AC Adapters

[Goedjn]

On Tue, 31 Oct 2006 21:40:07 -0500, mm <NOPSAMmm2005@bigfoot.com>
wrote:

On 31 Oct 2006 15:54:35 -0800, "hallerb@aol.com" <hallerb@aol.com
wrote:

I have done a lot of this, changed plugs oon them too.

What the government should do is mandate a standard, 12 volts AC with
standard plug

have the device convert it to DC if necessary, change the voltage
whatever.

since AC has no polarity and a standard plugwe would cut down n the
amount of trash, and simplify things.

What gets me are all the small transformers running all the time using
a little bit of current each. Even when the transformer is inside the
radio, etc, and the on/off swtich could turn off the whole thing, it
never does. Only the secondary.

They should have everything run on 12 volts or whatever, and have one
12 volt transformer at the fuse box that runs everything, with outlets
in every room for 12 volts AC and whatever DC. Heck, they should use
the doorbell transformer for all of this.

Power-over-ethernet, 24V, 12Watts. (thus 1/2 amp?)

 

[Chris Lewis]

According to mm <NOPSAMmm2005@bigfoot.com>:

BTW, my new Motorola "Go Phone" phone came with a wall wart that has
two rings on the plug, plus the center hole. I was going to measure
the voltage soon, but since w'ere on the topic, can anyone tell me
anything about it. The label just says the output is 5.0V with the DC
symbol.

Why do they need two rings, and is the car charger whose plug fits the
jack, that I bought for 50cents at the Carroll County Hamfest, likely
to work or to ruin the phone?

The center pin or one of the rings may not be used at all, or, the
two rings may be connected together. Does the wallwart have a schematic
picture of the connector? They often do.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

 

[Mark Lloyd]

On Tue, 31 Oct 2006 14:53:35 -0800, "Bob F" <bobnospam@gmail.com>
wrote:

"Stormin Mormon" <cayoung61-&spamblock*-@hotmail.com> wrote in message
news:sqP1h.463$zB4.237@twister.nyroc.rr.com...
Well, if you want to diddle up and down, we can henpeck and quibble
over the choice of words. But, mostly, I'd think that the odds of
reusing a wall wart rate between "no effing way" and "who do you think
you're kidding!".


I buy wall warts all the time for gadgets I get at thrift shops
or garage sales. It is not that difficult to find a wart with the
correct voltage and connector/polarity and sufficient current
capacity. Most thrift shops have boxes of them. No problem
re-using them at all.

Bob

Also, you can buy switchable voltage DC wall-warts with
interchangeable plugs that let you use either polarity.
--
54 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[Mark Lloyd]

On Tue, 31 Oct 2006 21:41:44 GMT, "Stormin Mormon"
<cayoung61-&spamblock*-@hotmail.com> wrote:

Well, if you want to diddle up and down, we can henpeck and quibble
over the choice of words. But, mostly, I'd think that the odds of
reusing a wall wart rate between "no effing way" and "who do you think
you're kidding!".

I often look through old power wall-warts when I need one, succeeding
about 75% of the time (if the voltage is common, 6V 9V or 12V).

Exceptions are based on purchasing the same brand and type of
equipment. Many Nokia or Motorola cell phones use the same charger. As
also with some answering machines.

At the moment, I've got wall warts for

- Battery Manager Ultra, battery charger
- battery charger for AA and AAA only
- Answering machine
- Motorola cell phone
- Nokia cell phone
- Last cell phone, can't remember what it was.
- NEC cell phone, still have the old analog phone.
- Panasonic 9.6 volt drills (don't any of them hold a good charge, and
you can't get that model at Home Depot any more).
- Tape recorder

And several other chargers. Like old keys, they don't fit anything any
more, but too good to throw out.

And if you do, THAT will be the one you need.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
.

"Chris Lewis" <clewis@nortelnetworks.com> wrote in message
news:12kfet5effd9hc4@corp.supernews.com...
According to Stormin Mormon <cayoung61-&spamblock*-@hotmail.com>:
In the modern generation, charge plugs known as "wall warts" are
like
coat hangers of the last generation. I've taken to labelling mine
with
a sticker and some writing.

The odds of finding similar voltage and plug design is very slight.
If
the new device is the same voltage, you can use a charge plug with a
higher available amperage, in most situaitons.

It's not quite "very slight", but it isn't great ;-)

That said, I've become quite annoyed with the whole thing, and am
seriously thinking of building a desk wiring harness that has a single
(possibly 20VAC) supply, with plug in (eg: 1/4" phone jacks
or somesuch) adapters that contain the different voltage/AC-DC/plug
converters.

