http://members.goldengate.net/dforeman/yellowlight/

NEAT !!!!



On Wed, 06 Jan 2010 22:22:56 -0600, Don Foreman
wrote:

http://members.goldengate.net/dforeman/yellowlight/

Don Foreman wrote:
http://members.goldengate.net/dforeman/yellowlight/

Extremely cool, Don.

--Winston

--

Congratulations Robert Piccinini and Steven A. Burd, WalMart Publicists of the Year!

On Jan 6, 11:22*pm, Don Foreman wrote:
http://members.goldengate.net/dforeman/yellowlight/

Schweet.


Dave

On Wed, 06 Jan 2010 22:22:56 -0600, Don Foreman
wrote:

http://members.goldengate.net/dforeman/yellowlight/

Velly nice!

What do you use for a power supply?

On Jan 6, 8:22*pm, Don Foreman wrote:
http://members.goldengate.net/dforeman/yellowlight/

Nicely done!

Paul

On Thu, 07 Jan 2010 10:28:57 -0500, Spehro Pefhany
wrote:

On Wed, 06 Jan 2010 22:22:56 -0600, Don Foreman
wrote:

http://members.goldengate.net/dforeman/yellowlight/

Velly nice!

What do you use for a power supply?

That's my next project. G It needs to be a 700 mA current source
with load voltage circa 3 volts or so. Previous version was 350 mA so
an LM317 and sense resistor epoxied on the top of a wallwart sufficed.
Might work here too if I can find a 4.5 or 6 volt 700mA wallwart.
Else, maybe a little switcher.

Good job - as per the usual Foreman standard.

Bob Swinney
"Don Foreman" wrote in message
...
http://members.goldengate.net/dforeman/yellowlight/

On Thu, 07 Jan 2010 12:30:23 -0600, Don Foreman
wrote:

On Thu, 07 Jan 2010 10:28:57 -0500, Spehro Pefhany
wrote:

On Wed, 06 Jan 2010 22:22:56 -0600, Don Foreman
wrote:

http://members.goldengate.net/dforeman/yellowlight/

Velly nice!

What do you use for a power supply?

That's my next project. G It needs to be a 700 mA current source
with load voltage circa 3 volts or so. Previous version was 350 mA so
an LM317 and sense resistor epoxied on the top of a wallwart sufficed.
Might work here too if I can find a 4.5 or 6 volt 700mA wallwart.
Else, maybe a little switcher.

It's cheating a bit, but have you seen these?

http://www.leddynamics.com/LuxDrive/...1-BuckPlus.pdf

$15.99 in one-off for the 700mA version and another $1 for the one
with dimming.

On Jan 6, 10:22*pm, Don Foreman wrote:
http://members.goldengate.net/dforeman/yellowlight/

Looks like it might be a useful idea for making a small camera mount
too.

Don Foreman wrote:

http://members.goldengate.net/dforeman/yellowlight/


Nice work Don.

Wes

On Thu, 07 Jan 2010 12:30:23 -0600, the infamous Don Foreman
scrawled the following:

On Thu, 07 Jan 2010 10:28:57 -0500, Spehro Pefhany
wrote:

On Wed, 06 Jan 2010 22:22:56 -0600, Don Foreman
wrote:

http://members.goldengate.net/dforeman/yellowlight/

Velly nice!

I'll echo that one, too.


What do you use for a power supply?

That's my next project. G It needs to be a 700 mA current source
with load voltage circa 3 volts or so. Previous version was 350 mA so
an LM317 and sense resistor epoxied on the top of a wallwart sufficed.
Might work here too if I can find a 4.5 or 6 volt 700mA wallwart.
Else, maybe a little switcher.

Remember to spray paint this one poorly. It'll take the shine off it
so it doesn't disappear like the last one. You know how thieves are
when it comes to shiny baubles.

--
We rightly care about the environment. But our neurotic obsession
with carbon betrays an inability to distinguish between pollution
and the stuff of life itself. --Bret Stephens, WSJ 1/5/10

Don Foreman wrote:
http://members.goldengate.net/dforeman/yellowlight/


Very neat little job .

Found this one on alink on Utubeto site regarding a magazine called Make.

http://www.flickr.com/photos/lishnes.../in/pool-make/
--
Kevin (Bluey)
"I'm not young enough to know everything."

