magnetic field

[Sam Goldwasser]

Uncle Al <UncleAl0@hate.spam.net> writes:

Mark Fergerson wrote:

Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:


Sam Goldwasser wrote:


Dirk Bruere at Neopax <dirk@neopax.com> writes:


rgregoryclark@yahoo.com wrote:



I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?

Quartz lens?


The problem isn't the lens material as much as the beam quality. It
will be hard to focus the typical home-built N2 laser's output to a
very small spot.

Depends on the length of the laser cavity I assume, since its single pass.


More than that. It depends on the mode structure of the beam.

I was going to mention mirror quality and how they're positioned
vs. cavity proportions...

Superradiant nitrogen lasers have messy output, as such or one pass
with a rear mirror. The cavity is irrelevant. The output is not
coherent. You might as well try focusing a flashbulb to a few microns
image radius.

Well, it's not quite that bad. Most of the light is confined to the
area of the the long narrow discharge gap.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

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[Sam Goldwasser]

Baugh <baconbaugh@charter.net> writes:

Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:

rgregoryclark@yahoo.com wrote:


I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?

Quartz lens?
The problem isn't the lens material as much as the beam quality. It
will be
hard to focus the typical home-built N2 laser's output to a very small spot.


Cannot you by placing the lens far enough away from the laser obtain a
better focus? The distance will correlate off-line output with lateral
displacement. A lens of sufficient quality and wide enough for the
spread beam will then redirect more accurately to the focus.

Think of it in terms of the focused image for the distance to the laser
will move closer to the focus from infinity as you move the lens farther
away. (Again assuming no spherical aberation in the lens.)

You're not imaging the output aperture of the laser, you're trying to focus
the beam from the laser. As such, how far away you are isn't very relevant.

However, if you're implying that a large f-number lens is better. Sure.

I'm not sure I'd go so far as to say they aren't coherent asn other posts
have stated, but there is a most one bounc from a rear mirror (which isn't
essential) and the light makes at most two passes through the laser. This
doesn't set up a nice mode structure. As everyone's stated, it is messy.

Maybe he'd be better off finding a surplus excimer laser.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

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Important: Anything sent to the email address in the message header above is
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[Harveyx]

"Sam Goldwasser" <sam@saul.cis.upenn.edu> wrote in message
news:6wwtq5qld9.fsf@saul.cis.upenn.edu...

Uncle Al <UncleAl0@hate.spam.net> writes:

Mark Fergerson wrote:

Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:


Sam Goldwasser wrote:


Dirk Bruere at Neopax <dirk@neopax.com> writes:


rgregoryclark@yahoo.com wrote:



I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the
range of
say a few hundred microns wide?

Quartz lens?


The problem isn't the lens material as much as the beam quality. It
will be hard to focus the typical home-built N2 laser's output to a
very small spot.

Depends on the length of the laser cavity I assume, since its single
pass.


More than that. It depends on the mode structure of the beam.

I was going to mention mirror quality and how they're positioned
vs. cavity proportions...

Superradiant nitrogen lasers have messy output, as such or one pass
with a rear mirror. The cavity is irrelevant. The output is not
coherent. You might as well try focusing a flashbulb to a few microns
image radius.

Well, it's not quite that bad. Most of the light is confined to the
area of the the long narrow discharge gap.

Uncle Al overstates his case a bit.
Why dont we try numbers instead of words..............
Forget 'mode structure' for most N2 lasers, there is essentially none, they
are single pass. But neither is it *quite* 'a flasbulb'.
To a pretty good approximation crude nitrogen laseers have a divergence
which is about d/L where d is the 'tube' (discharge, often transverse)
diameter & L the length.
If you focus it with focal length F your spot diameter is just F*d/L

So, if you want 0.1mm, d is maybe 5mm & L maybe 200mm you would need a 4mm
focal length, which is operating at F~0,8
You might get a UV transparent microscope objective (at a price) that gets
near that, but its pretty challenging to put it mildly.

With a longer, thinner laser, and relax it to 'a few' hundred um spot, and
you would get into just about achievable regimes.
With longer focal lengths, the F number falls, & aberrations are rapidly
less of an issue - its rather far from diffraction limited!
Lens UV transparency at 337nm is an issue, especially for a thick short
focus lens.

Harvey

 

[Harveyx]

"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:42825BEC.4DBA557E@hate.spam.net...

rgregoryclark@yahoo.com wrote:

I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?