You can combine DC supplies, but be sure to consider which side is
grounded.
--
54 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[Mark Lloyd]

On 31 Oct 2006 15:54:35 -0800, "hallerb@aol.com" <hallerb@aol.com>
wrote:

I have done a lot of this, changed plugs oon them too.

What the government should do is mandate a standard, 12 volts AC with
standard plug

have the device convert it to DC if necessary, change the voltage
whatever.

since AC has no polarity and a standard plugwe would cut down n the
amount of trash, and simplify things.

It would.

If we has 12VAC power available everywhere, the adapters could be much
smaller (or even built in to equipment).

There's a lot of things that could use standards, including button
cells (used in watches, hearing aids, etc...).
--
54 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[Mark Lloyd]

On Tue, 31 Oct 2006 21:40:07 -0500, mm <NOPSAMmm2005@bigfoot.com>
wrote:

On 31 Oct 2006 15:54:35 -0800, "hallerb@aol.com" <hallerb@aol.com
wrote:

I have done a lot of this, changed plugs oon them too.

What the government should do is mandate a standard, 12 volts AC with
standard plug

have the device convert it to DC if necessary, change the voltage
whatever.

since AC has no polarity and a standard plugwe would cut down n the
amount of trash, and simplify things.

What gets me are all the small transformers running all the time using
a little bit of current each. Even when the transformer is inside the
radio, etc, and the on/off swtich could turn off the whole thing, it
never does. Only the secondary.

Equipment used to have hard power switches (that disconnected
everything). Now, the power supply needs to stay active to supply
power to things like clocks (even when you don't need a clock there),
memories, electronic "power" switches, and remote controls. Some even
have a light that glows all the time the equipment is "off".

They should have everything run on 12 volts or whatever, and have one
12 volt transformer at the fuse box that runs everything, with outlets
in every room for 12 volts AC and whatever DC. Heck, they should use
the doorbell transformer for all of this.

How much current capacity? That system may be impractical, but you
could use ONE transformer instead of several with your computer.
--
54 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[Mark Lloyd]

On Wed, 01 Nov 2006 10:38:23 -0500, Goedjn <prose@mail.uri.edu> wrote:

On Tue, 31 Oct 2006 21:40:07 -0500, mm <NOPSAMmm2005@bigfoot.com
wrote:

On 31 Oct 2006 15:54:35 -0800, "hallerb@aol.com" <hallerb@aol.com
wrote:

I have done a lot of this, changed plugs oon them too.

What the government should do is mandate a standard, 12 volts AC with
standard plug

have the device convert it to DC if necessary, change the voltage
whatever.

since AC has no polarity and a standard plugwe would cut down n the
amount of trash, and simplify things.

What gets me are all the small transformers running all the time using
a little bit of current each. Even when the transformer is inside the
radio, etc, and the on/off swtich could turn off the whole thing, it
never does. Only the secondary.

They should have everything run on 12 volts or whatever, and have one
12 volt transformer at the fuse box that runs everything, with outlets
in every room for 12 volts AC and whatever DC. Heck, they should use
the doorbell transformer for all of this.

Power-over-ethernet, 24V, 12Watts. (thus 1/2 amp?)

That wouldn't go very far toward eliminating the cluster of wall warts
behind the computer.
--
54 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[mm]

On Wed, 01 Nov 2006 15:38:53 -0600, Mark Lloyd
<mlloyd@xmail.com10.invalid> wrote:

On Tue, 31 Oct 2006 21:40:07 -0500, mm <NOPSAMmm2005@bigfoot.com
wrote:

On 31 Oct 2006 15:54:35 -0800, "hallerb@aol.com" <hallerb@aol.com
wrote:

I have done a lot of this, changed plugs oon them too.

What the government should do is mandate a standard, 12 volts AC with
standard plug

have the device convert it to DC if necessary, change the voltage
whatever.

since AC has no polarity and a standard plugwe would cut down n the
amount of trash, and simplify things.

What gets me are all the small transformers running all the time using
a little bit of current each. Even when the transformer is inside the
radio, etc, and the on/off swtich could turn off the whole thing, it
never does. Only the secondary.


Equipment used to have hard power switches (that disconnected
everything). Now, the power supply needs to stay active to supply
power to things like clocks (even when you don't need a clock there),
memories, electronic "power" switches, and remote controls. Some even
have a light that glows all the time the equipment is "off".