On Thu, 07 Jan 2010 14:35:21 -0500, Spehro Pefhany
wrote:

On Thu, 07 Jan 2010 12:30:23 -0600, Don Foreman
wrote:

On Thu, 07 Jan 2010 10:28:57 -0500, Spehro Pefhany
wrote:

On Wed, 06 Jan 2010 22:22:56 -0600, Don Foreman
wrote:

http://members.goldengate.net/dforeman/yellowlight/

Velly nice!

What do you use for a power supply?

That's my next project. G It needs to be a 700 mA current source
with load voltage circa 3 volts or so. Previous version was 350 mA so
an LM317 and sense resistor epoxied on the top of a wallwart sufficed.
Might work here too if I can find a 4.5 or 6 volt 700mA wallwart.
Else, maybe a little switcher.

It's cheating a bit, but have you seen these?

http://www.leddynamics.com/LuxDrive/...1-BuckPlus.pdf

$15.99 in one-off for the 700mA version and another $1 for the one
with dimming.

After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.

I need to go to a switcher because of my available xfmr choices. I
have several that have the necessary 2.4VA ratings but they're all
rated for more voltage and less current than I need. A switcher
solves that nicely.

Current ripple will probably be about 200 mA P-P, which doesn't matter
at all in this app. The biggest inefficiency is in the current sense
resistor where maybe a quarter watt becomes heat, oh dear! Uh no, by
far the dominant inefficiency and heat generator will be the xfmr.

On Fri, 08 Jan 2010 23:45:09 -0600, the renowned Don Foreman
wrote:

On Thu, 07 Jan 2010 14:35:21 -0500, Spehro Pefhany
wrote:

On Thu, 07 Jan 2010 12:30:23 -0600, Don Foreman
wrote:

On Thu, 07 Jan 2010 10:28:57 -0500, Spehro Pefhany
wrote:

On Wed, 06 Jan 2010 22:22:56 -0600, Don Foreman
wrote:

http://members.goldengate.net/dforeman/yellowlight/

Velly nice!

What do you use for a power supply?

That's my next project. G It needs to be a 700 mA current source
with load voltage circa 3 volts or so. Previous version was 350 mA so
an LM317 and sense resistor epoxied on the top of a wallwart sufficed.
Might work here too if I can find a 4.5 or 6 volt 700mA wallwart.
Else, maybe a little switcher.

It's cheating a bit, but have you seen these?

http://www.leddynamics.com/LuxDrive/...1-BuckPlus.pdf

$15.99 in one-off for the 700mA version and another $1 for the one
with dimming.

After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.

I need to go to a switcher because of my available xfmr choices. I
have several that have the necessary 2.4VA ratings but they're all
rated for more voltage and less current than I need. A switcher
solves that nicely.

Current ripple will probably be about 200 mA P-P, which doesn't matter
at all in this app. The biggest inefficiency is in the current sense
resistor where maybe a quarter watt becomes heat, oh dear! Uh no, by
far the dominant inefficiency and heat generator will be the xfmr.


That should work nicely. The ripple will give you more heating than
otherwise, of course. Usual LED mfr recommendations are 5-20% maximum
current ripple.

Here's another "canned" solution:
http://www.sure-electronics.net/DC,I...s/LE-LL209.pdf

At the other end of the scale, do you have any of those 5V switchers
laying around? Last I looked, a surplus place near me has a big stack
of brand new compact 5V wall plug switchers for about $2-3. Inside is
a flyback converter using a UC3843 (clone), with the usual TL431 2.5V
reference/optoisolator feedback, so changing the resistor ratio on the
TL431 would allow the voltage to be lowered to something like 3.5V. (I
gently crack the ultrasonic case welding open with a vise, then they
can be glued shut again with epoxy- usually you can't tell they were
ever opened without looking very closely.).


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Sat, 09 Jan 2010 10:04:25 -0500, Spehro Pefhany
wrote:

On Fri, 08 Jan 2010 23:45:09 -0600, the renowned Don Foreman
wrote:

SNIP SNIP SNIP

After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.

I need to go to a switcher because of my available xfmr choices. I
have several that have the necessary 2.4VA ratings but they're all
rated for more voltage and less current than I need. A switcher
solves that nicely.

