psu pass transistor sub

[p.larner]

I am building a linear psu,normaly it uses 2X TIP 3055 items can i sub t4hem using 2X BUW-49 TRANSISTORS INSTEAD,WOULD THEY BE MORE ROBUST?,its a linear psu.

[wraper]

BUW49 is marketed for switching applications only and its specs are all around that. Also weirdly none of its datasheets have current gain spec. No, I suggest refraining from using it for any linear applications.

[BrokenYugo]

ALL CAPS IS EQUIVALENT TO YELLING, PEOPLE DON'T LIKE BEING YELLED AT, LESS YELLING WILL TEND TO RESULT IN MORE HELP.

The pass transistor(s) in a linear supply are supposed to have a DC safe operating area on the safe operating area graph, that's the thing you're looking for in the datasheet. Most power transistors designed/marketed for switching aren't specified for linear/DC use though some older ones are. Be careful with that, stuff can be redesigned, a 20 year old datasheet from brand A does not guarantee performance of a new part from brand B.

[David Hess]

The current gain is suppose to be about 40 at 5 amps.  The real unknown is the safe operating area, but the power rating is 150 watts instead of 115 watts, so I suspect it will be fine.  The higher frequency is more likely to cause local oscillation, so maybe include base stopping resistors or ferrite beads.

[p.larner]

thanks for the answers,my kb was playing up,didnt mean to be rude ie caps lock.