337 nm. Fused silica, alkali halide, or alkaline earth fluoride
lens. A meniscus lens is preferred to lessen aberrations.

For roughly collimated to focus, a plano-convex lens is near optimum for
n~1.5; thats why they are so commonly available.
Put it the right way round, students often dont! (The exact solution is
indeed a near plano/vex meniscus; but the plano vex is what gets used.)
(Meniscus is optimum for higher index material, such a Ge in the IR.)
Silica or CaF2 would be the usual, available choices, (LiF & MgF2 also.) The
chlorides & bromides are OK in the IR where scatter is much less critical,
pain in the UV, & often form colour centres under UV irradiation, dependent
on the source.

You need a *UV grade* silica.

Down to

microns is gonna take some work - superradiant lasers are not coherent
and you'll need a large diopter rating (thick lenses are problems on
several fronts). I doubt Fresnel or binary optics configurations can
pull it off, especially if you need imaging in addition to
concentration.

See rough sum in the other post.
Basically I agree, but it is just about 'do-able'

Harvey

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

 

[Pooh Bear]

Keith Williams wrote:

In article <4281BA04.5F1D2E6E@hotmail.com>,
rabbitsfriendsandrelations@hotmail.com says...
keith wrote:

On Sun, 08 May 2005 16:39:55 -0700, hhc314 wrote:

It isn't easy to do, since the PCI technology is totally different from
the comparatively simple ISA bus.

Your best bet will be to locate an adapter card, or a motherboard
having both PCI and ISA slots.

Actually, it's not hard to do at all, unless the ISA card is a bus master
(_very_ few were).

How can an ISA card be a *bus master* ?

The device asserts a DRQ, waits for the corresponding DACK, then
asserts MASTER, at which point it can drive the address/data/control
lines as needed.

ISA is just the micro's data and address bus basically with a few extra pins
to the interrupt controller !

It's a *little* more than that.

I think only EISA and MCA cards had that ability prior to the adoption of
PCI.

No, it was there in ISA too, though not often used.

Then goes and wonders over some of the earlyish Adaptec SCSI controllers e.g
AHA1540/1542. In which case how did they do it ?

Yep. There was also the IBM Multi-media Modem (sound card/modem
combined on one DSP) that used bus mastering to swap its OS and data in
and out of system memory.

Thanks for the filling me in on the missing bits. I'll have to revisit the ISA bus
standard to get to grips with this.

Graham

 

[Baugh]

Sam Goldwasser wrote:

Baugh <baconbaugh@charter.net> writes:


Sam Goldwasser wrote:

Dirk Bruere at Neopax <dirk@neopax.com> writes:


rgregoryclark@yahoo.com wrote:



I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?

Quartz lens?

The problem isn't the lens material as much as the beam quality. It
will be
hard to focus the typical home-built N2 laser's output to a very small spot.


Cannot you by placing the lens far enough away from the laser obtain a
better focus? The distance will correlate off-line output with lateral
displacement. A lens of sufficient quality and wide enough for the
spread beam will then redirect more accurately to the focus.

Think of it in terms of the focused image for the distance to the laser
will move closer to the focus from infinity as you move the lens farther
away. (Again assuming no spherical aberation in the lens.)


You're not imaging the output aperture of the laser, you're trying to focus
the beam from the laser. As such, how far away you are isn't very relevant.

However, if you're implying that a large f-number lens is better. Sure.

No I was thinking for a fixed focal length but farther from the source.
As long as the diameter of the lens catches the width of the spreading
beam. Seems to me you could acheive focus up to the order of the
wavelength this way... assuming you could build perfect lenses of a
given focal length to arbitrary diameter.

I'm not sure I'd go so far as to say they aren't coherent asn other posts
have stated, but there is a most one bounc from a rear mirror (which isn't
essential) and the light makes at most two passes through the laser. This
doesn't set up a nice mode structure. As everyone's stated, it is messy.

Right you would get a random mix of coherent "packets", each the
amplification of a single spontaneously emitted photon.

 

[Phil Hobbs]

Harveyx wrote:

See rough sum in the other post.
Basically I agree, but it is just about 'do-able'

Harvey

Of course, if this is the Scientific American laser, it's a monster,
producing millijoule pulses a nanosecond wide, which will cause nice air
plasmas near focus. Focusing tighter than the air breakdown limit will
be a challenge even with good lenses.