Current ripple will probably be about 200 mA P-P, which doesn't matter
at all in this app. The biggest inefficiency is in the current sense
resistor where maybe a quarter watt becomes heat, oh dear! Uh no, by
far the dominant inefficiency and heat generator will be the xfmr.


That should work nicely. The ripple will give you more heating than
otherwise, of course. Usual LED mfr recommendations are 5-20% maximum
current ripple.

Here's another "canned" solution:
http://www.sure-electronics.net/DC,I...s/LE-LL209.pdf

At the other end of the scale, do you have any of those 5V switchers
laying around? Last I looked, a surplus place near me has a big stack
of brand new compact 5V wall plug switchers for about $2-3. Inside is
a flyback converter using a UC3843 (clone), with the usual TL431 2.5V
reference/optoisolator feedback, so changing the resistor ratio on the
TL431 would allow the voltage to be lowered to something like 3.5V. (I
gently crack the ultrasonic case welding open with a vise, then they
can be glued shut again with epoxy- usually you can't tell they were
ever opened without looking very closely.).


Best regards,
Spehro Pefhany

Hey you two,

I know there's lots of OT stuff here on RCM, but it's ALMOST ALWAYS in
ENGLISH !!!
So how about sticking with the common language in this thread!?!?!?

Heh heh heh.

Brian Lawson,
Bothwell, Ontario.

ps....actually, I enjoyed going through my catalogues trying to figure
out what you were doing!!

On Jan 9, 3:03*pm, Brian Lawson wrote:
On Sat, 09 Jan 2010 10:04:25 -0500, Spehro Pefhany
On Fri, 08 Jan 2010 23:45:09 -0600, the renowned Don Foreman

... hysteretic switching *current regulator ...220 uH inductor
...MCP6022 opamp, *MOSFET, Schottky diode, sense
resistor and voltage reference.

... a flyback converter using a UC3843 (clone), with the usual TL431 2..5V
reference/optoisolator feedback, so changing the resistor ratio on the
TL431 would allow the voltage to be lowered to something like 3.5V. ...
Spehro Pefhany

Hey you two,

I know there's lots of OT stuff here on RCM, but it's ALMOST ALWAYS in
ENGLISH !!! *
So how about sticking with the common language in this thread!?!?!?

Heh heh heh.

Brian Lawson,
Bothwell, Ontario.

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.

jsw

On Sat, 09 Jan 2010 15:03:33 -0500, Brian Lawson
wrote:

On Sat, 09 Jan 2010 10:04:25 -0500, Spehro Pefhany
wrote:

On Fri, 08 Jan 2010 23:45:09 -0600, the renowned Don Foreman
wrote:

SNIP SNIP SNIP

After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.

I need to go to a switcher because of my available xfmr choices. I
have several that have the necessary 2.4VA ratings but they're all
rated for more voltage and less current than I need. A switcher
solves that nicely.

Current ripple will probably be about 200 mA P-P, which doesn't matter
at all in this app. The biggest inefficiency is in the current sense
resistor where maybe a quarter watt becomes heat, oh dear! Uh no, by
far the dominant inefficiency and heat generator will be the xfmr.


That should work nicely. The ripple will give you more heating than
otherwise, of course. Usual LED mfr recommendations are 5-20% maximum
current ripple.

Here's another "canned" solution:
http://www.sure-electronics.net/DC,I...s/LE-LL209.pdf

At the other end of the scale, do you have any of those 5V switchers
laying around? Last I looked, a surplus place near me has a big stack
of brand new compact 5V wall plug switchers for about $2-3. Inside is
a flyback converter using a UC3843 (clone), with the usual TL431 2.5V
reference/optoisolator feedback, so changing the resistor ratio on the
TL431 would allow the voltage to be lowered to something like 3.5V. (I
gently crack the ultrasonic case welding open with a vise, then they
can be glued shut again with epoxy- usually you can't tell they were
ever opened without looking very closely.).


Best regards,
Spehro Pefhany

Hey you two,

I know there's lots of OT stuff here on RCM, but it's ALMOST ALWAYS in
ENGLISH !!!
So how about sticking with the common language in this thread!?!?!?

Heh heh heh.

Brian Lawson,
Bothwell, Ontario.

Well, ya connect the libtard to the neocon via the winger ...
nevermind.

