[sdiy] Transistor matching Was: Another satisfied Takuya Katayama Tempco customer.

[Csaba Zvekan]

Not at the moment , sorry? We need  more money for  development  and  
robotics assembly design. :)

On Jul 19, 2008, at 6:39 PM, cheater cheater wrote:

> Hmm, so there's no way to modify this to make it automatic? :)
>
>
> On Sat, Jul 19, 2008 at 5:17 PM, Csaba Zvekan <czvekan at gmail.com>  
> wrote:
>>
>> On Jul 19, 2008, at 5:44 PM, cheater cheater wrote:
>>
>>> Hmm, I assume just testing each transistor on its own and recording
>>> parameters wouldn't be good enough.
>>
>> No
>>>
>>> You really need a circuit of two
>>> transistors, don't you?
>>
>> Yes you pick two random transistors and compare the two with your  
>> dual
>> channel oscilloscope. Superimpose the curve and give them a note  
>> let's say
>> from 1 to 10 . Then you would bag them and take the best matched  
>> ones for
>> your projects.
>> I even have a few extra pre matched bags with labels saying 8.5 or  
>> 9 or
>> something on them . That way next time I don't even have to match  
>> them. It's
>> already done. But it's really fun to do it and easy as well.
>>
>>>
>>>
>>> How would you go about testing each pair? You'd have to have some  
>>> sort
>>> of serving facility to store and serve the parts somehow.
>>>
>>> Best regards,
>>> Damian
>>>
>>>
>>> On Sat, Jul 19, 2008 at 4:19 PM, Csaba Zvekan <czvekan at gmail.com>  
>>> wrote:
>>>>
>>>> Damian,
>>>>
>>>> Thanks Damien, ..lol...Yeah I didn't think of that. Labeling &  
>>>> packaging
>>>> of
>>>> the super matched  transistors . :)
>>>> You will laugh cause I really have some barcode readers laying  
>>>> around for
>>>> a
>>>> couple of years now. I remember scavenging an old CD label / sorter
>>>> factory.
>>>> That's where  I got them from  .Up until now I had no idea what  
>>>> to do
>>>> with
>>>> them. :)
>>>> No, but seriously that transistor project  is awesome and credit  
>>>> goes for
>>>> that wonderful man who designed the thing.
>>>> Also I am nothing compared to these people on the SDIY list. They  
>>>> are the
>>>> real miracle makers . I am just a good copy cat :) and feel like
>>>> information
>>>> and knowledge should be free and shared. Cause at one point it  
>>>> was freely
>>>> shared to me.
>>>>
>>>> Csaba
>>>>
>>>> On Jul 19, 2008, at 3:11 PM, cheater cheater wrote:
>>>>
>>>>> Csaba,
>>>>> I assume it would also have to label each part that's being  
>>>>> matched to
>>>>> keep an inventory. Some sort of barcode system, presumably. So,  
>>>>> you'd
>>>>> need a barcode reader in there as well.
>>>>> All your projects seem pretty cool :) I'm quite impressed. And  
>>>>> if you
>>>>> do make an automated matching facility, make sure to let us  
>>>>> know :D
>>>>>
>>>>> Cheers
>>>>> Damian
>>>>>
>>>>> On 7/18/08, Csaba Zvekan <czvekan at gmail.com> wrote:
>>>>>>
>>>>>> Ohh that's no problem I also thought of that as  
>>>>>> well . :) ...lol...
>>>>>>
>>>>>> see my DIY CNC/ SMD pick and place project :
>>>>>>
>>>>>> http://www.youtube.com/watch?v=hOVnKK6m5a4
>>>>>>
>>>>>> ...lol..
>>>>>>
>>>>>>
>>>>>> Just kidding it just mills and drills ... could be modified   
>>>>>> though :)
>>>>>>
>>>>>> Csaba
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Jul 18, 2008, at 10:00 PM, cheater cheater wrote:
>>>>>>
>>>>>>
>>>>>>> The only thing we need now is to come up with a robotic arm to  
>>>>>>> load
>>>>>>> transistors from SMD mounting tape, then we can run&forget for  
>>>>>>> two
>>>>>>> weeks and have a very nicely matched bulk of transistors. :)
>>>>>>> I assume this is what companies normally use to match them?
>>>>>>>
>>>>>>> Cheers
>>>>>>> Damian
>>>>>>>
>>>>>>> On 7/18/08, Csaba Zvekan <czvekan at gmail.com> wrote:
>>>>>>>
>>>>>>>> Ian ,
>>>>>>>>
>>>>>>>> I am by now means an electronic guru . And can not answer your
>>>>>>>> question.
>>>>>>>> All I know is that I have matched some transistors (BC547)  
>>>>>>>> for a VCO
>>>>>>
>>>>>> project
>>>>>>>>
>>>>>>>> (Yves VCO Yusynths
>>>>>>>> http://yusynth.net/Modular/EN/VCO/index.html
>>>>>>>> and compared with the LM394 SuperMatched Pair) . And find no
>>>>>>>> noticeable
>>>>>>>> difference in temperature drift or anything.
>>>>>>>> The only difference is the price  compare for yourself LM394 is
>>>>>>>> 22.35$
>>>>>>
>>>>>> and
>>>>>>>>
>>>>>>>> two BC547 is 0.20$ . Ok you would still need to purchase a  
>>>>>>>> bunch to
>>>>>>
>>>>>> compared
>>>>>>>>
>>>>>>>> them. But you get the idea.
>>>>>>>> All though I must say that the precision OP-AMP OP490  is  
>>>>>>>> rather
>>>>>>
>>>>>> expensive
>>>>>>>>
>>>>>>>> ( 15.70$ @ farnell.com )  :( but hey , we want precision,  
>>>>>>>> right ? And
>>>>>>
>>>>>> it's
>>>>>>>>
>>>>>>>> not like we need to buy hundred of them. The rest of the  
>>>>>>>> project is
>>>>>>
>>>>>> rather
>>>>>>>>
>>>>>>>> cheap .
>>>>>>>> Make sure you handle measuring in the morning and touch the
>>>>>>>> transistors
>>>>>>>> with tweezers. Also give it some minutes to settle . You 'll  
>>>>>>>> get the
>>>>>>
>>>>>> hang of
>>>>>>>>
>>>>>>>> it.
>>>>>>>> The original design I got from here:
>>>>>>>>
>>>>>>>>
>>>>>> http://electronicdesign.com/Articles/Index.cfm?AD=1&AD=1&ArticleID=6251
>>>>>>>>
>>>>>>>> Csaba
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Jul 18, 2008, at 4:24 PM, Ian Fritz wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> At 05:29 AM 7/18/2008, Csaba Zvekan wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> We SDIY people always need matched transistor pairs :
>>>>>>>>>>
>>>>>>>>>> that's why I recommend this:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>
>>>>>>
>>>>>> http://www.csaba.ch/index.php?option=com_content&task=view&id=14&Itemid=30
>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Is there some advantage of this over a simple bridge  
>>>>>>>>> circuit?  How
>>>>>>>>>
>>>>>>>> precisely can you measure the matching?
>>>>>>>>
>>>>>>>>>
>>>>>>>>> Ian
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
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>>>>>>>>
>>>>>>>
>>>>>>
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