Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

In , on 12/05/03
at 03:21 PM, Dave Ryman said:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get
which handles the current required.

All of the IC based voltage regulators (VR) I've found will
either not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be
able to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through until the desired voltage is attained. I would have thought
that there would be a circuit out there (using power transistors or
something) which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Realize that starting with 40V you will need to get rid of a
significant amount of heat -- whatever approach you take ( 10A x 18V =
180 Watts).

While IC's allow quick and easy design, they are not always the most
apropriate way to go. I haven't checked recently, but National
Semiconductor had published a few excellent application notes on how to
design regulated power supplies.

-----------------------------------------------------------
SPAM:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, SPAMers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/05/03
at 03:21 PM, Dave Ryman said:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get
which handles the current required.

All of the IC based voltage regulators (VR) I've found will
either not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be
able to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through until the desired voltage is attained. I would have thought
that there would be a circuit out there (using power transistors or
something) which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Realize that starting with 40V you will need to get rid of a
significant amount of heat -- whatever approach you take ( 10A x 18V =
180 Watts).

While IC's allow quick and easy design, they are not always the most
apropriate way to go. I haven't checked recently, but National
Semiconductor had published a few excellent application notes on how to
design regulated power supplies.

-----------------------------------------------------------
SPAM:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, SPAMers are ruining my mailbox]
-----------------------------------------------------------

In , on 12/05/03
at 03:21 PM, Dave Ryman said:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get
which handles the current required.

All of the IC based voltage regulators (VR) I've found will
either not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be
able to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through until the desired voltage is attained. I would have thought
that there would be a circuit out there (using power transistors or
something) which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Realize that starting with 40V you will need to get rid of a
significant amount of heat -- whatever approach you take ( 10A x 18V =
180 Watts).

While IC's allow quick and easy design, they are not always the most
apropriate way to go. I haven't checked recently, but National
Semiconductor had published a few excellent application notes on how to
design regulated power supplies.

-----------------------------------------------------------
SPAM:
wordgame:123(abc):14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13 (Barry Mann)
[sorry about the puzzle, SPAMers are ruining my mailbox]
-----------------------------------------------------------

Dave Ryman wrote in
.4:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will
either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be
able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something)
which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.


I would look again for a transformer that will handle what you need.

Allied has a fairly good selection at
http://www.alliedelec.com/catalog/pf.asp?FN=619.pdf

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

Dave Ryman wrote in
.4:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will
either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be
able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something)
which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.


I would look again for a transformer that will handle what you need.

Allied has a fairly good selection at
http://www.alliedelec.com/catalog/pf.asp?FN=619.pdf

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

Dave Ryman wrote in
.4:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will
either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be
able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something)
which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.


I would look again for a transformer that will handle what you need.

Allied has a fairly good selection at
http://www.alliedelec.com/catalog/pf.asp?FN=619.pdf

r


--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.

Rich Andrews wrote in
.44:

(snip)

Any ideas or suggestions would be very welcome.


I would look again for a transformer that will handle what you need.

Allied has a fairly good selection at
http://www.alliedelec.com/catalog/pf.asp?FN=619.pdf

r



But I will still need to regulate my output voltage somehow, won't I?
The current being drawn through the regulator will still be a problem.

The only UK supplier that I can find who supplies a decent range of
products is Maplin, and that trasnsformer is the nearest I could find
there.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Rich Andrews wrote in
.44:

(snip)

Any ideas or suggestions would be very welcome.


I would look again for a transformer that will handle what you need.

Allied has a fairly good selection at
http://www.alliedelec.com/catalog/pf.asp?FN=619.pdf

r



But I will still need to regulate my output voltage somehow, won't I?
The current being drawn through the regulator will still be a problem.

The only UK supplier that I can find who supplies a decent range of
products is Maplin, and that trasnsformer is the nearest I could find
there.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Rich Andrews wrote in
.44:

(snip)

Any ideas or suggestions would be very welcome.


I would look again for a transformer that will handle what you need.

Allied has a fairly good selection at
http://www.alliedelec.com/catalog/pf.asp?FN=619.pdf

r



But I will still need to regulate my output voltage somehow, won't I?
The current being drawn through the regulator will still be a problem.

The only UK supplier that I can find who supplies a decent range of
products is Maplin, and that trasnsformer is the nearest I could find
there.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

(Barry Mann) wrote in news:3fd0a8fa$1$avgroveq
:

(snip)
You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Two in series? Do you mean 240-40v followed by 40v-22v?


Realize that starting with 40V you will need to get rid of a
significant amount of heat -- whatever approach you take ( 10A x 18V =
180 Watts).