On Fri, 08 Jan 2010 23:45:09 -0600, Don Foreman
wrote:


After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.


Where did all those nice unijunction transistors of yesteryear go :-(


Mark Rand
RTFM

Jim Wilkins wrote:

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.


It's more fun when you toss in the other MEs (Manufacturing
Engineering) to the mix. Each group thinks they are the only ones who
matter.



--
Greed is the root of all eBay.

Jim Wilkins wrote:

(...)

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.

A sales guy I knew, frustrated with the noises made by electronic
engineers dubbed their language "di double - E feedback".

--Winston

Mark Rand wrote:
On Fri, 08 Jan 2010 23:45:09 -0600, Don Foreman
wrote:

After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.


Where did all those nice unijunction transistors of yesteryear go :-(

Check two bins to the right of the Tunnel Diodes.

--Winston


--

Congratulations Robert Piccinini and Steven A. Burd, WalMart Publicists of the Year!

On Jan 9, 8:46*pm, "Michael A. Terrell"
wrote:
Jim Wilkins wrote:

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.

* *It's more fun when you toss in the other MEs (Manufacturing
Engineering) to the mix. Each group thinks they are the only ones who
matter.

I've only worked directly for one Manufacturing Engineer and he was
happy to let me design circuits and otherwise do as I pleased.

But yes, they can all become very defensive and territorial. Sometimes
after the hardware is functional I work for the software group as a
test engineer. Another can of worms opened.

jsw

"Mark Rand" wrote in message
...
On Fri, 08 Jan 2010 23:45:09 -0600, Don Foreman
wrote:


After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.


Where did all those nice unijunction transistors of yesteryear go :-(


Mark Rand
RTFM

Probably a few up in the attic.

On Sun, 10 Jan 2010 00:48:00 +0000, Mark Rand
wrote:

On Fri, 08 Jan 2010 23:45:09 -0600, Don Foreman
wrote:


After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.


Where did all those nice unijunction transistors of yesteryear go :-(


Mark Rand
RTFM

They're still available. 48 cents at Digi-Key
http://tinyurl.com/y86xeer

In the UK, Farnell's has 'em:
http://tinyurl.com/y9gk9fx

On Sat, 09 Jan 2010 18:33:30 -0800, Winston
wrote:

Jim Wilkins wrote:

(...)

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.

A sales guy I knew, frustrated with the noises made by electronic
engineers dubbed their language "di double - E feedback".

--Winston

Whereas, a sales guy or politician can speak for 20 minutes without
saying a damned thing so it doesn't matter whether or not their
utterance is comprehensible.

On Sat, 09 Jan 2010 10:04:25 -0500, Spehro Pefhany
wrote:



At the other end of the scale, do you have any of those 5V switchers
laying around? Last I looked, a surplus place near me has a big stack
of brand new compact 5V wall plug switchers for about $2-3.

The surplus store near me has some but they want more like 12 bux for
them. Arrgghh, highway robbery! I found a little 2.4VA 8VRMS 60-Hz
xfmr in my goodiebox that should work nicely.

On 1/9/2010 11:27 PM, Don Foreman wrote:
I found a little 2.4VA 8VRMS 60-Hz
xfmr in my goodiebox that should work nicely.


I used to use a lot of the LT "simple switcher" eval boards. Cheap (at
the time they were 8 bucks), small (1" X 2") and easy to mod.

Kevin Gallimore

On Sat, 09 Jan 2010 22:16:16 -0600, the renowned Don Foreman
wrote:

On Sun, 10 Jan 2010 00:48:00 +0000, Mark Rand
wrote:

On Fri, 08 Jan 2010 23:45:09 -0600, Don Foreman
wrote:


After thinking about that some today, I'm leaning toward a dirt-simple
hysteretic switching current regulator comprised of a 220 uH inductor
(35 cents at AxMan), MCP6022 opamp, MOSFET, Schottky diode, sense
resistor and voltage reference. Maybe 2 more resistors to get a 0.5
volt ref from a 1.23V bandgap device. All bench stock. I sometimes
build such simple circuits "in air", no circuit board. Just solder
the various parts together with perhaps a bit of hookup wire and then
pot the lot in epoxy on top of the wallwart xfmr that supplies the
low-voltage line-isolated DC.