I"m sure that accounts for a lot of things, but I've seen a lot of
other things where none of that existed. Just one example, my
wireless speakers don't have a clock, remote control, memory, or a
light, and one needs to turn a knob to turn the speaker on. Yet it
uses a wall wart that is on whenever it is plugged in. I unplug mine.
(I have one only in the bathroom, bedroom, kitchen, and basement, so
that I can listen to web radio wherever I am. But I only do that 1 to
5 hours a month. I don't need 4 wall warts runing 720 hours a month
for my 1 to 5 hours.)

They should have everything run on 12 volts or whatever, and have one
12 volt transformer at the fuse box that runs everything, with outlets
in every room for 12 volts AC and whatever DC. Heck, they should use
the doorbell transformer for all of this.

How much current capacity?

I don't know. Too many other projects ahead of it, but I also need
the manufactures to agree on a voltage and current direction.

That system may be impractical, but you
could use ONE transformer instead of several with your computer.

I think the printer, scanner, and speaker take different voltages, but
for my computer, I bought (used for only 2 or 3 dollars) a box that
goes under the monitor and has 4 switches plus a master switch. I use
one for the printer, one for the speakers, one for the wireless
speaker transmitter, and one is still empty. Because of space
limitations, only every second outlet can be used for a wallwart,
unless I need more, in which case I'll use a short extension cord.

 

[mm]

On 1 Nov 2006 04:39:21 -0800, "willisl@iupui.edu" <willisl@iupui.edu>
wrote:

Wow! Thanks to all for the responses. It looks as though a little
mixing and matching is OK with these adapters if one knows how to use a
voltmeter. I guess I'll give it a try.

With a volt-ohmmeter, all things are possible.

Thanks again.

Lynn Willis
Indianapolis

 

[Mark Lloyd]

On Wed, 01 Nov 2006 22:13:22 -0500, mm <NOPSAMmm2005@bigfoot.com>
wrote:

On Wed, 01 Nov 2006 15:38:53 -0600, Mark Lloyd
mlloyd@xmail.com10.invalid> wrote:

On Tue, 31 Oct 2006 21:40:07 -0500, mm <NOPSAMmm2005@bigfoot.com
wrote:

On 31 Oct 2006 15:54:35 -0800, "hallerb@aol.com" <hallerb@aol.com
wrote:

I have done a lot of this, changed plugs oon them too.

What the government should do is mandate a standard, 12 volts AC with
standard plug

have the device convert it to DC if necessary, change the voltage
whatever.

since AC has no polarity and a standard plugwe would cut down n the
amount of trash, and simplify things.

What gets me are all the small transformers running all the time using
a little bit of current each. Even when the transformer is inside the
radio, etc, and the on/off swtich could turn off the whole thing, it
never does. Only the secondary.


Equipment used to have hard power switches (that disconnected
everything). Now, the power supply needs to stay active to supply
power to things like clocks (even when you don't need a clock there),
memories, electronic "power" switches, and remote controls. Some even
have a light that glows all the time the equipment is "off".

I"m sure that accounts for a lot of things, but I've seen a lot of
other things where none of that existed. Just one example, my
wireless speakers don't have a clock, remote control, memory, or a
light, and one needs to turn a knob to turn the speaker on. Yet it
uses a wall wart that is on whenever it is plugged in.
I unplug mine. (I have one only in the bathroom, bedroom, kitchen, and basement, so
that I can listen to web radio wherever I am. But I only do that 1 to
5 hours a month. I don't need 4 wall warts runing 720 hours a month
for my 1 to 5 hours.)

You can always use a switch cord. That's like an extension cord, but
with both male and female ends at the same end and a switch at the
other. I've seen them at the local Lowe's (no grounding cords though).
I am using several of those cords now, to have switches in more
convenient places.

They should have everything run on 12 volts or whatever, and have one
12 volt transformer at the fuse box that runs everything, with outlets
in every room for 12 volts AC and whatever DC. Heck, they should use
the doorbell transformer for all of this.

How much current capacity?

I don't know. Too many other projects ahead of it, but I also need
the manufactures to agree on a voltage and current direction.

That system may be impractical, but you
could use ONE transformer instead of several with your computer.

I think the printer, scanner, and speaker take different voltages, but
for my computer, I bought (used for only 2 or 3 dollars) a box that
goes under the monitor and has 4 switches plus a master switch. I use
one for the printer, one for the speakers, one for the wireless
speaker transmitter, and one is still empty. Because of space
limitations, only every second outlet can be used for a wallwart,
unless I need more, in which case I'll use a short extension cord.

