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Tripmaster 3rd February 2009 10:49 AM

Transistor Question
 
Hello

I am currently building the Pedja Rogicís discrete power supply for my dual mono Chipamp LM3886.

I have assembled the V+ section of the power supply and have started positioning the components for the V-. I have just noticed the component supplier has sent three types of BD140 Transistor.

BD140, BD140-16 and BD140-16R4

Is it ok to use a BD140 and a 16 in the same circuit?

It looks like they are also from three different manufactures.

Thanks for your help

Richard

Nuuk 3rd February 2009 12:16 PM

Not sure Richard. Best to ask Cricklewood! ;)

Tripmaster 3rd February 2009 12:31 PM

Quote:

Originally posted by Nuuk
Not sure Richard. Best to ask Cricklewood! ;)

Hi Nick

I was really unimpressed with their attitude when I chased a late delivery. I wanted to be armed with the facts before I call them.

Iíve looked on various spec sheets but cant seam to find any useful information.

Richard :)

Tripmaster 3rd February 2009 12:57 PM

I just called Crinklewood and spoke to Chris who was very helpful :)

Ď-16í refers to a plastic back transistor and ĎR4í is the metal back version.

He also said all of the transistors regardless of make will perform in exactly the same way.

lineup 3rd February 2009 02:38 PM

Yes, they are basically same transistor.
There can be some variation in HFE, gain.

BD140-16 .. is the most usual, lowest gain class ( ~160 )
BD140-25 .. is a class for those exemplars with higher gain ( ~250 )

BD140 .. only, can be in any gain span, is not classified and marked
with any of the above

Personally I have never seen any marked R4. The metalback.

Tripmaster 3rd February 2009 03:54 PM

Quote:

Originally posted by lineup
Yes, they are basically same transistor.
There can be some variation in HFE, gain.

BD140-16 .. is the most usual, lowest gain class ( ~160 )
BD140-25 .. is a class for those exemplars with higher gain ( ~250 )

BD140 .. only, can be in any gain span, is not classified and marked
with any of the above

Personally I have never seen any marked R4. The metalback.

Thanks for the info.

Would you recommend I change them all to the same type?

Richard

mjf 3rd February 2009 04:02 PM

hello all to you.
the number behind the bd 140 - designation is the hfe-classifikation,there are some from 6,10,16,..............the bigger number means the greater hfe-value.
what hfe - (minimum )value you need depends on your circuit design..........
greetings.........

Tripmaster 3rd February 2009 04:37 PM

Quote:

Originally posted by mjf
hello all to you.
the number behind the bd 140 - designation is the hfe-classifikation,there are some from 6,10,16,..............the bigger number means the greater hfe-value.
what hfe - (minimum )value you need depends on your circuit design..........
greetings.........


Hello again

I am building the power supply schematic at the bottom of this page

Discrete Regulated

http://myweb.tiscali.co.uk/nuukspot/...p/supplies.htm

Richard

mjf 3rd February 2009 05:02 PM

hello.
the schematic with the three-transistor-darlington?- i think this will give you enough current amplifikation (high hfe - value......).
but perhaps there will be a little problem with the heat-dissipation with loud music,i did not calculate it but i think yuo will need big heatsinks........
greetings.........

Tripmaster 3rd February 2009 05:20 PM

2 Attachment(s)
Quote:

Originally posted by mjf
hello.
the schematic with the three-transistor-darlington?- i think this will give you enough current amplifikation (high hfe - value......).
but perhaps there will be a little problem with the heat-dissipation with loud music,i did not calculate it but i think yuo will need big heatsinks........
greetings.........


So just to recap, can I use a BD140 and a BD140-16 side-by-side in the V- supply?


I was going to make some heat sinks like the ones in Nuuks picture.


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