Where did all those nice unijunction transistors of yesteryear go :-(


Mark Rand
RTFM

They're still available. 48 cents at Digi-Key
http://tinyurl.com/y86xeer

In the UK, Farnell's has 'em:
http://tinyurl.com/y9gk9fx

And they are cheap. But the 2N6027/8 are PUTs, a kind of SCR-like
4-layer thyristor device, not real unijunctions (eg. 2N2646).

But Newark still has the 2N2646 :
http://www.newark.com/jsp/search/pro...FC-GB100000001
http://www.newark.com/multicomp/2n26... iscretes_None

I miss LASCRs (light activated SCRs), SBS (Silicon bilateral
switches), tunnel diodes, germanium transistors, clean air, tuna,
Taiwan.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On 2010-01-10, Spehro Pefhany wrote:

[ ... ]

I miss LASCRs (light activated SCRs), SBS (Silicon bilateral
switches), tunnel diodes, germanium transistors, clean air, tuna,
Taiwan.

How many here have ever heard of a "binistor"? A 4-pin bistable
device which apparently never took off in the market. It was a
four-layer device (like a SCR -- except that it had another pin to allow
turning it off.

IIRC, Transitron gave it the designation 3N21. I could look it
up in the old Transitron data book -- but I don't know where that is at
the moment. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 10 Jan 2010 23:23:50 GMT, "DoN. Nichols"
wrote:

3N21


Hey DoN,

http://www.americanmicrosemi.com/information/spec/?ss_pn=3N21

On 1/10/2010 6:23 PM, DoN. Nichols wrote:

How many here have ever heard of a "binistor"? A 4-pin bistable
device which apparently never took off in the market. It was a
four-layer device (like a SCR -- except that it had another pin to allow
turning it off.

IIRC, Transitron gave it the designation 3N21. I could look it
up in the old Transitron data book -- but I don't know where that is at
the moment. :-)


I knew them as SCSs (silicon controlled switch).

Kevin Gallimore

DoN. Nichols wrote:
On 2010-01-10, Spehro Pefhany wrote:

[ ... ]

I miss LASCRs (light activated SCRs), SBS (Silicon bilateral
switches), tunnel diodes, germanium transistors, clean air, tuna,
Taiwan.

How many here have ever heard of a "binistor"? A 4-pin bistable
device which apparently never took off in the market. It was a
four-layer device (like a SCR -- except that it had another pin to allow
turning it off.

IIRC, Transitron gave it the designation 3N21. I could look it
up in the old Transitron data book -- but I don't know where that is at
the moment. :-)

Enjoy,
DoN.


Sounds like a GTO:
http://en.wikipedia.org/wiki/Gate_turn-off_thyristor
http://www.youtube.com/watch?v=o_FSicQWimU

--Winston

--

You taught me tolerance, kindness, generosity and optimism.

By example, yes?

On 2010-01-10, Brian Lawson wrote:
On 10 Jan 2010 23:23:50 GMT, "DoN. Nichols"
wrote:

3N21


Hey DoN,

http://www.americanmicrosemi.com/information/spec/?ss_pn=3N21

O.K. Germanium means that I have given the wrong part number.
It was a silicon device. I wonder what those 3N devices were, how they
earned the leading 3 instead of 2. Transitron used it as a count of
junctions (e.g. one less than the number of leads.

Thanks,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Sun, 10 Jan 2010 16:17:37 -0800, Winston
wrote:

DoN. Nichols wrote:
On 2010-01-10, Spehro Pefhany wrote:

[ ... ]

I miss LASCRs (light activated SCRs), SBS (Silicon bilateral
switches), tunnel diodes, germanium transistors, clean air, tuna,
Taiwan.

How many here have ever heard of a "binistor"? A 4-pin bistable
device which apparently never took off in the market. It was a
four-layer device (like a SCR -- except that it had another pin to allow
turning it off.

IIRC, Transitron gave it the designation 3N21. I could look it
up in the old Transitron data book -- but I don't know where that is at
the moment. :-)

Enjoy,
DoN.


Sounds like a GTO:
http://en.wikipedia.org/wiki/Gate_turn-off_thyristor
http://www.youtube.com/watch?v=o_FSicQWimU

--Winston

Made by Pontiac?

