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Old 13th January 2014, 02:49 PM   #1
tvrgeek is offline tvrgeek  United States
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Default Current thoughts on transistor matching

Done this a lot, but I always wind up with a kluge on a perf board. I am about to build a new amp and need to match both low power BJT as well as high power outputs. Not looking for a full blown old Tek curve tracer. Are there any "simple" boxes out there to match for Beta at various loads better that 1%?
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Old 13th January 2014, 06:08 PM   #2
skidave is offline skidave  United States
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Have you looked at this device:
AnaTek Corporation - Peak Atlas DCA75

I don't have one yet, but it looks valuable. This is a slightly newer versions with USB connectivity Vs the original model.

Dave
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Old 13th January 2014, 09:05 PM   #3
tvrgeek is offline tvrgeek  United States
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That looks really cool for low power devices. Curve tracer too! I had not seen it. It will take some reading and maybe that will lead to others.

For output matching, I would think I would want to match at the minimum, at quiescent, so I need 130mA or more. Even the last set of inputs I did came out different at half a mA than 2mA.
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Old 13th January 2014, 09:10 PM   #4
tvrgeek is offline tvrgeek  United States
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Accuracy not that good. Can't tell if their specs are absolute, or if their relative accuracy is actually much better. Kind of fixed at 5 mA Ic. Would sure tell you good or bad though.
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Old 14th January 2014, 05:21 PM   #5
Mr Evil is offline Mr Evil  United Kingdom
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You could try "locky_z's intelligent curve tracer", which is capable of up to 2.5A, so it can cope with power transistors. They come up for sale on eBay every so often. I have one myself, and it works very well.
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Old 14th January 2014, 08:48 PM   #6
RNMarsh is offline RNMarsh  United States
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here is another choice for you: DUOYI model DY294 transistor tester. Also available from MIB Instruments --> www.mib-instrumenets.com

-RM
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Old 14th January 2014, 09:18 PM   #7
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Quote:
Originally Posted by skidave View Post
Have you looked at this device:
AnaTek Corporation - Peak Atlas DCA75

I don't have one yet, but it looks valuable. This is a slightly newer versions with USB connectivity Vs the original model.

Dave
I have one and was impressed with it.
It doesn't even care how you connect it up.

I was having trouble with an amp oscillating and it showed the HFE of my new transistors was far too high.
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Old 17th January 2014, 11:17 PM   #8
tvrgeek is offline tvrgeek  United States
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Quote:
Originally Posted by nigelwright7557 View Post
I have one and was impressed with it.
It doesn't even care how you connect it up.

I was having trouble with an amp oscillating and it showed the HFE of my new transistors was far too high.
HIGH? Doesn't that give you some opportunity to tweak some things? My problem on my Hafler rebuild some time ago was some OnSemi that came in at half the minimum or worse.

Kind of looks like I should stick with my breadboard or find an old Heath. If I needed yet another DVM, I might grab one with an hfe range. 5 is enough for now. A curve tracer is way out of the budget.
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Old 21st January 2014, 08:21 PM   #9
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Build Rod Elliot's Transistor matching circuit. Works a beaut!!
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