Help me find an equivalent power transistor?

[Harry Klippton]

Sorry for the stupid question. I would like to stay with the same TO126 package. The power supply is about 15vDC and the regulator should be putting out about 12vDC. would this be a suitable replacement? I'm a little unsure which specs are most relevant here

 

[rossbalch]

What is the context for this? What is the circuit? Both things you're referencing here are transistors, not voltage regulators as I understand the term. Something like an LM78x for instance.

 

[Harry Klippton]

Perhaps power transistor is the right term rather than voltage regulator. It's in the power supply section of a tascam porta 03 mkii

 

[temol]

Check BD436 or BD438

 

[owlexifry]

this one that you linked appears to put out 1.5W

https://www.mouser.com/ProductDetail/Toshiba/TTA008BQ?qs=B6kkDfuK7%2FAb0K%252Be3vU9lw%3D%3D

the 2SB891 referenced above appears to handle up to 5W.
you'd probably wanna sub with something that will match or exceed that power dissipation rating.

 

[Harry Klippton]

@jwin615 any chance you have 40 of these in a bag or something?

 

[jwin615]

@jwin615 any chance you have 40 of these in a bag or something?

I may have thrown 40 of them out

 

[jwin615]

NTE185
I'll dig around tonight, maybe

 

[jwin615]

Got these reclaims
Not sure if the 185 PN is relevant

Probably of no help.
I probably had the NTE PN a while back, but I trashed everything not immediately useful/valuable in my failing quest to not hoard everything.

 

[Harry Klippton]

Got these reclaims
Not sure if the 185 PN is relevant
View attachment 97595
Probably of no help.
I probably had the NTE PN a while back, but I trashed everything not immediately useful/valuable in my failing quest to not hoard everything.

At the very least that's the wrong package type

 

[Harry Klippton]

I think I'm gonna bite the bullet and buy some extremely overpriced 2sb891s on ebay

 

[jwin615]

2SB891(F) 40V, 2A, 5W, 100MHz
=
2SA1359, 2SB1142...1143

 

[jwin615]

Transistor equivalents

drive.google.com

 

[Harry Klippton]

2SB891(F) 40V, 2A, 5W, 100MHz
=
2SA1359, 2SB1142...1143

2sa1359 looks good and way more available

 

[jwin615]

2sa1359 looks good and way more available

Data sheets look comparable with the 2SA having a couple of larger max ratings but slightly lower potential hFE¹. But I doubt that to be an issue in your use case.
May be worth trying a couple and see if you can get away with not rebiasing. Unless there's trimmers, then, who cares

 

[Harry Klippton]

Data sheets look comparable with the 2SA having a couple of larger max ratings but slightly lower potential hFE¹. But I doubt that to be an issue in your use case.
May be worth trying a couple and see if you can get away with not rebiasing. Unless there's trimmers, then, who cares

I tested a working 2sb891 in another machine and its hfe was in the 200s. I still don't really understand how this transistor works either I'm guessing someone fried it with over voltage? The first filter cap it's connected to was bulged too