OT: Power Supplies
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Posts: 46,084
Hello:
I appologize for this post being a little off topic however I'm
confident that a member of this group has the ability to quickly
answer my query. I have a need for a DC power supply somewhere in
the 80-110 VDC range. I have scowered the internet for info
regarding this and have found plenty of examples for AC-DC power
supply's using a transformer, bridge rectifier, and capacitor (along
with various fuses and the like). What I'm interested in is is it
possible to construct a power supply without the transformer and
what the voltage of the resulting power supply would be. I'd also be
interested in being directed to some entry level education on power
supplies if anyone has any recomendations.
Thank You
Aaron Nielsen
I appologize for this post being a little off topic however I'm
confident that a member of this group has the ability to quickly
answer my query. I have a need for a DC power supply somewhere in
the 80-110 VDC range. I have scowered the internet for info
regarding this and have found plenty of examples for AC-DC power
supply's using a transformer, bridge rectifier, and capacitor (along
with various fuses and the like). What I'm interested in is is it
possible to construct a power supply without the transformer and
what the voltage of the resulting power supply would be. I'd also be
interested in being directed to some entry level education on power
supplies if anyone has any recomendations.
Thank You
Aaron Nielsen
Comments
to isolate you from mains, a bridge rectifier, and a bunch of filter caps.
This will get you ~110VDC. From there, you can set up a switching reg. or
whatever to bring the voltage to where you need it. In fact, you could prob.
run the switcher right off of 110VAC, after it goes through the isolation
transformer.
Investigate it some more, though... I'm no expert.
- Robert
Original Message
From: "Aaron" <snazzyguy2@y...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, August 05, 2003 5:55 PM
Subject: [noparse][[/noparse]basicstamps] OT: Power Supplies
> Hello:
>
> I appologize for this post being a little off topic however I'm
> confident that a member of this group has the ability to quickly
> answer my query. I have a need for a DC power supply somewhere in
> the 80-110 VDC range. I have scowered the internet for info
> regarding this and have found plenty of examples for AC-DC power
> supply's using a transformer, bridge rectifier, and capacitor (along
> with various fuses and the like). What I'm interested in is is it
> possible to construct a power supply without the transformer and
> what the voltage of the resulting power supply would be. I'd also be
> interested in being directed to some entry level education on power
> supplies if anyone has any recomendations.
>
> Thank You
> Aaron Nielsen
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
You do not mention how much current you need.
The 2 biggest reasons to use a transformer is to get the proper voltage, and
Safety.
The transformer will isolate the circuit from the Main AC power. Any short or
marginal circuit component can over heat, burn, catch fire, or cause a deadly
shock.
Remember there are more lawyers listed in the phone book than physicians.
If you are using a low power device then spend the $$ and buy an isolation
transformer.
If it is a high current circuit then you really need to have an experienced
electrical engineer look it over. It only takes once to get blasted to
oblivion.
Im sure this is not the answer you were looking for, but it is good advice
for using mains powered circuits.
Alan Bradford
Plasma Technologies
[noparse][[/noparse]Non-text portions of this message have been removed]
There are all sorts of transformerless power supplies out there. A lot
depends on what you are looking for. What kind of a device are you running
and what current do you need? For example, I made a power supply for a Nixie
tube from a disposable camera flash unit, but I only needed 1-2mA at 170VDC.
But it ran on a battery!
However, any transformerless design that hooks up to the mains 110VAC has
inherent dangers. Transformers limit current and are safer. If you can find
the room for a transformer, and they make some pretty small ones, it's
probably the way to go. Remember the max voltage of a transformer will be
1.4 times the rated voltage, so plan accordingly. If you need a lot of
current, make sure of what you are doing, you are dealing with potentially
lethal voltages.
Jonathan
www.madlabs.info
Original Message
From: "Aaron" <snazzyguy2@y...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, August 05, 2003 4:55 PM
Subject: [noparse][[/noparse]basicstamps] OT: Power Supplies
> Hello:
>
> I appologize for this post being a little off topic however I'm
> confident that a member of this group has the ability to quickly
> answer my query. I have a need for a DC power supply somewhere in
> the 80-110 VDC range. I have scowered the internet for info
> regarding this and have found plenty of examples for AC-DC power
> supply's using a transformer, bridge rectifier, and capacitor (along
> with various fuses and the like). What I'm interested in is is it
> possible to construct a power supply without the transformer and
> what the voltage of the resulting power supply would be. I'd also be
> interested in being directed to some entry level education on power
> supplies if anyone has any recomendations.
