| Erik Malund 12/01/09 12:45 Read: 518 times Mt Airy, Nc USA |
#171359 - already answered Responding to: Richard Erlacher's previous message |
If you know of a current source that doesn't require a regulated voltage, then show us one
http://www.8052.com/forumchat/read/171263 |
| Topic | Author | Date |
| Trouble with a simple project with ULN2803 | Chico Magalhães | 10/06/09 16:38 |
| Start to search step by step | Per Westermark | 10/06/09 17:18 |
| back to breadboard | Chico Magalhães | 10/06/09 17:53 |
| No surprise... | Kai Klaas | 10/06/09 19:40 |
| Thanks Kai | Chico Magalhães | 10/06/09 21:00 |
| In short | Neil Kurzman | 10/06/09 22:17 |
| Then have a look at the datasheet! | Kai Klaas | 10/07/09 10:14 |
| Don't think so | Per Westermark | 10/07/09 11:09 |
| No, Per, the actual reason is... | Kai Klaas | 10/07/09 16:59 |
| 'working' again | Erik Malund | 10/08/09 05:08 |
| But why? | Kai Klaas | 10/08/09 09:39 |
| Lack of knowledge of the unknown | Per Westermark | 10/08/09 12:29 |
| Ah yes | Steve M. Taylor | 10/08/09 13:01 |
| I think people don't just realize how much they do not know. | Andy Neil | 10/08/09 14:17 |
| There is a reason ... | Richard Erlacher | 10/08/09 23:47 |
| why was working with the other microcontroller | Andy Neil | 10/07/09 01:41 |
| Keep in mind it's on a "breadboard" | Richard Erlacher | 10/07/09 14:05 |
| Infinite Improbability Drive? | Andy Neil | 10/08/09 01:01 |
| re: Infinite Improbability Drive | Andy Peters | 10/08/09 11:06 |
| Pah | Steve M. Taylor | 10/08/09 11:36 |
| Vote: Offensive/Flame! | Andy Neil | 10/09/09 00:33 |
| ;-) | Steve M. Taylor | 10/09/09 00:40 |
| Reference for the uninitiated | Andy Neil | 10/09/09 02:49 |
Without pull-up???  | Per Westermark | 10/07/09 02:06 |
| because it was not working, but 'working' | Erik Malund | 10/07/09 07:58 |
| What else is on your board... | Andy Neil | 10/06/09 17:23 |
| It's a transistor array ... not a magic box | Richard Erlacher | 10/07/09 08:35 |
| AGAIN!!! =( | Chico Magalhães | 11/10/09 19:52 |
| What are you connecting to outputs? | Daniel Contarino | 11/11/09 01:09 |
| Yes...! | Kai Klaas | 11/11/09 08:57 |
| new measures with load | Chico Magalhães | 11/11/09 09:37 |
| How? | Kai Klaas | 11/11/09 09:45 |
| Can use an oscilloscope? | Daniel Contarino | 11/11/09 09:55 |
| Laser and oscilloscope | Chico Magalhães | 11/11/09 10:20 |
| Need current control, not voltage control | Per Westermark | 11/11/09 11:26 |
| re Per | Erik Malund | 11/11/09 11:43 |
| Definitely a good way go let out the magic smoke | Per Westermark | 11/11/09 12:03 |
| not even then | Erik Malund | 11/11/09 12:34 |
| The problem is not the laser. | Chico Magalhães | 11/11/09 13:45 |
| Drive the ULN harder. | Per Westermark | 11/11/09 14:22 |
| Factor 10 off? | Per Westermark | 11/11/09 15:55 |
| I guess, you forgot the Ucesat of ULN2803... | Kai Klaas | 11/11/09 19:00 |
| 74HC04 | Chico Magalhães | 11/11/09 20:38 |
| Better to have them.. | Kai Klaas | 11/12/09 08:52 |
| up the garden path | Erik Malund | 11/12/09 12:24 |
| Definitely consider min/max values from datasheet | Per Westermark | 11/12/09 18:15 |
| Nothing more instructive than... | Kai Klaas | 11/12/09 18:50 |
| but he won't | Erik Malund | 11/13/09 07:04 |
| Yes, that's true... | Kai Klaas | 11/13/09 08:06 |
| a better way | Erik Malund | 11/13/09 11:40 |
| Datasheet | Chico Magalhães | 11/13/09 12:44 |
| OH BOY | Erik Malund | 11/13/09 14:23 |
| Logic level MOSFET... | Kai Klaas | 11/13/09 15:11 |
| A new test I made, bizarre... | Chico Magalhães | 11/14/09 00:00 |
| It seems the power supply... | Daniel Contarino | 11/14/09 00:17 |
| Lack of information | Per Westermark | 11/14/09 03:04 |
