Replacements for BC307B and BC237B ?

[turboyam]

I have a hard time finding quality replacements for those?.
They are TO-92's and have to be matched. I need those for a SAE 2600 main board and protection circuit.
What would you guys suggest?
Thanks! 🙂

 

[tomchr]

I bet BC547B and BC557B would work just fine. BC546B and BC556B would work as well. All four are available at Digikey.

Tom

 

[turboyam]

Thanks for the info 🙂 but none in stock right now 🙁 . Any other ideas?

 

[JMFahey]

Try Mouser or about anybody else, they are as common as can be.

 

[JonSnell Electronic]

How many originals do you want?
Bipolar Transistors | RS Components
http://uk.rs-online.com/web/c/semic...448267573743D6263323337267374613D626332333726

 

[turboyam]

John, you have the original BC237B and BC307B 'S ?. I did find some 547 & 557 and 546& 556 at Mouser. I had checked at Digikey, my favorite place...
I would want 20 each? 237 and 307, to match them.

 

[turboyam]

Found some original ones, from Onsemi at Rochester but slightly over priced... I know i'm not into boat loads quantity but @ $8. 50 EACH!!!!!!!!!!! Hhahaahhahaha!.

 

[tomchr]

You can strip off the B and see what you can turn up. The A, B, and C grades refer to the hfe of the transistor. A is the lowest (100 I believe), B is the middle grade (250), and C is high hfe (400). The numbers are free from memory, so probably inaccurate, but you can check the data sheet to make sure.

There's usually no harm in using a BC546C instead of a BC546B. Also, if they're used in the protection circuit, you can probably use any NPN/PNP of similar specs that fit the pinout. Even something like BC327/BC337 would probably work.

Tom

 

[Ian Finch]

You have a cheap offer form Rs components of exactly the original types you want. As you want some matched though, you are going to need more - perhaps a lot more than the replacement quantities to sort matches from.

It seems like a search for the same as what you already have in good working condition though. A wipe with a cloth will have them shiny again and there is no point fussing with the replacement of general purpose parts that aren't damaged or deteriorated. They aren't self-destructing like electrolytic caps, so why the need to replace?

 

[tomchr]

Do you have a curve tracer or are you planning to match by Hfe only?

Tom

 

[turboyam]

I do not have a curve tracer. HFE will have to do.

 

[AndrewT]

you could try hFE at two decades of current apart.
100uA, 1mA, 10mA and measure Vbe at those same currents.

 

[turboyam]

You have a cheap offer form Rs components of exactly the original types you want. As you want some matched though, you are going to need more - perhaps a lot more than the replacement quantities to sort matches from.

It seems like a search for the same as what you already have in good working condition though. A wipe with a cloth will have them shiny again and there is no point fussing with the replacement of general purpose parts that aren't damaged or deteriorated. They aren't self-destructing like electrolytic caps, so why the need to replace?

Well RS don't have them is stock, i would have bought from them if they had...