While IC's allow quick and easy design, they are not always the most
apropriate way to go. I haven't checked recently, but National
Semiconductor had published a few excellent application notes on how to
design regulated power supplies.

(snip)


Thanks for the tip - I'll have a look at the nat semi website.



--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

(Barry Mann) wrote in news:3fd0a8fa$1$avgroveq
:

(snip)
You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Two in series? Do you mean 240-40v followed by 40v-22v?


Realize that starting with 40V you will need to get rid of a
significant amount of heat -- whatever approach you take ( 10A x 18V =
180 Watts).

While IC's allow quick and easy design, they are not always the most
apropriate way to go. I haven't checked recently, but National
Semiconductor had published a few excellent application notes on how to
design regulated power supplies.

(snip)


Thanks for the tip - I'll have a look at the nat semi website.



--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

(Barry Mann) wrote in news:3fd0a8fa$1$avgroveq
:

(snip)
You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Two in series? Do you mean 240-40v followed by 40v-22v?


Realize that starting with 40V you will need to get rid of a
significant amount of heat -- whatever approach you take ( 10A x 18V =
180 Watts).

While IC's allow quick and easy design, they are not always the most
apropriate way to go. I haven't checked recently, but National
Semiconductor had published a few excellent application notes on how to
design regulated power supplies.

(snip)


Thanks for the tip - I'll have a look at the nat semi website.



--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

How about using a couple of 12V transformers/power supplies in series to get 24V
which will be very close to your desired voltage. Then you can use a normal
bipolar transistor to regulate the voltage with a zener diode on the base to
control the voltage to 22 volts. And as you'll only be dropping about 2 volts,
the power dissipation will be minimal and easily dealt with. And 12 volt power
supplies are easy to get in any desired power range - heck most computers use
ones that have a 10 amp rating on the 12 volt line.

Anyway the schematic you need to design a voltage regulator are at:

http://www.tpub.com/neets/book7/27k.htm


On 5 Dec 2003 15:21:59 GMT, Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.


---------------------------------------------------------------
Alan Peterman al at scn.rain.com Tigard, OR
As I grow older, the days seem longer and the years seem shorter.

How about using a couple of 12V transformers/power supplies in series to get 24V
which will be very close to your desired voltage. Then you can use a normal
bipolar transistor to regulate the voltage with a zener diode on the base to
control the voltage to 22 volts. And as you'll only be dropping about 2 volts,
the power dissipation will be minimal and easily dealt with. And 12 volt power
supplies are easy to get in any desired power range - heck most computers use
ones that have a 10 amp rating on the 12 volt line.

Anyway the schematic you need to design a voltage regulator are at:

http://www.tpub.com/neets/book7/27k.htm


On 5 Dec 2003 15:21:59 GMT, Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.


---------------------------------------------------------------
Alan Peterman al at scn.rain.com Tigard, OR
As I grow older, the days seem longer and the years seem shorter.

How about using a couple of 12V transformers/power supplies in series to get 24V
which will be very close to your desired voltage. Then you can use a normal
bipolar transistor to regulate the voltage with a zener diode on the base to
control the voltage to 22 volts. And as you'll only be dropping about 2 volts,
the power dissipation will be minimal and easily dealt with. And 12 volt power
supplies are easy to get in any desired power range - heck most computers use
ones that have a 10 amp rating on the 12 volt line.

Anyway the schematic you need to design a voltage regulator are at:

http://www.tpub.com/neets/book7/27k.htm


On 5 Dec 2003 15:21:59 GMT, Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.


---------------------------------------------------------------
Alan Peterman al at scn.rain.com Tigard, OR
As I grow older, the days seem longer and the years seem shorter.

Dave Ryman wrote:

Thanks for the tip - I'll have a look at the nat semi website.


I think you'd be better off using the national Semiconductor
LM3886TF and an unregulated supply instead of the TDA1514. As
Gary Clifton states in
http://www.dckits.com/app1.htm :

"My own preferences are for the TDA1514 in automotive
applications where power comes from a regulated switching
power supply and the LM3886 for line-powered applications
where a transformer can be used to provide an unregulated supply."

Take a good look at:
http://www.national.com/an/AN/AN-1192.pdf

Dave Ryman wrote:

Thanks for the tip - I'll have a look at the nat semi website.


I think you'd be better off using the national Semiconductor
LM3886TF and an unregulated supply instead of the TDA1514. As
Gary Clifton states in
http://www.dckits.com/app1.htm :

"My own preferences are for the TDA1514 in automotive
applications where power comes from a regulated switching
power supply and the LM3886 for line-powered applications
where a transformer can be used to provide an unregulated supply."