The plasma will move rapidly towards the lens, to the point of drilling
holes in it if it's too nearby (I used to have a 40x microscope lens
with a nice 1-mm hole drilled in the front element from this effect).

Cheers,

Phil Hobbs

 

[Sam Goldwasser]

rgregoryclark@yahoo.com writes:

Harveyx wrote:
...
Uncle Al overstates his case a bit.
Why dont we try numbers instead of words..............
Forget 'mode structure' for most N2 lasers, there is essentially
none, they
are single pass. But neither is it *quite* 'a flasbulb'.
To a pretty good approximation crude nitrogen lasers have a
divergence
which is about d/L where d is the 'tube' (discharge, often
transverse)
diameter & L the length.
If you focus it with focal length F your spot diameter is just F*d/L

So, if you want 0.1mm, d is maybe 5mm & L maybe 200mm you would need
a 4mm
focal length, which is operating at F~0,8
You might get a UV transparent microscope objective (at a price) that
gets
near that, but its pretty challenging to put it mildly.

With a longer, thinner laser, and relax it to 'a few' hundred um
spot, and
you would get into just about achievable regimes.
With longer focal lengths, the F number falls, & aberrations are
rapidly
less of an issue - its rather far from diffraction limited!
Lens UV transparency at 337nm is an issue, especially for a thick
short
focus lens.

Harvey

For these homemade nitrogen lasers the tube is just filled with air
and made of transparent plastic, so is quite cheap. Then you could have
a tube length say the full length of your basement, say 10 meters,
10,000mm.

And you're going to excite this laser how?

Then for a diameter of 25mm, you would only need a focal length of
40mm to get a spot diameter of 0.1mm. How are 40mm focal length, 25mm
diameter UV lenses pricewise?

4 mm f/l lenses are quite common. That's not the problem.a

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

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traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
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[Sam Goldwasser]

rgregoryclark@yahoo.com writes:

Sam Goldwasser wrote:
...

For these homemade nitrogen lasers the tube is just filled with
air
and made of transparent plastic, so is quite cheap. Then you could
have
a tube length say the full length of your basement, say 10 meters,
10,000mm.

And you're going to excite this laser how?

Then for a diameter of 25mm, you would only need a focal length of
40mm to get a spot diameter of 0.1mm. How are 40mm focal length,
25mm
diameter UV lenses pricewise?

4 mm f/l lenses are quite common. That's not the problem.a

...

How does input energy scale with the size of laser tube?

I would expect it to be linear. However, it's not only the energy, but
the timing - getting the excitation pulse to be in sync with the light
pulse is not trivial over any distance.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[Harveyx]

<rgregoryclark@yahoo.com> wrote in message
news:1115978664.500553.297350@z14g2000cwz.googlegroups.com...

Harveyx wrote:
...
Uncle Al overstates his case a bit.
Why dont we try numbers instead of words..............
Forget 'mode structure' for most N2 lasers, there is essentially
none, they
are single pass. But neither is it *quite* 'a flasbulb'.
To a pretty good approximation crude nitrogen lasers have a
divergence
which is about d/L where d is the 'tube' (discharge, often
transverse)
diameter & L the length.
If you focus it with focal length F your spot diameter is just F*d/L

So, if you want 0.1mm, d is maybe 5mm & L maybe 200mm you would need
a 4mm
focal length, which is operating at F~0,8
You might get a UV transparent microscope objective (at a price) that
gets
near that, but its pretty challenging to put it mildly.

With a longer, thinner laser, and relax it to 'a few' hundred um
spot, and
you would get into just about achievable regimes.
With longer focal lengths, the F number falls, & aberrations are
rapidly
less of an issue - its rather far from diffraction limited!
Lens UV transparency at 337nm is an issue, especially for a thick
short
focus lens.

Harvey

For these homemade nitrogen lasers the tube is just filled with air
and made of transparent plastic, so is quite cheap. Then you could have
a tube length say the full length of your basement, say 10 meters,
10,000mm.

They 'could'; but given the very rapid discharge needed, it will have to be
transverse excited, & either a rather complicated delay system & one spark
gap, or lots of spark gaps...........

Realistically, a metre is a pain, & anything more pretty impractical.
250-500mm is far more the norm.

Harvey

Then for a diameter of 25mm,

Do any N2 lasers have that big a gap? Maybe, but Ive not seen one.

you would only need a focal length of

40mm to get a spot diameter of 0.1mm. How are 40mm focal length, 25mm
diameter UV lenses pricewise?



