40411 transistor equivalent?

[neazoi]

Hello, I would like to build this PSU https://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/2V-36V_10A_PS_WB6TOX.gif because I like discrete.

I am looking for a transistor equivalent for the 40411



If you can suggest similar circuits with newer transistors please let me know as well.

 

[lordgty]

Use any npn transistor with equivalent current ratings

 

[neazoi]

Use any npn transistor with equivalent current ratings

I knew that
Which one?

 

[FvM]

I don't assume that the author of this sloppily designed circuit spent much time on calculating transistor specifications. Everything you calculate yourself won't be worse than the original.

 

[neazoi]

I don't assume that the author of this sloppily designed circuit spent much time on calculating transistor specifications. Everything you calculate yourself won't be worse than the original.

Have you got any other discrete PSU to propose? greater than 2A.
I would like to use one with the bd436 or similar but I cannot find one.

 

[FvM]

The basic circuit isn't bad at all, if you can live with lack of overcurrent protection. Unfortunately, there's a certain risk that a breakdown of power transistors is triggered by an output short before the fuse blows.

What I meant with sloppy design are things like missing BE resistors and insufficient transformer rating, must be 16 A for 10 A continuous output current. The transistor heatsink requirements aren't mentioned at all.

If the DC input voltage is guaranteed not to exceed 60V, three 2N3055 can replace two 40411 for the present circuit, or recent "plastic" transistors like BD249.

P.S.: As the circuit has already emitter resistors with about 1.1 V voltage drop at rated current, it's quite easy to supplement a simple current limiting circuit. To allow lower current limits than about 6A, a current sense amplifier would be needed, for 6 to 10A, a one transistor circuit does the trick.