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

[cheater cheater]

Hmm, I assume just testing each transistor on its own and recording
parameters wouldn't be good enough. You really need a circuit of two
transistors, don't you?

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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