Bob Clark

 

[Sam Goldwasser]

"Harveyx" <removeh.rutt@ecs.soton.ac.uk> writes:

rgregoryclark@yahoo.com> wrote in message
news:1115978664.500553.297350@z14g2000cwz.googlegroups.com...
Harveyx wrote:
...
Uncle Al overstates his case a bit.
Why dont we try numbers instead of words..............
Forget 'mode structure' for most N2 lasers, there is essentially
none, they
are single pass. But neither is it *quite* 'a flasbulb'.
To a pretty good approximation crude nitrogen lasers have a
divergence
which is about d/L where d is the 'tube' (discharge, often
transverse)
diameter & L the length.
If you focus it with focal length F your spot diameter is just F*d/L

So, if you want 0.1mm, d is maybe 5mm & L maybe 200mm you would need
a 4mm
focal length, which is operating at F~0,8
You might get a UV transparent microscope objective (at a price) that
gets
near that, but its pretty challenging to put it mildly.

With a longer, thinner laser, and relax it to 'a few' hundred um
spot, and
you would get into just about achievable regimes.
With longer focal lengths, the F number falls, & aberrations are
rapidly
less of an issue - its rather far from diffraction limited!
Lens UV transparency at 337nm is an issue, especially for a thick
short
focus lens.

Harvey

For these homemade nitrogen lasers the tube is just filled with air
and made of transparent plastic, so is quite cheap. Then you could have
a tube length say the full length of your basement, say 10 meters,
10,000mm.

They 'could'; but given the very rapid discharge needed, it will have to be
transverse excited, & either a rather complicated delay system & one spark
gap, or lots of spark gaps...........

Realistically, a metre is a pain, & anything more pretty impractical.
250-500mm is far more the norm.

Harvey

Then for a diameter of 25mm,

Do any N2 lasers have that big a gap? Maybe, but Ive not seen one.

I think what he means is that once the beam spreads to 25 mm.....

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

you would only need a focal length of
40mm to get a spot diameter of 0.1mm. How are 40mm focal length, 25mm
diameter UV lenses pricewise?



Bob Clark

 

[nightbat]

nightbat wrote

rgregoryclark@yahoo.com wrote:

Sam Goldwasser wrote:
rgregoryclark@yahoo.com writes:

Sam Goldwasser wrote:
...

For these homemade nitrogen lasers the tube is just filled
with
air
and made of transparent plastic, so is quite cheap. Then you
could
have
a tube length say the full length of your basement, say 10
meters,
10,000mm.

And you're going to excite this laser how?

Then for a diameter of 25mm, you would only need a focal
length of
40mm to get a spot diameter of 0.1mm. How are 40mm focal
length,
25mm
diameter UV lenses pricewise?

4 mm f/l lenses are quite common. That's not the problem.a

...

How does input energy scale with the size of laser tube?

I would expect it to be linear. However, it's not only the energy,
but
the timing - getting the excitation pulse to be in sync with the
light
pulse is not trivial over any distance.

...

OK, the problems with just using air at standard pressure may be
insurmountable for my application.

However, this page suggests homebuilt nitrogen lasers can be used for
micromachining with the lasing gas at low pressure:

The Nitrogen Gas Laser.
"This laser produces intense, short, pulses of UV radiation at 337.1nm
and is useful for applications ranging from microcutting to pumping dye
lasers. This is one of the easiest gas lasers to build 'from scratch'
although the electrical discharge circuitry must be carefully
designed."
http://www.technology.niagarac.on.ca/people/mcsele/lasers/LasersN2.htm

The page suggests a vacuum pump to get the nitrogen down to 25 torr,
about 3% of standard pressure, is simple and low cost.
This company has prices for low cost UV lenses:

UV Optics - PCX.
http://www.hiteckint.com/product/optics/leans-pcxuv.htm

They give a price for a 6mm diameter, 9 mm focal length UV lens as
about $5.00. This is a Hong Kong company however.

Bob Clark

nightbat

Thanks for the relative posted subject info Bob, reference
links, and all additional info from contributing posters. Could be
useful for possible low cost contruction of initial Star Race D.R.I.L.L.

the nightbat

 

[John Miller]

Dave wrote:

How can I create a 8Hz Sine Wave 220 volts signal. If
I convert the AC 220 volts to DC. Will I still get 220
volts? So what's the smallest circuit or device that
can make 8Hz sine wave out of the 220 volts DC. Thanks.

At how many amps?