Don Foreman wrote:
On Sun, 10 Jan 2010 16:17:37 -0800, Winston
wrote:

(...)

Sounds like a GTO:
http://en.wikipedia.org/wiki/Gate_turn-off_thyristor
http://www.youtube.com/watch?v=o_FSicQWimU

--Winston

Made by Pontiac?

First one, no. Second one, yes.

--Winston


--

You taught me tolerance, kindness, generosity and optimism.

By example, yes?

In article ,
"DoN. Nichols" wrote:

On 2010-01-10, Brian Lawson wrote:
On 10 Jan 2010 23:23:50 GMT, "DoN. Nichols"
wrote:

3N21


Hey DoN,

http://www.americanmicrosemi.com/information/spec/?ss_pn=3N21

O.K. Germanium means that I have given the wrong part number.
It was a silicon device. I wonder what those 3N devices were, how they
earned the leading 3 instead of 2. Transitron used it as a count of
junctions (e.g. one less than the number of leads.

The xNyy pattern is from a JAN standard, if I recall. I think that the
x is one less than the number of terminals, the then assumption being
that one must have at least two terminals. I don't think that the
number of junctions was considered, the intent being to treat the device
as a black box.

I would have guessed that 3N21 was an optocoupler, or a SCR with all
four layers connected. However, it seems to be an obsolete transistor
type made by Sylvania and Western Electric:
http://homepages.nildram.co.uk/~wylie/wanted.htm. However, it turns
out to be a Germanium switching transistor:
http://www.datasheetarchive.com/3N21-datasheet.html.

Joe Gwinn

Don Foreman wrote:

On Sat, 09 Jan 2010 10:04:25 -0500, Spehro Pefhany
wrote:


At the other end of the scale, do you have any of those 5V switchers
laying around? Last I looked, a surplus place near me has a big stack
of brand new compact 5V wall plug switchers for about $2-3.

The surplus store near me has some but they want more like 12 bux for
them. Arrgghh, highway robbery! I found a little 2.4VA 8VRMS 60-Hz
xfmr in my goodiebox that should work nicely.


http://www.mpja.com/powersupply.asp usually has some good deals.


--
Greed is the root of all eBay.

Winston wrote:

Jim Wilkins wrote:

(...)

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.

A sales guy I knew, frustrated with the noises made by electronic
engineers dubbed their language "di double - E feedback".


That is the kind of salesman no one wants to deal with, if their IQ
is over 70. The last electronics 'salesman' I worked with would visit
both engineering and production test to see what was going on, and had
started with the company as a tech. If he didn't know the answer to a
customer's question, he knew who to call to get the right information.

Your 'sales guy' should have gone back to selling used cars, or to
putting lids on drinks at McDonalds.


--
Greed is the root of all eBay.

Jim Wilkins wrote:

On Jan 9, 8:46 pm, "Michael A. Terrell"
wrote:
Jim Wilkins wrote:

I mentioned earlier working for both MEs and EEs. They don't
understand each others' secret language and aren't always too happy
that I do.

It's more fun when you toss in the other MEs (Manufacturing
Engineering) to the mix. Each group thinks they are the only ones who
matter.

I've only worked directly for one Manufacturing Engineer and he was
happy to let me design circuits and otherwise do as I pleased.

But yes, they can all become very defensive and territorial. Sometimes
after the hardware is functional I work for the software group as a
test engineer. Another can of worms opened.


I worked for an 'Engineering to order' company on products from 12
year old designs to cutting edge. All three departments didn't want to
budge, fearing they would be giving up something. As a production test
tech, I could stop the shipment of anything that didn't pass the tests.
or was too close to the edge on all parameters. A few times of almost
missing shipment dates soon had them paying attention.

The result was design changes to make testing easier and with better
repeatability. New & modified test fixtures, and test software. Better
test procedures, including rewriting some written by a Hispanic EE and
translated into very ambiguous English.

One EE had designed and built the only automated test fixture in the
plant, but he totally screwed up the software. He went ballistic when I
not only rewrote the software, but added more tests and some
diagnostics. My boss had a fit when I added two sound effects to the
software. One was a low pitched fog horn whenever the software detected
a problem. The other sounded like winning an early video game when the
board passed.


--
Greed is the root of all eBay.