The biggest "power strip hog" I've seen is my kill-a-watt meter. It's
plugged into a power strip now (getting ready for checking holiday
lights. I use so many that it's important to keep track of electrical
load) , and it blocks FOUR additional outlets. That isn't a problem
right now, but it could be someday.
--
53 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[Mark Lloyd]

On Wed, 01 Nov 2006 22:17:33 -0500, mm <NOPSAMmm2005@bigfoot.com>
wrote:

On 1 Nov 2006 04:39:21 -0800, "willisl@iupui.edu" <willisl@iupui.edu
wrote:


Wow! Thanks to all for the responses. It looks as though a little
mixing and matching is OK with these adapters if one knows how to use a
voltmeter. I guess I'll give it a try.

With a volt-ohmmeter, all things are possible.

Thanks again.

Lynn Willis
Indianapolis

I have one 12VDC 1A power supply that is connected to 2 separate
cameras. This is a regulated supply, which was needed to reduce noise
in the video output of the cameras.

If one of them needed a different voltage, it would be possible to use
diodes (consider current here too, diodes have current as well as
voltage ratings) to drop the voltage (2 diodes in series give about
1.5V drop). If the devices have a common ground (as those cameras do),
that needs to be considered when powering multiple devices with 1
adapter.
--
53 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[mm]

On Thu, 02 Nov 2006 10:28:10 -0600, Mark Lloyd
<mlloyd@xmail.com10.invalid> wrote:

I"m sure that accounts for a lot of things, but I've seen a lot of
other things where none of that existed. Just one example, my
wireless speakers don't have a clock, remote control, memory, or a
light, and one needs to turn a knob to turn the speaker on. Yet it
uses a wall wart that is on whenever it is plugged in.
I unplug mine. (I have one only in the bathroom, bedroom, kitchen, and basement, so
that I can listen to web radio wherever I am. But I only do that 1 to
5 hours a month. I don't need 4 wall warts runing 720 hours a month
for my 1 to 5 hours.)


You can always use a switch cord. That's like an extension cord, but
with both male and female ends at the same end and a switch at the
other. I've seen them at the local Lowe's (no grounding cords though).
I am using several of those cords now, to have switches in more
convenient places.

That's a good idea. I use one for the fan on the file cabinet, so I
don't have to get up when I'm on the computer.

And I used to use one to turn the tv on and off when I was in bed.
Then I got one with remote control that forgot something, maybe the
station list, when unplugged. The one there now might well not
forget, so I should go back to using the wired switch, which is easier
to find and easier to use than the remote.

Remove NOPSAM to email me..

 

[Mark Lloyd]

On Thu, 02 Nov 2006 15:00:36 -0500, mm <NOPSAMmm2005@bigfoot.com>
wrote:

On Thu, 02 Nov 2006 10:28:10 -0600, Mark Lloyd
mlloyd@xmail.com10.invalid> wrote:


I"m sure that accounts for a lot of things, but I've seen a lot of
other things where none of that existed. Just one example, my
wireless speakers don't have a clock, remote control, memory, or a
light, and one needs to turn a knob to turn the speaker on. Yet it
uses a wall wart that is on whenever it is plugged in.
I unplug mine. (I have one only in the bathroom, bedroom, kitchen, and basement, so
that I can listen to web radio wherever I am. But I only do that 1 to
5 hours a month. I don't need 4 wall warts runing 720 hours a month
for my 1 to 5 hours.)


You can always use a switch cord. That's like an extension cord, but
with both male and female ends at the same end and a switch at the
other. I've seen them at the local Lowe's (no grounding cords though).
I am using several of those cords now, to have switches in more
convenient places.

That's a good idea. I use one for the fan on the file cabinet, so I
don't have to get up when I'm on the computer.

And I used to use one to turn the tv on and off when I was in bed.
Then I got one with remote control that forgot something, maybe the
station list, when unplugged. The one there now might well not
forget, so I should go back to using the wired switch, which is easier
to find and easier to use than the remote.

A lot of TVs forget to be on once power has been removed. Anyone using
hard power switches or home automation would be interested in which
TVs don't have this problem. I have 2 Magnavox sets and a Sylvania
that don't. Both are 15-inch LCD TVs.

Remove NOPSAM to email me..

