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

[Csaba Zvekan]

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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