--
John Miller
email domain: n4vu.com; username: jsm(@)
Surplus (For sale or trade):
Besson International Trumpet by Kanstul

 

[Matthias Melcher]

A light bulb flickering at 20Hz would drive you nuts within 2 minutes.

50Hz is a frequency that is perceived by most humans as a steady light, 60Hz
is better. The frequency is generated by - um - the generators that run at
your local power plant. They are kept strictly in sync over the day (in the
so called "modern" world), because many clocks depend on the correct
frequency to keep time.

"Dave" <davidqanta@yahoo.com> schrieb im Newsbeitrag
news:1116073837.278651.315220@g43g2000cwa.googlegroups.com...

Hi,

How is AC 60 Hz and not 30 Hz. What is so significant about 60
or 50Hz? Can't bulb or electric motors run at 20 Hz or so??

Dave

 

[Joe Soap]

In response to what Matthias Melcher <no-spame-matt@matthiasm.com> posted
in news:d652ig$t11$05$1@news.t-online.com:

50Hz is a frequency that is perceived by most humans as a steady light

but only because the flicker frequency is actually 100Hz - the lamp
brightens and dims twice per cycle.

--
Joe Soap.
JUNK is stuff that you keep for 20 years,
then throw away a week before you need it.

 

[Dwayne]

"Dave" <davidqanta@yahoo.com> wrote in message
news:1116073837.278651.315220@g43g2000cwa.googlegroups.com...

Hi,

How is AC 60 Hz and not 30 Hz. What is so significant about 60
or 50Hz? Can't bulb or electric motors run at 20 Hz or so??

Dave

Higher frequencies have higher loss.
You body has more resistance to higher frequencies.
You eyes can perceive light flicker at 40 Hertz.
You nerve system runs at ~40 Hertz.

So low frequency is bad for lighting and electrocution. High frequencies are
bad for motors. Thus the compromise.

Dwayne

 

[RST Engineering (jw)]

That doesn't happen to be true. The so-called flicker rate for the eye is
24 Hz. ANything faster than that is perceived to be steady light. Witness
the standard TV set with a frame rate of 30 Hz. (2 interlaced sets of video
at 60 Hz.). No flicker there that I can see, nor anybody else for that
matter.

Jim

but only because the flicker frequency is actually 100Hz - the lamp
brightens and dims twice per cycle.

 

[Guillaume]

RST Engineering (jw) wrote:

That doesn't happen to be true. The so-called flicker rate for the eye is
24 Hz. ANything faster than that is perceived to be steady light. Witness
the standard TV set with a frame rate of 30 Hz. (2 interlaced sets of video
at 60 Hz.). No flicker there that I can see, nor anybody else for that
matter.

You can't "see" it, but you can perceive it. Low-refresh rate light
sources are known to cause eye strain or even headaches. Anything
below 100 to 200 Hz *will* be perceived by your neurons. You may
not directly be aware of it - but it has some effect. To your brain,
it is some kind of "noise" that has to be sorted out on low levels,
hence the possible headaches and attention span troubles.

As for TV and CRTs in general, your assertion is pretty much off,
because another problem with CRTs is not just the frame rate - but
the fact the image is itself not steady in each frame. So between
a 30 Hz and a 100 Hz frame rate on a CRT, I guarantee you that you
can actually tell the difference.

 

[Joe Soap]

In response to what RST Engineering (jw) <jim@rstengineering.com> posted
in news:118cb8mf6f7ga4c@corp.supernews.com:

That doesn't happen to be true. The so-called flicker rate for the
eye is 24 Hz. ANything faster than that is perceived to be steady
light. Witness the standard TV set with a frame rate of 30 Hz. (2
interlaced sets of video at 60 Hz.). No flicker there that I can see,
nor anybody else for that matter.

Jim


but only because the flicker frequency is actually 100Hz - the lamp
brightens and dims twice per cycle.

So try feeding a lamp via a diode, and report back on the flicker.

--
Joe Soap.
JUNK is stuff that you keep for 20 years,
then throw away a week before you need it.

 

[Vidar Lřkken]

Joe Soap wrote:

but only because the flicker frequency is actually 100Hz - the lamp
brightens and dims twice per cycle.


So try feeding a lamp via a diode, and report back on the flicker.

The other thing to take in is that it won't dim before the filament has
cooled enough to output a different colored light. So higher frequency
also means it has less time to cool down...

--
MVH,
Vidar

www.bitsex.net