"white" LED and osc. current source question

[Michael]

John Woodgate wrote:

I read in sci.electronics.design that Mark Jones <abuse@127.0.0.1> wrote
(in <2fOdnT3zZrPZPajfRVn-oQ@buckeye-express.com&gt about '"white" LED and
osc. current source question', on Mon, 14 Mar 2005:
Maybe get into making a coilgun rifle?

Running from a 1.5 V cell?
--

And with a super-bright Power-On LED.

 

[Michael]

Not to be left in the dust with all the white LED single AA cell experimenting
going on here, I decide to have a go. Scavenged wire from the coil of an old
speaker and wound some of it on the only toroid I could lay hands on, 0.75".
Not having a proper xstr, I used the venerable 2N3904. Got oscillation right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only 50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more blue
than white.

 

[John Popelish]

Michael wrote:

Not to be left in the dust with all the white LED single AA cell experimenting
going on here, I decide to have a go. Scavenged wire from the coil of an old
speaker and wound some of it on the only toroid I could lay hands on, 0.75".
Not having a proper xstr, I used the venerable 2N3904. Got oscillation right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only 50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more blue
than white.

Radio Shack may have a little assortment of magnet wire, each size
wound on the little white spools that wire wrap wire comes on.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=278-1345
Come to think of it, a spool of 30 ga. silver plated wire wrap wire
works well for this kind of experiment and the insulation is a lot
tougher than enamel. Radio Shack used to carry those, also.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=278-503

--
John Popelish

 

[Michael]

John Popelish wrote:

Michael wrote:

Not to be left in the dust with all the white LED single AA cell experimenting
going on here, I decide to have a go. Scavenged wire from the coil of an old
speaker and wound some of it on the only toroid I could lay hands on, 0.75".
Not having a proper xstr, I used the venerable 2N3904. Got oscillation right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only 50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more blue
than white.

Radio Shack may have a little assortment of magnet wire, each size
wound on the little white spools that wire wrap wire comes on.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=278-1345
Come to think of it, a spool of 30 ga. silver plated wire wrap wire
works well for this kind of experiment and the insulation is a lot
tougher than enamel. Radio Shack used to carry those, also.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=278-503

--
John Popelish

Don't want to search for - much less buy - the perfect wire. I'm just puttering
around here. Toroid and wire are "found stuff". Would like to use the 20#
enameled, if the piece I have is long enough to give the needed inductance when
wound on the .75" toroid.

Silver plated wire wrap wire ... interesting. I must have wrapped miles of wire
in my technician days but never knew any of it was silver plated. Apparently
some was, because several years ago, while canibalizing a digital clock I built
back in 1973, I found all the wraps were black as coal!

 

[Bob]

"Michael" <NoSpam@att.net> wrote in message
news:4234CCE7.8E912BC2@att.net...

Not to be left in the dust with all the white LED single AA cell
experimenting
going on here, I decide to have a go. Scavenged wire from the coil of an
old
speaker and wound some of it on the only toroid I could lay hands on,
0.75".
Not having a proper xstr, I used the venerable 2N3904. Got oscillation
right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only
50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more
blue
than white.

I recently needed some 34awg magnet wire. I only needed a few feet of the
stuff, but the place I got it from had a 10lb minimum. Let me tell you ---
that's a LOT of 34awg wire!

Maybe I'll open a 34awg magnet wire store.

Bob

 

[Mark Jones]

Bob wrote:

"Michael" <NoSpam@att.net> wrote in message
news:4234CCE7.8E912BC2@att.net...

Not to be left in the dust with all the white LED single AA cell

experimenting

going on here, I decide to have a go. Scavenged wire from the coil of an

old

speaker and wound some of it on the only toroid I could lay hands on,

0.75".

Not having a proper xstr, I used the venerable 2N3904. Got oscillation

right

away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only

50-60"

of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more

blue

than white.


I recently needed some 34awg magnet wire. I only needed a few feet of the
stuff, but the place I got it from had a 10lb minimum. Let me tell you ---
that's a LOT of 34awg wire!

Maybe I'll open a 34awg magnet wire store.

Bob

Maybe get into making a coilgun rifle?

 

[John Woodgate]

I read in sci.electronics.design that Mark Jones <abuse@127.0.0.1> wrote
(in <2fOdnT3zZrPZPajfRVn-oQ@buckeye-express.com&gt about '"white" LED and
osc. current source question', on Mon, 14 Mar 2005:

Maybe get into making a coilgun rifle?

Running from a 1.5 V cell?
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Mark Jones]

John Woodgate wrote:

I read in sci.electronics.design that Mark Jones <abuse@127.0.0.1> wrote
(in <2fOdnT3zZrPZPajfRVn-oQ@buckeye-express.com&gt about '"white" LED and
osc. current source question', on Mon, 14 Mar 2005:

Maybe get into making a coilgun rifle?


Running from a 1.5 V cell?

Now that would be a design challenge!

 

[Michael]

Bob wrote:

"Michael" <NoSpam@att.net> wrote in message
news:4234CCE7.8E912BC2@att.net...
Not to be left in the dust with all the white LED single AA cell
experimenting
going on here, I decide to have a go. Scavenged wire from the coil of an
old
speaker and wound some of it on the only toroid I could lay hands on,
0.75".
Not having a proper xstr, I used the venerable 2N3904. Got oscillation
right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only
50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more
blue
than white.

