/p.
For this I need to produce a voltage drop of 20 V before giving it to 7805.
can any one suggest me suitable means to do it.

dont do it, 35V is on the edge of what the 7805 can tolerate and the drop resistor is a waste. Use a small switcher such as the PT6302 it can tolerate a larger Vin and need no drop resistor. (I have used more than 10.000 PT6302s and not lost one)

Erik

http://focus.ti.com/docs/prod...t6302.html

List of 33 messages in thread
TopicAuthorDate
Add on card programming      Suresh R      12/07/05 03:11      
   please clarify      Jan Waclawek      12/07/05 03:35      
      RE: please clarify      Suresh R      12/07/05 04:35      
         (E)ISA addressing      Jan Waclawek      12/07/05 04:48      
            IOW and IOR      Suresh R      12/08/05 04:52      
               not explicitly      Jan Waclawek      12/08/05 06:02      
                  IRQ in EISA slot      Suresh R      12/09/05 01:05      
                     interrupt      Jan Waclawek      12/09/05 02:21      
                        QBASIC programming      Valentin Angelovski      12/09/05 04:53      
                           reply      Suresh R      12/10/05 04:10      
                              DIP Switch Address Setting in EISA card      Suresh R      12/12/05 03:10      
                                 DIP switches...      Valentin Angelovski      12/12/05 03:55      
                                    card design enclosed      Suresh R      12/13/05 02:10      
                                       comparator      Jan Waclawek      12/13/05 02:30      
                           QBASIC live and well.      Charles Bannister      12/12/05 11:12      
                              NT - not quite      Andy Neil      12/12/05 16:16      
                                 timing in Win?      Jan Waclawek      12/12/05 16:21      
                              QBasic Lives!!!      Valentin Angelovski      12/12/05 17:24      
   refer to 'Barry B Brey'      Abhishek Singh      12/07/05 07:39      
   EISA Bus interfacing      Valentin Angelovski      12/08/05 15:54      
      beware if (E)ISA bus books      Erik Malund      12/09/05 08:11      
   Try this?      Andy Neil      12/14/05 15:16      
      Power resistor selection      Suresh R      12/16/05 04:52      
         dont do it      Erik Malund      12/16/05 06:39      
            LM317 is an option      Abhishek Singh      12/16/05 07:46      
               Wasteful!      Andy Neil      12/16/05 09:34      
                  if op can...........      Abhishek Singh      12/17/05 07:16      
                     Power!      Andy Neil      12/17/05 08:27      
         basic Ohm's law      Andy Neil      12/16/05 09:40      
            Trouble shoot      Suresh R      12/19/05 05:13      
               heating      Terry Lingle      12/19/05 07:08      
                  Reply : Heating      Suresh R      12/20/05 04:29      
                     if you refer to D4 then      Erik Malund      12/20/05 06:12      

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