| yep. It IS very much! | Daniel Contarino | 11/14/09 03:44 |
| Laser and peltier | Chico Magalhães | 11/14/09 07:38 |
| Dont konw wich regulator you use. | Daniel Contarino | 11/14/09 08:12 |
| well... no regulator at all... | Chico Magalhães | 11/14/09 11:09 |
| PC supplies are not very well regulated | Richard Erlacher | 11/23/09 22:35 |
| For 3V you should have a 3V regulator | Per Westermark | 11/14/09 08:23 |
| That's the explanation! | Kai Klaas | 11/14/09 08:56 |
| 3v | Chico Magalhães | 11/14/09 11:20 |
| Minimum load | Per Westermark | 11/14/09 11:40 |
| Supply and 7805 | Chico Magalhães | 11/23/09 15:16 |
| you want help?? | Erik Malund | 11/23/09 16:35 |
| No laser Datasheet | Chico Magalhães | 11/23/09 22:52 |
| then return it and DEMAND one with a datasheet | Erik Malund | 11/24/09 06:28 |
| Already mentioned lack of datasheet | Per Westermark | 11/24/09 06:40 |
| suggested as first step | Erik Malund | 11/24/09 07:11 |
| laser | Chico Magalhães | 11/24/09 07:13 |
| Hard to tell but I think you should mind the voltage | Per Westermark | 11/24/09 07:40 |
| Perhaps you should use an adjustable regulator | Richard Erlacher | 11/23/09 17:27 |
| I do not think so | Erik Malund | 11/23/09 19:36 |
| and how would YOU build a current source? | Richard Erlacher | 11/23/09 22:30 |
| line anyone else - a 'cookbook' design | Erik Malund | 11/24/09 06:29 |
| can you do that without a regulated voltage source? | Richard Erlacher | 11/24/09 07:16 |
| yes | Erik Malund | 11/24/09 08:11 |
| Guys, Chico has a Laser modul, already... | Kai Klaas | 11/24/09 08:52 |
| two possibilities | Erik Malund | 11/24/09 09:15 |
| assumptions are dangerous | Per Westermark | 11/24/09 09:25 |
| But I didn't assume, that it has a good current control! | Kai Klaas | 11/24/09 10:32 |
| Stable is one thing - what voltage is another | Per Westermark | 11/24/09 11:50 |
| If only Chico had sent us a link to his Laser modul... | Kai Klaas | 11/24/09 12:25 |
| probably highly unstable | Erik Malund | 11/24/09 12:54 |
| Yes, and a good linear regulator can supply that! | Richard Erlacher | 11/24/09 22:56 |
| That was my point! | Richard Erlacher | 11/24/09 22:56 |
| we can't know for certain, but ... | Richard Erlacher | 11/25/09 23:52 |
| What is an ST2221 | Richard Erlacher | 11/24/09 22:53 |
| ST2221a != ST2221 | Per Westermark | 11/24/09 23:18 |
| didn't you notice the reference to an earlier post? | Richard Erlacher | 11/24/09 23:32 |
| you will need one of these | Erik Malund | 11/25/09 06:04 |
| Yes, if you have a good, stabile supply without much noise | Richard Erlacher | 11/25/09 23:46 |
| A current source isn't a magic beast | Per Westermark | 11/26/09 02:57 |
| ... but only if ... | Richard Erlacher | 11/26/09 15:59 |
| and I thought this was turkey day | Erik Malund | 11/26/09 18:33 |
| Are you assuming CC has to be passive? | Per Westermark | 11/26/09 18:52 |
| that would be ridiculous | Erik Malund | 11/27/09 06:41 |
| Ask Richard. | Per Westermark | 11/27/09 06:50 |
| other than Richard? | Erik Malund | 11/27/09 07:08 |
| Now define "constant" | Richard Erlacher | 11/27/09 16:22 |
| Consider this ... | Richard Erlacher | 11/28/09 16:02 |
| Of course, it is... | Kai Klaas | 11/28/09 19:30 |
| Current control != Constant Current | Per Westermark | 11/28/09 22:05 |
| irrelevant | Erik Malund | 11/30/09 08:43 |
| Why do you continue in this way, Erik? | Richard Erlacher | 11/30/09 16:30 |
| Minimalistic const current regulator | Per Westermark | 11/30/09 19:23 |
| It's a matter of definition | Richard Erlacher | 12/01/09 09:07 |
| Ideal constant current source... | Kai Klaas | 12/01/09 09:30 |
| That's where this whole thing began ... | Richard Erlacher | 12/01/09 17:28 |