Take a good look at:
http://www.national.com/an/AN/AN-1192.pdf

Dave Ryman wrote:

Thanks for the tip - I'll have a look at the nat semi website.


I think you'd be better off using the national Semiconductor
LM3886TF and an unregulated supply instead of the TDA1514. As
Gary Clifton states in
http://www.dckits.com/app1.htm :

"My own preferences are for the TDA1514 in automotive
applications where power comes from a regulated switching
power supply and the LM3886 for line-powered applications
where a transformer can be used to provide an unregulated supply."

Take a good look at:
http://www.national.com/an/AN/AN-1192.pdf

henryf wrote in news:kb3Ab.428$7p2.216
@newsread2.news.atl.earthlink.net:

Dave Ryman wrote:

Thanks for the tip - I'll have a look at the nat semi website.


I think you'd be better off using the national Semiconductor
LM3886TF and an unregulated supply instead of the TDA1514. As
Gary Clifton states in
http://www.dckits.com/app1.htm :

"My own preferences are for the TDA1514 in automotive
applications where power comes from a regulated switching
power supply and the LM3886 for line-powered applications
where a transformer can be used to provide an unregulated supply."

Take a good look at:
http://www.national.com/an/AN/AN-1192.pdf




Ok, I'll have a look at that. The LM3886 was my first choice, but I had
supply problems (that's before I found the RS website - Doh!).

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

henryf wrote in news:kb3Ab.428$7p2.216
@newsread2.news.atl.earthlink.net:

Dave Ryman wrote:

Thanks for the tip - I'll have a look at the nat semi website.


I think you'd be better off using the national Semiconductor
LM3886TF and an unregulated supply instead of the TDA1514. As
Gary Clifton states in
http://www.dckits.com/app1.htm :

"My own preferences are for the TDA1514 in automotive
applications where power comes from a regulated switching
power supply and the LM3886 for line-powered applications
where a transformer can be used to provide an unregulated supply."

Take a good look at:
http://www.national.com/an/AN/AN-1192.pdf




Ok, I'll have a look at that. The LM3886 was my first choice, but I had
supply problems (that's before I found the RS website - Doh!).

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

henryf wrote in news:kb3Ab.428$7p2.216
@newsread2.news.atl.earthlink.net:

Dave Ryman wrote:

Thanks for the tip - I'll have a look at the nat semi website.


I think you'd be better off using the national Semiconductor
LM3886TF and an unregulated supply instead of the TDA1514. As
Gary Clifton states in
http://www.dckits.com/app1.htm :

"My own preferences are for the TDA1514 in automotive
applications where power comes from a regulated switching
power supply and the LM3886 for line-powered applications
where a transformer can be used to provide an unregulated supply."

Take a good look at:
http://www.national.com/an/AN/AN-1192.pdf




Ok, I'll have a look at that. The LM3886 was my first choice, but I had
supply problems (that's before I found the RS website - Doh!).

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Dave Ryman wrote in message . 1.4...
(Barry Mann) wrote in news:3fd0a8fa$1$avgroveq
:

(snip)
You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Two in series? Do you mean 240-40v followed by 40v-22v?

I presume he means that you could find two transformers with only ONE
secondary output and connect them together:

-----*--- --------------
| )|(
| )|(
--*------ -
| | |
| --- -*------------
| )|(
| )|(
------ --------------

In this case you would need two 1x18V 180VA transformers or something
(you'd have to think a bit if 18V is sufficient to get the 22VDC after
rectification)

Dave Ryman wrote in message . 1.4...
(Barry Mann) wrote in news:3fd0a8fa$1$avgroveq
:

(snip)
You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Two in series? Do you mean 240-40v followed by 40v-22v?

I presume he means that you could find two transformers with only ONE
secondary output and connect them together:

-----*--- --------------
| )|(
| )|(
--*------ -
| | |
| --- -*------------
| )|(
| )|(
------ --------------

In this case you would need two 1x18V 180VA transformers or something
(you'd have to think a bit if 18V is sufficient to get the 22VDC after
rectification)

Dave Ryman wrote in message . 1.4...
(Barry Mann) wrote in news:3fd0a8fa$1$avgroveq
:

(snip)
You should be able to find a more appropriate transformer. If this is a
one time project, two more appropriate transformers in series may work
for you. (It's a bit clunky, but it can work.) Many times you can find
a surplus power supply that will do the job cheaper and better than
your own design.

Two in series? Do you mean 240-40v followed by 40v-22v?

