Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
Terry Lingle
03/24/06 07:06
Read: 1008 times
Clearwater
Canada


 
#112973 - The bulb
Responding to: Suresh R's previous message
The only place anyone will get a specific data sheet is from the actual manufacturer of the part in question. You must ask them for it. If they do not have one them perhaps you can select a higher quality lamp from a company that has and will supply a data sheet.

This is supposed to be a test rig so you need to be able to replace the bulb and be confident that the rig will work as designed. you can only do that if you know that your design will work correctly with bulbs that exibit the full range of data sheet values.

The other option is to buy a box of bulbs ans hand pick them to be certain that they fall within your design parameters. With this option you need to specify how to select morre bulbs for that day down the road when the last preslected bulb fails.

The situation that you describe is covered under the second possible case. With this bulb as a load the actual current flow will be less than the constant current source is intended to provide because the lamp is limiting the available voltage to the source to below that needed for it to operate properly.
Had you looked at the data sheet (were it available to you) you would conclude that this lamp is not suitable in this design. to correct the problem you could either raise the input voltage to ensure that the worst case bulb will leave sufficient voltage available for the constant current source to work correctly or select a different bulb that needs less voltage across it at 200 ma.
Your choice but to make it you do need to have correct information on the components that you chose to work with.
Terry



List of 57 messages in thread
TopicAuthorDate
inrush current + suitable voltage sour      Suresh R      03/04/06 10:14      
   Inrush current of lamp      Kai Klaas      03/04/06 20:47      
      Current inrush      Hal Albach      03/05/06 06:28      
         NTC?      Jan Waclawek      03/05/06 06:45      
            Soft-start      Kai Klaas      03/05/06 08:00      
               8 reed SW parallely + 21.12A / at 12VDC      Suresh R      03/06/06 05:29      
                  Car battery???      Anders Sandström      03/06/06 05:58      
                  inrush current      Terry Lingle      03/06/06 08:20      
                  totally irrelevant      Erik Malund      03/06/06 08:58      
                  No testing needed, standardly      Kai Klaas      03/06/06 19:46      
                     replies      Suresh R      03/07/06 02:05      
                        Reply to "replies"      Kai Klaas      03/07/06 07:29      
                           the difference between "cheap" and "inex      Erik Malund      03/07/06 07:44      
                           current limit resistor      Suresh R      03/07/06 09:17      
                              are you just grasping for straws?      Erik Malund      03/07/06 09:29      
            NTC, yes      Erik Malund      03/06/06 08:54      
               Filaments      Kai Klaas      03/06/06 18:38      
                  In the days of radios for AC and DC      Erik Malund      03/07/06 06:57      
                     Thanks      Kai Klaas      03/07/06 07:03      
            resistor parallel to Switch!      Suresh R      03/11/06 04:29      
               MOSFET, constant current source?      Kai Klaas      03/11/06 07:04      
                  not for my use      Suresh R      03/11/06 09:24      
                     Ok, but...      Kai Klaas      03/11/06 10:00      
                        but i think      Suresh R      03/11/06 10:25      
                           Relays      Kai Klaas      03/11/06 10:51      
                              yes ofcourse      Suresh R      03/11/06 11:46      
                                 here we go again        Erik Malund      03/13/06 06:57      
                                    Even more!!      Kai Klaas      03/13/06 07:14      
                                       werlcome to the club      Erik Malund      03/13/06 07:18      
                                       reply      Suresh R      03/13/06 10:49      
                                          why did you not say so?      Erik Malund      03/13/06 11:15      
                                          You made a fool of us!        Kai Klaas      03/13/06 18:24      
                                             reply      Suresh R      03/14/06 03:39      
                                                That's no fun!      Kai Klaas      03/14/06 07:06      
                                                   Suresh, I hope you had fun      Erik Malund      03/14/06 07:28      
                                                   reply      Suresh R      03/14/06 10:29      
                                                      yeah 6 days later.      Erik Malund      03/14/06 10:52      
                  Hello Kai,      Suresh R      03/16/06 22:03      
                     Look at here      Kai Klaas      03/17/06 10:56      
                        Thank you very much Kai.      Suresh R      03/18/06 07:40      
                           It just strikes me      Erik Malund      03/18/06 10:20      
                              yes you are right      Suresh R      03/18/06 12:32      
                                 Reed switch problems      Hal Albach      03/18/06 19:31      
                                    Current rating?      Kai Klaas      03/20/06 19:39      
                                       I recall long ago something about a "sti      Erik Malund      03/21/06 06:47      
                                       Reed problem      Hal Albach      03/21/06 07:11      
                                          Glueing together      Kai Klaas      03/21/06 07:35      
                                             Reed problems      Hal Albach      03/21/06 09:14      
                                                reed relayrs      Terry Lingle      03/21/06 14:01      
                           power dissipation calculations?      Suresh R      03/19/06 08:12      
                              bulb voltage drop      Terry Lingle      03/19/06 10:01      
                                 Thanks      Suresh R      03/20/06 02:12      
                                 (.2*bulb resistance      Suresh R      03/24/06 05:36      
                                    The bulb      Terry Lingle      03/24/06 07:06      
                              Constant current during inrush moment      Kai Klaas      03/24/06 07:22      
                                 Thanks a lot Kai      Suresh R      03/24/06 10:12      
         Choke would be huge      Kai Klaas      03/05/06 07:28      

Back to Subject List