Paradise Builders

[Joachim Gerhard]

The Leds are 2mA low current types from any decent maker. I usually use Knightbridge.

[Joachim Gerhard]

well, the transistors from Fairchild seem not to be well matched. That is the reason i recommended a smaller manufacturer like Diotec. Frans and i got some of this maker and they matched well.

[Bksabath]

Originally Posted by Benedetto

Hi there,
recently ive made my day on studying some specsheets.
About 13 each 327/337 40
Almost every one told me that hfe should be between
250 and 625 with a statistic center @ 400.
So in terms of datasheets the Gauss Bellcurve has to appear
somewhere.
After measuring 1.600 of those creeps im going bonkers....
Aint got enough pairs for just one pair of boards.
Btw its not the fault of those honorable inventors of
Paradise !
Funny,
according to those sheets, Motorola seems not to offer
BC327-40 !
But, anyways, ill go further in it !
Just ordered 500/each more...

Unless one get different wafers about (20K transistors) Hfe will be around the same

So one need try different supliers and different brands
Any one tried ON semy ?

Any Idea how much for big order from manufacturer asking with close Hfe matching.

[LouderIsBetter]

Originally Posted by Bksabath

SO I would really like to have same of yours Hfe 350 to 400 PNP and Swap for my PNP that measure above 540 as my batch is opposite of yours.
Could you help please?

Sounds like a plan. You have a PM.

[Joachim Gerhard]

That is the way it works. Trade them in.

[PierreQuiRoule]

Originally Posted by Bksabath

So one need try different supliers and different brands
Any one tried ON semy ?

I purchased Fairchild npn and pnp devices from Mouser, as well as ON Semi npn and pnp devices from Digikey. The Fairchild npns and pnps don't match together, nor do the On Semi npns and pnps.

But ... it turns out that there are some good matches between the Fairchild pnps and the ON Semi npns, as well as between the Fairchild npns and the ON Semi pnps. So trying different sources, date codes, or manufacturers seems to pay off. I already posted measurements of about 750 devices, and will post in coming weeks measurements of another 750.

The distribution of HFE values I've measured (within the Fairchild population and the ON Semi population) looks like a bimodal. It does not appear to be normal/standard.

Matching and trading is part of the DIY experience IMO.

Pierre

[chip12]

hello
Diotec is OK.
I bought a 100 + 100pcs BC327/337/40. Differences in hfe are minimal. From 380 to 410. Transistors I bought on the tape from SOS electronic

[deadhead]

Originally Posted by chip12

hello
Diotec is OK.
I bought a 100 + 100pcs BC327/337/40. Differences in hfe are minimal. From 380 to 410. Transistors I bought on the tape from SOS electronic

Where can we buy Diotec from?

[studiostevus]

Looks like i was pretty lucky with matching, but i am still a bit confused on what to match to what as i don't get to perfect matching of 8 pnp's to 8 npn's.

Let's first look at the input stage. Say, we have the pcb's, board A and B. each pcb has one pnp bank (4 transistors) and one npn bank (4 transistors). Let's call those bank 1 and 2. So we have 4 banks: A1,A2,B1,B2.

In what priority will we be matching?
- first within each bank?
- secondly between bank 1 and 2 of each pcb?
- thirdly between bank A1 and B1, and between A2 and B2?

Alternatively????
- first between bank 1 and 2 of a single pcb? (this could mean for example bank 1 (npn) could look like 450/475/450/475 and bank 2 (pnp) like 450/475/450/475
- second between pcb's?
- third within a single bank?

Essentially the question is : what are the effects of mismatches, and what is worse
- mismatches within one bank (pnp bank or npn bank)?
- mismatches between the pnp bank and the npn bank?
- mismatches between channels?


Talking servos and regulators, i imagine we are only looking at matches between single pairs of npn and pnp, as these need to be adjusted using trimpots.

Where else is matching crucial?

[deadhead]

Originally Posted by LouderIsBetter

I’m blown away by the accusations here.
.

Mine are not accusations, they are questions.

I only want to build this once and I want it to be right..the best I can make it.

So I triple check the points that I am not sure about and the matching ( or complete absence of matching ) of the transistors is a critical point in my build and my build is stopped at this point.

I would like the designers to write down in simple terms what values I should aim for and what should match what.

None of this is a complaint or implies any criticism .

I am very grateful for what everyone involved has done so far.