I presume he means that you could find two transformers with only ONE
secondary output and connect them together:

-----*--- --------------
| )|(
| )|(
--*------ -
| | |
| --- -*------------
| )|(
| )|(
------ --------------

In this case you would need two 1x18V 180VA transformers or something
(you'd have to think a bit if 18V is sufficient to get the 22VDC after
rectification)

Mr. Rayman:

You seems to be a knowledgable person.

Transformers can be used only for AC (Alternating Current).

DC (Direct Current) can be dropped easily by adding a load in
Series (e.g.: you hook-up a light bulb between the source current
and the application). You will have to make the calculations
to find the resistance of light buld (or may be an electric heater)
required. Ask a 10th grader (physics) to do the calculations for you

Note: The multi-plug strips, used in hooking many items to one
jack is a Parallel Connection. All hooked up items get
the same voltage



Sudhir


----------------------



Dave Ryman wrote in message . 1.4...
Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

Mr. Rayman:

You seems to be a knowledgable person.

Transformers can be used only for AC (Alternating Current).

DC (Direct Current) can be dropped easily by adding a load in
Series (e.g.: you hook-up a light bulb between the source current
and the application). You will have to make the calculations
to find the resistance of light buld (or may be an electric heater)
required. Ask a 10th grader (physics) to do the calculations for you

Note: The multi-plug strips, used in hooking many items to one
jack is a Parallel Connection. All hooked up items get
the same voltage



Sudhir


----------------------



Dave Ryman wrote in message . 1.4...
Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

Mr. Rayman:

You seems to be a knowledgable person.

Transformers can be used only for AC (Alternating Current).

DC (Direct Current) can be dropped easily by adding a load in
Series (e.g.: you hook-up a light bulb between the source current
and the application). You will have to make the calculations
to find the resistance of light buld (or may be an electric heater)
required. Ask a 10th grader (physics) to do the calculations for you

Note: The multi-plug strips, used in hooking many items to one
jack is a Parallel Connection. All hooked up items get
the same voltage



Sudhir


----------------------



Dave Ryman wrote in message . 1.4...
Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

(Sudhir) wrote in
om:

Mr. Rayman:

You seems to be a knowledgable person.

Transformers can be used only for AC (Alternating Current).

DC (Direct Current) can be dropped easily by adding a load in
Series (e.g.: you hook-up a light bulb between the source current
and the application). You will have to make the calculations
to find the resistance of light buld (or may be an electric heater)
required. Ask a 10th grader (physics) to do the calculations for you

Note: The multi-plug strips, used in hooking many items to one
jack is a Parallel Connection. All hooked up items get
the same voltage



Sudhir


----------------------



Dave Ryman wrote in message
. 1.4...
Hi,
I need to drop 40vdc down to 22vdc, my application requires
the
latter, and the former is the lowest voltage transformer I can get
which handles the current required.

All of the IC based voltage regulators (VR) I've found will
either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must
be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through
until the desired voltage is attained. I would have thought that
there would be a circuit out there (using power transistors or
something) which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.


Hmmm. Well, first - I do know that transformers can only be used for AC.
I was taking this to be common knowledge, and so didn't ramble on about
rctifiers and things - it would have just muddied things.

second - the point is not just to shed a couple of volts, but to provide
a stablised voltage.

You seems to be a knowledgable person, too.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

(Sudhir) wrote in
om:

Mr. Rayman:

You seems to be a knowledgable person.

Transformers can be used only for AC (Alternating Current).

DC (Direct Current) can be dropped easily by adding a load in
Series (e.g.: you hook-up a light bulb between the source current
and the application). You will have to make the calculations
to find the resistance of light buld (or may be an electric heater)
required. Ask a 10th grader (physics) to do the calculations for you

Note: The multi-plug strips, used in hooking many items to one
jack is a Parallel Connection. All hooked up items get
the same voltage



Sudhir


----------------------



Dave Ryman wrote in message
. 1.4...
Hi,
I need to drop 40vdc down to 22vdc, my application requires
the
latter, and the former is the lowest voltage transformer I can get
which handles the current required.

All of the IC based voltage regulators (VR) I've found will
either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must
be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through
until the desired voltage is attained. I would have thought that
there would be a circuit out there (using power transistors or
something) which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.


Hmmm. Well, first - I do know that transformers can only be used for AC.
I was taking this to be common knowledge, and so didn't ramble on about
rctifiers and things - it would have just muddied things.

second - the point is not just to shed a couple of volts, but to provide
a stablised voltage.

You seems to be a knowledgable person, too.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

(Sudhir) wrote in
om:

Mr. Rayman:

You seems to be a knowledgable person.

Transformers can be used only for AC (Alternating Current).