I know this is not email (and wouldn't suggest otherwise).
--
53 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[PeterD]

On Thu, 02 Nov 2006 17:14:58 -0600, Mark Lloyd
<mlloyd@xmail.com10.invalid> wrote:

On Thu, 02 Nov 2006 15:00:36 -0500, mm <NOPSAMmm2005@bigfoot.com
wrote:

On Thu, 02 Nov 2006 10:28:10 -0600, Mark Lloyd
mlloyd@xmail.com10.invalid> wrote:

That's a good idea. I use one for the fan on the file cabinet, so I
don't have to get up when I'm on the computer.

And I used to use one to turn the tv on and off when I was in bed.
Then I got one with remote control that forgot something, maybe the
station list, when unplugged. The one there now might well not
forget, so I should go back to using the wired switch, which is easier
to find and easier to use than the remote.


A lot of TVs forget to be on once power has been removed. Anyone using
hard power switches or home automation would be interested in which
TVs don't have this problem. I have 2 Magnavox sets and a Sylvania
that don't. Both are 15-inch LCD TVs.

I've found that most (smaller) LCD TVs seem to have 'better' memory
when power is interrupted.

Remove NOPSAM to email me..

I know this is not email (and wouldn't suggest otherwise).
--
53 days until the winter solstice celebration

Ah, yes but will the solstice run on a wall wart? <vbg!>

Me, I'll wait for spring...

 

[Chris Lewis]

According to Mark Lloyd <mlloyd@xmail.com10.invalid>:

I have one 12VDC 1A power supply that is connected to 2 separate
cameras. This is a regulated supply, which was needed to reduce noise
in the video output of the cameras.

If one of them needed a different voltage, it would be possible to use
diodes (consider current here too, diodes have current as well as
voltage ratings) to drop the voltage (2 diodes in series give about
1.5V drop). If the devices have a common ground (as those cameras do),
that needs to be considered when powering multiple devices with 1
adapter.

Diodes in series is a reasonable regulator, but it might not
be good enough if the current through them varies a lot.

In which case, something like a three lead regulator would be
better. But, they usually need more than 1.2V of headroom to
operate.

[That was what I was envisaging for my "universal wallwart strip".
A series of jacks at, say, 20VAC, with things that plug in that have
combinations of bridge rectifiers and regulator chips.]
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

 

[Mark Lloyd]

On Fri, 03 Nov 2006 21:09:20 -0000, clewis@nortelnetworks.com (Chris
Lewis) wrote:

According to Mark Lloyd <mlloyd@xmail.com10.invalid>:
I have one 12VDC 1A power supply that is connected to 2 separate
cameras. This is a regulated supply, which was needed to reduce noise
in the video output of the cameras.

If one of them needed a different voltage, it would be possible to use
diodes (consider current here too, diodes have current as well as
voltage ratings) to drop the voltage (2 diodes in series give about
1.5V drop). If the devices have a common ground (as those cameras do),
that needs to be considered when powering multiple devices with 1
adapter.

Diodes in series is a reasonable regulator, but it might not
be good enough if the current through them varies a lot.

2 diodes in series is exactly what you have with a full-wave bridge
rectifier. I haven't heard of voltage drop varying with current.
Perhaps you could explain.

In which case, something like a three lead regulator would be
better. But, they usually need more than 1.2V of headroom to
operate.

A 78Lxx would be good if you don't need much current. Those are no
bigger than transistors.

BTW, I'm using a 78L05 to power a MAX233 (RS232 interface) to control
holiday lights (it worked fine for Halloween). The input to it is a
9VDC wall-wart. I can give more information on this if anybody cares.

It could be easier to use the regulator if you had to drop the voltage
a lot (too many diodes).

[That was what I was envisaging for my "universal wallwart strip".
A series of jacks at, say, 20VAC, with things that plug in that have
combinations of bridge rectifiers and regulator chips.]

Don't forget the filter capacitors (for DC).
--
52 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy

 

[Tony Hwang]

Mark Lloyd wrote:

On Fri, 03 Nov 2006 21:09:20 -0000, clewis@nortelnetworks.com (Chris
Lewis) wrote:


According to Mark Lloyd <mlloyd@xmail.com10.invalid>:

I have one 12VDC 1A power supply that is connected to 2 separate
cameras. This is a regulated supply, which was needed to reduce noise
in the video output of the cameras.

If one of them needed a different voltage, it would be possible to use
diodes (consider current here too, diodes have current as well as
voltage ratings) to drop the voltage (2 diodes in series give about
1.5V drop). If the devices have a common ground (as those cameras do),
that needs to be considered when powering multiple devices with 1
adapter.