>
> Thank You
> Aaron Nielsen
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
First, let me stress safety when dealing with high
voltages. Not to lecture, but these voltages can be
lethal and a capacitor charged to 110VDC can blow a
small screwdriver into pieces if it's shorted.
My first suggestion would be to look on eBay for a
Sorensen power supply. I've seen 0 to 120 VDC, fully
adjustable, laboratory grade, with current capacity
from 0 to 8 amps for about the $300 range. A little
pricey, but very nice and safer than piecing one
together.
A cheaper suggestion, but far less safe would be to
use a variable transformer (still a tranformer, but it
has a large knob to adjust the AC output voltage -
check out Jameco's 121275 unit) to derive 0 to 120VAC,
then rectify and filter the voltage to get 0 to
160VDC. (You end up with about 160VDC because VDC =
VAC RMS * 1.414)
For some good electronics basics, including power
supplies, and some great circuit ideas, I recommend
Forrest Mims Engineer's Notebook. It's about $14 on
Amazon.com.
Be Careful,
Dr. Diode
--- Aaron <snazzyguy2@y...> wrote:
> Hello:
>
> I appologize for this post being a little off topic
> however I'm
> confident that a member of this group has the
> ability to quickly
> answer my query. I have a need for a DC power supply
> somewhere in
> the 80-110 VDC range. I have scowered the internet
> for info
> regarding this and have found plenty of examples for
> AC-DC power
> supply's using a transformer, bridge rectifier, and
> capacitor (along
> with various fuses and the like). What I'm
> interested in is is it
> possible to construct a power supply without the
> transformer and
> what the voltage of the resulting power supply would
> be. I'd also be
> interested in being directed to some entry level
> education on power
> supplies if anyone has any recomendations.
>
> Thank You
> Aaron Nielsen
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed.
> Text in the Subject and Body of the message will be
> ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com
most (if not all) variable transformers are Variacs of some sort, which
don't offer any isolation between the inputs and outputs. They do buck and
boost modes from a single coil with a variable tap. If you then feed the
output of such a unit into a full-wave bridge rectifier attempting to make
DC, the whole filter capacitor assembly will be riding on a 120 AC sine
wave, which is about as dangerous as it gets.
DD's remarks on safety cannot be stressed enough. While messing with the
relatively low voltages and currents from a wall-wart derived supply cab be
pretty benign, once you attach a circuit directly to a 120 Volt 20 Amp
source, any real failure will be catastrophic. And I'm talking about
capacitors that blow up like small bombs, blowing aluminum confetti all over
your circuit (and your face), wires that vaporize in a cloud of superheated
molten copper, parts welded together, large fires, etc.... And I'm not
writing about this from a textbook, but from 40 years of working with
electronics in general.
Let's be careful out there...
Mike Sokol
www.modernrecording.com
mikes@m...
Original Message
From: "PH" <drdiode2002@y...>
To: <basicstamps@yahoogroups.com>
Sent: Saturday, August 09, 2003 11:53 AM
Subject: Re: [noparse][[/noparse]basicstamps] OT: Power Supplies
> Hi Aaron,
>
> First, let me stress safety when dealing with high
> voltages. Not to lecture, but these voltages can be
> lethal and a capacitor charged to 110VDC can blow a
> small screwdriver into pieces if it's shorted.
>
> My first suggestion would be to look on eBay for a
> Sorensen power supply. I've seen 0 to 120 VDC, fully
> adjustable, laboratory grade, with current capacity
> from 0 to 8 amps for about the $300 range. A little
> pricey, but very nice and safer than piecing one
> together.
>
> A cheaper suggestion, but far less safe would be to
> use a variable transformer (still a tranformer, but it
> has a large knob to adjust the AC output voltage -
> check out Jameco's 121275 unit) to derive 0 to 120VAC,
> then rectify and filter the voltage to get 0 to
> 160VDC. (You end up with about 160VDC because VDC =
> VAC RMS * 1.414)
>
> For some good electronics basics, including power
> supplies, and some great circuit ideas, I recommend
> Forrest Mims Engineer's Notebook. It's about $14 on
> Amazon.com.