DC (Direct Current) can be dropped easily by adding a load in
Series (e.g.: you hook-up a light bulb between the source current
and the application). You will have to make the calculations
to find the resistance of light buld (or may be an electric heater)
required. Ask a 10th grader (physics) to do the calculations for you

Note: The multi-plug strips, used in hooking many items to one
jack is a Parallel Connection. All hooked up items get
the same voltage



Sudhir


----------------------



Dave Ryman wrote in message
. 1.4...
Hi,
I need to drop 40vdc down to 22vdc, my application requires
the
latter, and the former is the lowest voltage transformer I can get
which handles the current required.

All of the IC based voltage regulators (VR) I've found will
either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must
be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage
through
until the desired voltage is attained. I would have thought that
there would be a circuit out there (using power transistors or
something) which would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.


Hmmm. Well, first - I do know that transformers can only be used for AC.
I was taking this to be common knowledge, and so didn't ramble on about
rctifiers and things - it would have just muddied things.

second - the point is not just to shed a couple of volts, but to provide
a stablised voltage.

You seems to be a knowledgable person, too.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

Bob



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

Bob



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

Bob



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

In article , remove wrote:


Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

That would take care of the 200 watts dissapation in heat generated from the drop from 40 volts to
22.

greg

In article , remove wrote:


Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

That would take care of the 200 watts dissapation in heat generated from the drop from 40 volts to
22.

greg

In article , remove wrote:


Dave Ryman wrote:

Hi,
I need to drop 40vdc down to 22vdc, my application requires the
latter, and the former is the lowest voltage transformer I can get which
handles the current required.

All of the IC based voltage regulators (VR) I've found will either
not take 40v, or cannot cope with the current required.

Minimum current handling is 8A (preferably 10), the VR must be able
to provide +22v & 0v or -22v & 0v.

I know that the basis of a VR is that it lets more voltage through
until the desired voltage is attained. I would have thought that there
would be a circuit out there (using power transistors or something) which
would allow me to fulfil my needs.

Any ideas or suggestions would be very welcome.

--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

That would take care of the 200 watts dissapation in heat generated from the drop from 40 volts to
22.

greg

(gregs) wrote in
:

In article , remove
wrote:


(snip)
--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

That would take care of the 200 watts dissapation in heat generated
from the drop from 40 volts to 22.

greg


I have revised my design to use a 25v transformer instead of 40v. I
couldn't find one on Maplin, have switched to RS components - who do a
better range.

Anyway, my voltage drop isn't going to be nearly as large now.

Thanks for the feedback.

I am currently looking at a design which passes the additional current
required via some power transformers, with the VR just handling 1A. I
found this design on the web -
http://www.pclincs.co.uk/Forums/showthread/t-293.html - I'm not sure yet
how to adapt it to my needs for voltage and current. I've already worked
out a VR IC to give me 22v, but how this affects the other components,
I'm not too sure yet.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

(gregs) wrote in
:

In article , remove
wrote:


(snip)
--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

That would take care of the 200 watts dissapation in heat generated
from the drop from 40 volts to 22.

greg


I have revised my design to use a 25v transformer instead of 40v. I
couldn't find one on Maplin, have switched to RS components - who do a
better range.

Anyway, my voltage drop isn't going to be nearly as large now.

Thanks for the feedback.

I am currently looking at a design which passes the additional current
required via some power transformers, with the VR just handling 1A. I
found this design on the web -
http://www.pclincs.co.uk/Forums/showthread/t-293.html - I'm not sure yet
how to adapt it to my needs for voltage and current. I've already worked
out a VR IC to give me 22v, but how this affects the other components,
I'm not too sure yet.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

(gregs) wrote in
:

In article , remove
wrote:


(snip)
--
Thanks,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one

Simple, use a brick DC/DC switching multi voltage regulator.
Many OEM suppliers sell them. 48 volt would be the closest
std dc input voltage.

That would take care of the 200 watts dissapation in heat generated
from the drop from 40 volts to 22.

greg


I have revised my design to use a 25v transformer instead of 40v. I
couldn't find one on Maplin, have switched to RS components - who do a
better range.

Anyway, my voltage drop isn't going to be nearly as large now.

Thanks for the feedback.

I am currently looking at a design which passes the additional current
required via some power transformers, with the VR just handling 1A. I
found this design on the web -
http://www.pclincs.co.uk/Forums/showthread/t-293.html - I'm not sure yet
how to adapt it to my needs for voltage and current. I've already worked
out a VR IC to give me 22v, but how this affects the other components,
I'm not too sure yet.

--
Regards,
Dave


http://welcome.to/daves.website
http://travel.to/formula.one