Paul Burridge wrote:
On Mon, 20 Oct 2003 11:20:20 -0400, rob34 wrote:


If you want to keep it to a couple transistors they would be expensive.
You are better off using either more NTE-180 or more mj2955, but I would
cut the voltage down to around 18 volts instead of 24 volts as this
higher voltage leads to more heat for the transistors. Rob


How come no one's yet recommeded that great old PSU war-horse, the
2N3055? Six of them on a decent heat sink and you're sorted!

2N3055 are great, but 2N3771 are better! Rob

On Mon, 20 Oct 2003 19:33:02 +0100, Paul Burridge
wrote:

On Mon, 20 Oct 2003 11:20:20 -0400, rob34 wrote:

If you want to keep it to a couple transistors they would be expensive.
You are better off using either more NTE-180 or more mj2955, but I would
cut the voltage down to around 18 volts instead of 24 volts as this
higher voltage leads to more heat for the transistors. Rob

How come no one's yet recommeded that great old PSU war-horse, the
2N3055? Six of them on a decent heat sink and you're sorted!

The main reason I wouldn't use a 2N3055 in that application is the
gain falls of dramatically at high Ic. Design needs to accommodate
this in terms of both driver current capability and loop gain.

On Mon, 20 Oct 2003 19:33:02 +0100, Paul Burridge
wrote:

On Mon, 20 Oct 2003 11:20:20 -0400, rob34 wrote:

If you want to keep it to a couple transistors they would be expensive.
You are better off using either more NTE-180 or more mj2955, but I would
cut the voltage down to around 18 volts instead of 24 volts as this
higher voltage leads to more heat for the transistors. Rob

How come no one's yet recommeded that great old PSU war-horse, the
2N3055? Six of them on a decent heat sink and you're sorted!

The main reason I wouldn't use a 2N3055 in that application is the
gain falls of dramatically at high Ic. Design needs to accommodate
this in terms of both driver current capability and loop gain.

On Mon, 20 Oct 2003 11:20:20 -0400, rob34 wrote:

If you want to keep it to a couple transistors they would be expensive.
You are better off using either more NTE-180 or more mj2955, but I would
cut the voltage down to around 18 volts instead of 24 volts as this
higher voltage leads to more heat for the transistors. Rob

How come no one's yet recommeded that great old PSU war-horse, the
2N3055? Six of them on a decent heat sink and you're sorted!

--

"Windows [n.], A thirty-two bit extension and GUI shell to a sixteen bit patch
to an eight bit operating system originally coded for a four bit
microprocessor and produced by a two bit company."

clarke wrote:
Hi, check this link and see what you need to do,
one or two pass trans. will not do the job for you,
easier to use 6-10 pass trans to share the load.

http://www.mitedu.freeserve.co.uk/Ci...er/1230psu.htm

Is your transformer able to supply necessary power to this supply ?

regards,
clarke


Deos wrote:


Hi everyone I have made a power supply for my rigs

The schematic is the typical regulator with power transistor wrapped around
it for the extra juice.

I need 40 amps continues ..

I tried 4 mj2955 which are rather nice for foot warming in the winter .

I also tried nte-180 which are very good. is there anything better at a
logical price

I would like to keep the number of transistors down to 1 or 2.

Can someone advise my on what to use for power?

--
http://www.qsl.net/sv1hao


If you want to keep it to a couple transistors they would be expensive.
You are better off using either more NTE-180 or more mj2955, but I would
cut the voltage down to around 18 volts instead of 24 volts as this
higher voltage leads to more heat for the transistors. Rob

the trasformer is in the KW range.....
it's a big nasty beast.


--
http://www.qsl.net/sv1hao
"clarke" wrote in message
...
Hi, check this link and see what you need to do,
one or two pass trans. will not do the job for you,
easier to use 6-10 pass trans to share the load.

http://www.mitedu.freeserve.co.uk/Ci...er/1230psu.htm

Is your transformer able to supply necessary power to this supply ?

regards,
clarke


Deos wrote:

Hi everyone I have made a power supply for my rigs

The schematic is the typical regulator with power transistor wrapped
around
it for the extra juice.

I need 40 amps continues ..

I tried 4 mj2955 which are rather nice for foot warming in the winter .

I also tried nte-180 which are very good. is there anything better at a
logical price

I would like to keep the number of transistors down to 1 or 2.

Can someone advise my on what to use for power?

--
http://www.qsl.net/sv1hao

the trasformer is in the KW range.....
it's a big nasty beast.


--
http://www.qsl.net/sv1hao
"clarke" wrote in message
...
Hi, check this link and see what you need to do,
one or two pass trans. will not do the job for you,
easier to use 6-10 pass trans to share the load.

http://www.mitedu.freeserve.co.uk/Ci...er/1230psu.htm

Is your transformer able to supply necessary power to this supply ?

regards,
clarke


Deos wrote:

Hi everyone I have made a power supply for my rigs

The schematic is the typical regulator with power transistor wrapped
around
it for the extra juice.

I need 40 amps continues ..

I tried 4 mj2955 which are rather nice for foot warming in the winter .

I also tried nte-180 which are very good. is there anything better at a
logical price

I would like to keep the number of transistors down to 1 or 2.

Can someone advise my on what to use for power?

--
http://www.qsl.net/sv1hao

"Deos" wrote in message
...
Hi everyone I have made a power supply for my rigs

The schematic is the typical regulator with power transistor wrapped
around
it for the extra juice.

I need 40 amps continues ..
I tried 4 mj2955 which are rather nice for foot warming in the winter .

The function of the pass transistor is to dissipate as heat the difference
between input and output. Sounds like you need a bigger heat sink...or
build a switching supply.
Ray

Hi everyone I have made a power supply for my rigs

The schematic is the typical regulator with power transistor wrapped
around
it for the extra juice.

I need 40 amps continues ..



I tried 4 mj2955 which are rather nice for foot warming in the winter .

I also tried nte-180 which are very good. is there anything better at a
logical price

I would like to keep the number of transistors down to 1 or 2.

Can someone advise my on what to use for power?
========
Assuming that so far you have only considered bi-polar transistors ,perhaps
it would be beneficial to look into the application of Power MOSFETs. In the
'on' state they have a very low resistance ,hence at high currents they
dissipate less heat .
Consequently you would need smaller heat sinks.

Frank GM0CSZ / KN6WH

dont have any idea how to work with mosfet
any links in the right direction?


--
http://www.qsl.net/sv1hao
"Frank Dinger" wrote in message
...
Hi everyone I have made a power supply for my rigs

The schematic is the typical regulator with power transistor wrapped
around
it for the extra juice.

I need 40 amps continues ..



I tried 4 mj2955 which are rather nice for foot warming in the winter .

I also tried nte-180 which are very good. is there anything better at a
logical price

I would like to keep the number of transistors down to 1 or 2.

Can someone advise my on what to use for power?
========
Assuming that so far you have only considered bi-polar transistors
,perhaps
it would be beneficial to look into the application of Power MOSFETs. In
the
'on' state they have a very low resistance ,hence at high currents they
dissipate less heat .
Consequently you would need smaller heat sinks.

Frank GM0CSZ / KN6WH