I recently needed some 34awg magnet wire. I only needed a few feet of the
stuff, but the place I got it from had a 10lb minimum. Let me tell you ---
that's a LOT of 34awg wire!

Maybe I'll open a 34awg magnet wire store.

Bob

I faced a wire acquisition dilemma back in my college days. I had built a bench
variable DC supply and needed several yards of heavy enameled wire to carefully
wind (non-inductively, knock-on-wood) and put in series with the supply output,
for current sensing. A prof. suggested a particular motor shop close to campus,
so I went and asked how much they'd charge for some (wire size) wire. "How much
do you need?" I thought, oh nuts! the guy expects me to buy miles of the
stuff. When I told him I wanted only 10-15 feet he snorted, walked over to a
spool and whipped off yards and yards for me. Even coiled and taped it for me.
And he didn't charge a cent. I walked back to my apartment on a cloud.

 

[Michael]

Michael wrote:

Not to be left in the dust with all the white LED single AA cell experimenting
going on here, I decide to have a go. Scavenged wire from the coil of an old
speaker and wound some of it on the only toroid I could lay hands on, 0.75".
Not having a proper xstr, I used the venerable 2N3904. Got oscillation right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only 50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more blue
than white.

I ripped the hair wire off my toroid and re-wound it with 21 turns of the 20#
stuff. It works but of course it's impossible to compare operation of the two
circuits now. I'm gonna take another look through mountains of "junk" and mebbe
find a SWPS with a small toroid that I can rip out.

And I'm definitely gonna buy a Zetex low Vce xstr to play with. But first I'll
check with photo shops in the area and ask for disposable cameras!

 

Michael wrote:

Not to be left in the dust with all the white LED single AA cell
experimenting
going on here, I decide to have a go. Scavenged wire from the coil
of an old
speaker and wound some of it on the only toroid I could lay hands
on, 0.75".
Not having a proper xstr, I used the venerable 2N3904. Got
oscillation right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I
used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but
only 50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are
more blue
than white.

Michael wrote:
I ripped the hair wire off my toroid and re-wound it with 21 turns of
the
20# stuff. It works but of course it's impossible to compare
operation
of the two circuits now. I'm gonna take another look through
mountains of "junk" and mebbe find a SWPS with a small toroid that
I can rip out.

And I'm definitely gonna buy a Zetex low Vce xstr to play
with. But first I'll check with photo shops in the area and
ask for disposable cameras!

Those Zetex trannies *are* lovely, but meanwhile you can get
a large improvement just using a heftier jellybean. The 2n2222a's
Vce(sat) is much better than that 2n3904 you're using. MPSA06
and 2n4401 are others to consider.

As for disposable camera strobe, those transistors saturate, but gain
is often (or at least was, a few years back) horrible.

James Arthur

 

[Terry Given]

Michael wrote:

John Popelish wrote:

Michael wrote:

Not to be left in the dust with all the white LED single AA cell experimenting
going on here, I decide to have a go. Scavenged wire from the coil of an old
speaker and wound some of it on the only toroid I could lay hands on, 0.75".
Not having a proper xstr, I used the venerable 2N3904. Got oscillation right
away, much to my amazement.

But the thing needs a proper transistor. Also, the magnet wire I used is
*tiny*. More like hair than wire. I have some 20# magnet wire, but only 50-60"
of it I'd guess. Does that sound like enough?

I gotta get some proper white LEDs. The several cheapos I have are more blue
than white.

Radio Shack may have a little assortment of magnet wire, each size
wound on the little white spools that wire wrap wire comes on.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=278-1345
Come to think of it, a spool of 30 ga. silver plated wire wrap wire
works well for this kind of experiment and the insulation is a lot
tougher than enamel. Radio Shack used to carry those, also.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=278-503

--
John Popelish



Don't want to search for - much less buy - the perfect wire. I'm just puttering
around here. Toroid and wire are "found stuff". Would like to use the 20#
enameled, if the piece I have is long enough to give the needed inductance when
wound on the .75" toroid.

Silver plated wire wrap wire ... interesting. I must have wrapped miles of wire
in my technician days but never knew any of it was silver plated. Apparently
some was, because several years ago, while canibalizing a digital clock I built
back in 1973, I found all the wraps were black as coal!

that doesn't necessarily mean it was silver though. I used to live in
Rotorua NZ, a geothermal hot-spot. It plays absolute hell with
electronics in general, and crimped connections in particular. Back when
I was a videogame tech I used to have to re-wire entire cabinets after 2
years or so - the coloured PVC insulation all went a murky brown colour
(just like the inside of PAs mouth) and the crimps corroded to hell. We
had to scrape back the insulation just to tell what colour the damned
wire was. We also soldered every crimped connection, to make it last
longer. un-tinned Cu wire would disappear very rapidly.

Later on in life I helped service some AC motor controllers that had
been in a fertiliser factory, and they were just as bad; most of the
pcbs were written off - tracks gone completely etc. Here's another nasty
gotcha with crimps - when using PVC insulation, if you heat it to about
70C it outgasses chlorine, which eats away at the crimp, making it get
hotter and outgas more.....voila, positive feedback. It was a *huge*
issue in a 400A motor controller (at least it was back when they were
built with cables and crimped connections). Yay for X-linked polymer
sheathed cables like Radox.


Cheers
Terry