Diodes in series is a reasonable regulator, but it might not
be good enough if the current through them varies a lot.



2 diodes in series is exactly what you have with a full-wave bridge
rectifier. I haven't heard of voltage drop varying with current.
Perhaps you could explain.


In which case, something like a three lead regulator would be
better. But, they usually need more than 1.2V of headroom to
operate.



A 78Lxx would be good if you don't need much current. Those are no
bigger than transistors.

BTW, I'm using a 78L05 to power a MAX233 (RS232 interface) to control
holiday lights (it worked fine for Halloween). The input to it is a
9VDC wall-wart. I can give more information on this if anybody cares.

It could be easier to use the regulator if you had to drop the voltage
a lot (too many diodes).


[That was what I was envisaging for my "universal wallwart strip".
A series of jacks at, say, 20VAC, with things that plug in that have
combinations of bridge rectifiers and regulator chips.]


Don't forget the filter capacitors (for DC).

 

[Tony Hwang]

Mark Lloyd wrote:

On Fri, 03 Nov 2006 21:09:20 -0000, clewis@nortelnetworks.com (Chris
Lewis) wrote:


According to Mark Lloyd <mlloyd@xmail.com10.invalid>:

I have one 12VDC 1A power supply that is connected to 2 separate
cameras. This is a regulated supply, which was needed to reduce noise
in the video output of the cameras.

If one of them needed a different voltage, it would be possible to use
diodes (consider current here too, diodes have current as well as
voltage ratings) to drop the voltage (2 diodes in series give about
1.5V drop). If the devices have a common ground (as those cameras do),
that needs to be considered when powering multiple devices with 1
adapter.

Diodes in series is a reasonable regulator, but it might not
be good enough if the current through them varies a lot.



2 diodes in series is exactly what you have with a full-wave bridge
rectifier. I haven't heard of voltage drop varying with current.
Perhaps you could explain.
Hi,
Usual Si diode has a typical voltage drop of 0.2V across it's junction.

If you put them in series it'll be multiple of 0.2. If current
increases, you do the math acoding to the Ohm's law. Also regulator
typically comes in two different flavors. Series or shunt type.

 

[Art Todesco]

Tony Hwang wrote:

Mark Lloyd wrote:

On Fri, 03 Nov 2006 21:09:20 -0000, clewis@nortelnetworks.com (Chris
Lewis) wrote:


According to Mark Lloyd <mlloyd@xmail.com10.invalid>:

I have one 12VDC 1A power supply that is connected to 2 separate
cameras. This is a regulated supply, which was needed to reduce noise
in the video output of the cameras.


If one of them needed a different voltage, it would be possible to use
diodes (consider current here too, diodes have current as well as
voltage ratings) to drop the voltage (2 diodes in series give about
1.5V drop). If the devices have a common ground (as those cameras do),
that needs to be considered when powering multiple devices with 1
adapter.


Diodes in series is a reasonable regulator, but it might not
be good enough if the current through them varies a lot.



2 diodes in series is exactly what you have with a full-wave bridge
rectifier. I haven't heard of voltage drop varying with current.
Perhaps you could explain.
Hi,

Usual Si diode has a typical voltage drop of 0.2V across it's junction.
If you put them in series it'll be multiple of 0.2. If current
increases, you do the math acoding to the Ohm's law. Also regulator
typically comes in two different flavors. Series or shunt type.
Actually, Silicon diodes have a drop of

0.7 volt; Germanium diodes have
a 0.2 volt drop.

 

[Chris Lewis]

According to Art Todesco <actodesco@yahoo.com>:

Tony Hwang wrote:
Usual Si diode has a typical voltage drop of 0.2V across it's junction.
If you put them in series it'll be multiple of 0.2. If current
increases, you do the math acoding to the Ohm's law. Also regulator
typically comes in two different flavors. Series or shunt type.
Actually, Silicon diodes have a drop of
0.7 volt; Germanium diodes have
a 0.2 volt drop.

Heh, Si diode forward drop is usually quoted in all the material I've
dealt with over the years as .6V ;-)

Forward drop in a diode is highly non-linear relative to current flow,
and ohms law doesn't apply.

Forward drop voltage tends to hit .6V at quite low currents, and
then very slowly increase to a volt or more near max current for the diode.

A diode does act as regulator, but they don't regulate that well with
widely varying currents. Depends on how accurate the voltage regulation
needs to be.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.