>
> Be Careful,
> Dr. Diode
> --- Aaron <snazzyguy2@y...> wrote:
> > Hello:
> >
> > I appologize for this post being a little off topic
> > however I'm
> > confident that a member of this group has the
> > ability to quickly
> > answer my query. I have a need for a DC power supply
> > somewhere in
> > the 80-110 VDC range. I have scowered the internet
> > for info
> > regarding this and have found plenty of examples for
> > AC-DC power
> > supply's using a transformer, bridge rectifier, and
> > capacitor (along
> > with various fuses and the like). What I'm
> > interested in is is it
> > possible to construct a power supply without the
> > transformer and
> > what the voltage of the resulting power supply would
> > be. I'd also be
> > interested in being directed to some entry level
> > education on power
> > supplies if anyone has any recomendations.
> >
> > Thank You
> > Aaron Nielsen
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed.
> > Text in the Subject and Body of the message will be
> > ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! SiteBuilder - Free, easy-to-use web site design software
> http://sitebuilder.yahoo.com
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
> Hello:
>
> I appologize for this post being a little off topic however I'm
> confident that a member of this group has the ability to quickly
> answer my query. I have a need for a DC power supply somewhere in
> the 80-110 VDC range. I have scowered the internet for info
> regarding this and have found plenty of examples for AC-DC power
> supply's using a transformer, bridge rectifier, and capacitor
(along
> with various fuses and the like). What I'm interested in is is it
> possible to construct a power supply without the transformer and
> what the voltage of the resulting power supply would be. I'd also
be
> interested in being directed to some entry level education on power
> supplies if anyone has any recomendations.
What you are talking about is a switcher type of power supply. This
will have huge ripple problems and the inductors used to remove the
ripple are often as large as a transformer. or you will need to
design the caps to remove the frequencies in the ranges you are
worried about.
it would seem that you are not after low power or a simple resistor
network would offer high voltage signals, but low power or high heat.
once you start to get away from the self regulating effects of the
transformer, you need to compensate with active circuit components.
but, if you don't need high power, get one of those Torche lamps.
rated for around 300 watts. it has a tiny circuit to regulate
voltage into the lamp.
The problem with not using active regulation is that you are subject
to power line glitches and spikes.
A word of caution - tie stuff to the bench when working. small
circuit boards can flip over from the twist of the wire. (Don't ask
me how I know, but the scar has healed nicely.)
>
> Thank You
> Aaron Nielsen
and design information about power supplies and other electronics. Many
other publications are also available there.
jim
http://www.geocities.com/jimforkin2003/
Original Message
From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=iYqb9DdD-wRNZUjlCRYv8ton7jVgc_87vbz65CI6J2C646FvLk_RTMuL5CRjjWSqz23zsnnKEqedVQ0]davemucha@j...[/url
Sent: Saturday, August 09, 2003 12:30 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: OT: Power Supplies
--- In basicstamps@yahoogroups.com, "Aaron" <snazzyguy2@y...> wrote:
> Hello:
>
> I appologize for this post being a little off topic however I'm
> confident that a member of this group has the ability to quickly
> answer my query. I have a need for a DC power supply somewhere in
> the 80-110 VDC range. I have scowered the internet for info
> regarding this and have found plenty of examples for AC-DC power
> supply's using a transformer, bridge rectifier, and capacitor
(along
> with various fuses and the like). What I'm interested in is is it
> possible to construct a power supply without the transformer and
> what the voltage of the resulting power supply would be. I'd also
be
> interested in being directed to some entry level education on power
> supplies if anyone has any recomendations.
What you are talking about is a switcher type of power supply. This
will have huge ripple problems and the inductors used to remove the
ripple are often as large as a transformer. or you will need to
design the caps to remove the frequencies in the ranges you are
worried about.
it would seem that you are not after low power or a simple resistor
network would offer high voltage signals, but low power or high heat.
once you start to get away from the self regulating effects of the
transformer, you need to compensate with active circuit components.
but, if you don't need high power, get one of those Torche lamps.
rated for around 300 watts. it has a tiny circuit to regulate
voltage into the lamp.
The problem with not using active regulation is that you are subject
to power line glitches and spikes.
A word of caution - tie stuff to the bench when working. small
circuit boards can flip over from the twist of the wire. (Don't ask
me how I know, but the scar has healed nicely.)
>
> Thank You
> Aaron Nielsen
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/