| Don't jump around wildly when cornered | Per Westermark | 12/01/09 23:43 |
| That's not what was said | Richard Erlacher | 12/03/09 14:26 |
| That's why we should avoid to offend each other... | Kai Klaas | 12/03/09 15:00 |
| Still trying to smash in open doors | Per Westermark | 12/04/09 01:44 |
| The world is flat! | Andy Neil | 12/04/09 02:11 |
| VERY "poor choice of wording" | Erik Malund | 12/04/09 16:17 |
| It wasn't MY wording to which I referred, Erik | Richard Erlacher | 12/05/09 09:21 |
| Memory lapse? | Per Westermark | 12/05/09 14:49 |
| You missed the point, Per | Richard Erlacher | 12/05/09 22:16 |
| I didn't even bother .... | Erik Malund | 12/05/09 18:06 |
| Why, then did you mention it? | Richard Erlacher | 12/05/09 22:18 |
| Lots of ridiculous claims later... | Per Westermark | 12/06/09 04:00 |
| ABSOLUTELY NOT | Erik Malund | 12/06/09 06:20 |
| Cunning ? | Steve M. Taylor | 12/06/09 14:14 |
| Perhaps, but ... | Richard Erlacher | 12/07/09 10:56 |
| What definition? CC/CV both have line regulation tolerances | Per Westermark | 12/01/09 09:56 |
| same old, same old, same old | Erik Malund | 12/01/09 12:48 |
| There you go again ... waving your hands ... | Richard Erlacher | 12/01/09 17:34 |
| already answered | Erik Malund | 12/01/09 12:45 |
| is that what you think? | Richard Erlacher | 12/01/09 17:47 |
| language, language, language | Erik Malund | 12/02/09 14:42 |
| a rose by any other name ... | Richard Erlacher | 12/03/09 13:44 |
| nearly any linear regulator can do that | Richard Erlacher | 11/27/09 14:19 |
| Yes, indeed | Richard Erlacher | 11/27/09 12:53 |
| confound it!!! | Erik Malund | 11/27/09 14:21 |
| Will an AC supply be adequate for you? | Richard Erlacher | 11/27/09 16:21 |
| that does not deserve an answer | Erik Malund | 11/27/09 16:37 |
| If not, then show us what is adequate! | Richard Erlacher | 11/27/09 16:53 |
| Now see here ... | Richard Erlacher | 11/27/09 16:46 |
| Not according to the datasheet I have ... | Richard Erlacher | 11/27/09 16:29 |
| of course it does | Erik Malund | 11/27/09 16:40 |
| So what does that schematic mean? | Richard Erlacher | 11/27/09 17:09 |
| re your babble about a constant supply voltage | Erik Malund | 11/27/09 17:21 |
| If that were the case ... | Richard Erlacher | 12/02/09 19:30 |
| Time to return to earth. | Per Westermark | 12/03/09 00:59 |
| What are you trying to prove? | Richard Erlacher | 12/03/09 14:13 |
| Perhaps, but one with no supply? | Richard Erlacher | 11/27/09 16:26 |
| NOBODY, NOBODY can make this work .... | Erik Malund | 11/14/09 11:53 |
| How about LM317? Look it up! | Richard Erlacher | 11/14/09 12:46 |
| As I said here... | Kai Klaas | 11/14/09 16:04 |
| Just a minute, Chico ... | Richard Erlacher | 11/11/09 23:05 |
| Double check | Daniel Contarino | 11/11/09 11:34 |
| I see no pullups | Erik Malund | 11/11/09 06:23 |
| "The commom of the resistor array is connected to +5v" | Chico Magalhães | 11/11/09 08:55 |
| Not what I mean! | Daniel Contarino | 11/11/09 09:17 |
| He probably needs pullups on both inputs and outputs. | Richard Erlacher | 11/13/09 12:55 |
| be specific!!! | Erik Malund | 11/13/09 14:27 |
| Now I understand ... | Richard Erlacher | 11/13/09 17:33 |
| au contraire | Erik Malund | 11/13/09 19:10 |
| Gate Threshold Voltage, what is? | Chico Magalhães | 11/26/09 05:54 |
| Did you really try Google? | Per Westermark | 11/26/09 06:04 |
| I tried google... | Chico Magalhães | 11/26/09 06:38 |
| Vgs > Vgs(th)! | Kai Klaas | 11/26/09 08:46 |
| I GAVE UP! | Chico Magalhães | 01/12/10 22:55 |
| Don't give up! | Andy Neil | 01/13/10 01:30 |
| Yes, don't give up! | Kai Klaas | 01/13/10 07:41 |
DONT GIVE UP, did you try ... | Erik Malund | 01/13/10 08:17 |