LM7812 need to boost current.

[thanong]

greeting everyone,I have positive regulator I.C LM 7812 need to boost output current around 2 ampere.How to add transistor to get that current.I don't want to use 317 series,can anyone please give me simple circuit to wirring will very appreciate ( I use this I.C regulator to heat 12AX7 filament it work fine and sound good enough for my ears but I need more current).Thanks foward.

[Juergen Knoop]

so what about 78S12?

[thanong]

Originally Posted by Juergen Knoop

so what about 78S12?

Thanks Juergen,I din't try yet now I'm home a lot of snow around Seattle,Washington USA.I can't go anywhere soon,but I have NPN transistor in hand I just want to try to add transistor to boost current first.

[Puffin]

This works well. I have built it.



I have used BD139 for Q1.

Full information here

http://www.extremecircuits.net/2009/...r-circuit.html

http://www.extremecircuits.net/p/com...-projects.html

[thanong]

Originally Posted by Puffin

This works well. I have built it.



I have used BD139 for Q1.

Hi Puffin,awesome my man this what I really need.Can you give me the value of R1,R2 please.Many thanks.

[thanong]

Originally Posted by thanong

Hi Puffin,awesome my man this what I really need.Can you give me the value of R1,R2 please.Many thanks.

Thank you very much Puffin I got it.It work now.Very appreciate and you have a good evening guy.

[Puffin]

If you need 2A you could use an extra transistor like this :-

[Enzo]

Look up some 7812 data sheets. I can;t say for all of them, but some will have basic sample circuits, one of which will be that current boost.

Meanwhile, a 12AX7 at 12v needs 150ma. How many 12AX7s do you have to need 2A for them?

[6L6]

thanong -

Can you give us a bit more information? Specifically,

What is this being used in?
What is your voltage supply? (What transformer, rectification, etc...)
What is the load? You mention filaments, what kind of tubes? How many?
You say you want to 'boost the current' Can you elaborate?