Chip with simple program for Toy

[John Larkin]

On Wed, 23 Apr 2008 20:17:28 GMT, "Ken Fowler" <ko6no@yahoo.com>
wrote:

On 22-Apr-2008, Michael Black <et472@ncf.ca> wrote:

On Sat, 12 Apr 2008 17:51:10 +0200, ronwer wrote:

I am doing a study into the early use of silicon diodes in radar and
communication equipment during the Second World War.

Did they even _have_ silicon diodes in WWII? I remember when they
announced the first transistor, some time in the early 1950's.


I started working on military surplus radios and consumer broadcast radios
in 1954, went to US Navy ET school in 1956, and spent a few years reparing
communications and radar equipment manufactured in the 1947 - 1960 era.
Other than the 1N21 and 1N23 diodes used in radar receivers, which I
believe were point-contact germanium devices, the first signal diodes I saw
were the 1N34 types used in an IFF decoder. They were relatively large
axial packages with a hexagonal body shape. All other places where a diode
was necessary, vacuum tubes were used for small signals and Selemium-oxide
plate rectifiers were used in power supplies. By 1959, when I went to
school on the AN/URC-32 SSB Transceiver, both germanium and silicon diodes
and transistors were in wide use in new military radio circuits. From my
experience, no silicon diodes were used at any time before 1950 in USN
military equipment. The first consumer transistorized radios I remember
were sometime around 1960. I wish I still had my Allied Radio Catalogs
from 1954 and later. You could buy a Raytheon CK721 transistor for
something like $3. I think the CK722 cost more. By 1965, you could buy
grab bags of transistors and diodes at Radio Shack for $3.

Good Memories,
Ken Fowler, KO6NO

The 1N21 and 1N23 were actually silicon point-contact diodes. The
other common 1940's rectifier was copper oxide, used for small-signal
rectification, notably for the AC ranges of VOM's.

John

 

[Bob Monsen]

"*paolino Q*" <senzaparole@tiscali.it> wrote in message
news:4811dc53$0$29973$5fc30a8@news.tiscali.it...

I have found ,for bicycles of my niece , schematic of a typical kojak
siren but without list of components .
I thought of finding , by experiment , the close frequency and getting
the just values of resistences and capacitors but I cannot well get them ;
does anyone , that bought the kit kemo or similar one , know them ? The
scheme is here :

http://attach.mynl.it/img?id=NzQ0Ng

These are my tried values :

R1=R4=R7=R10=R5== 560 OHM
R2=r3=R8= R6=r9= 22000 , 2200 ,33000 ,68000

c5=c6 = 22 nano F

C2=C3= 47 micro F

Transistors =bc547 c & bd242

R1 12k
R2 100k
R3 100k
R4 10k
R5 47k
R6 100k
R7 10k
R8 100k
R9 100k
R10 10k

C1 22uF
C2 0.47uF
C3 0.47uF
C4 0.1uF
C5 0.01uF
C6 0.01uF

Instead of using R11 into T5, you need more drive. Use another npn in a
darlington configuration:


View in fixed-width font:

12 o----------------------o------.
| |
| |
| |
| | __ /|
| '--| | |
| .--|__| |
R11 | | \|
___ |/ |
From -----|___|------| |
Oscillator |> |
100k | |
| |/
'----|
| |>
.-. |
10k | | |
| | |
'-' |
| |
| |
0 o-----------------------o------'
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


That should scream pretty annoyingly.

Regards,
Bob Monsen

 

[Stephen J. Rush]

On Fri, 25 Apr 2008 14:10:20 -0700, JeffM wrote:

Paul E. Schoen wrote:
I found a free newsreader http://news.interbulletin.com. This looks
like a much better way to have web-based access to usenet than Google
Groups.

Again: No.

JeffM wrote:
[...]for *reading*
http://news.elektroda.net/scielectronicsdesign-vf6.html [...]
http://www.electronicskb.com/Default.aspx latency is very low.
[...]No clickable links[...]
They also add a 1-line footer ad to posts made from there.

Here is another Web-based site for reading the group. It allows
posting--but adds a 3-LINE FOOTER AD to posts. They update in bursts, so
latency for reading can be 2 hours. I can't say what posting latency is
like--but I wouldn't hold my breath.

The page design has one really stupid premise: On my Gecko browser,
the leftmost 35% of the screen is essentially blank space. After
applying NukeAnything (or Platypus), it's much better.

On the main page, posts are arranged by posting time so there are
multiple instances of the same thread (like interbulletin.com--which I
don't like).

Long Subject lines are truncated.
Subject lines with non-7-bit characters look like crap (mostly spam
anyway).
...and they delete topics marked as OT --but *keep* REAL spam (Morons)
...or maybe they just don't properly index a lot of posts (see
"timestamps", below).

On pages for reading posts, the threading is nicely indicated --but
timestamps are a mish-mash.
Web links are clickable; Usenet Message IDs AREN'T.

While they make an effort to retain spacing, it's a proportional font
--so unless you reconfigure your browser, ASCII prints will be junk.

Why not just get a real newsreader, like Pan or Agent? There is more to
the Internet than the Web.

 

[Jim Thompson]

On Fri, 25 Apr 2008 14:53:00 -0700 (PDT), JeffM <jeffm_@email.com>
wrote:

Paul E. Schoen wrote:
[...]a much better way to have web-based access to usenet
than Google Groups.

JeffM wrote:
http://news.elektroda.net/scielectronicsdesign-vf6.html [...]
http://www.electronicskb.com/Default.aspx latency is very low.

::JeffM wrote:
::http://www.talkaboutelectronicequipment.com/group/
sci.electronics.design

Stephen J. Rush wrote:
Why not just get a real newsreader, like Pan or Agent?
There is more to the Internet than the Web.

Jim Thompson has a list of at least 65 people
who for one reason or another are limited to Port 80 access.
The most common reasons are:
1) Port 119 blocked by IT.
2) Not allowed to add software to the computer.

I might smirk and ask... If port 119 is blocked by IT, are you not
goofing off on company time by reading news ?

Larkin and Fields and I report to no other...

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 | |
| Voice480)460-2350 Fax:Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

 

[JeffM]

Paul E. Schoen wrote:
I found a free newsreader http://news.interbulletin.com.
This looks like a much better way to have web-based access to usenet
than Google Groups.

Again: No.

JeffM wrote:

for *reading*
http://news.elektroda.net/scielectronicsdesign-vf6.html
[...]
http://www.electronicskb.com/Default.aspx
latency is very low.
[...]No clickable links[...]
They also add a 1-line footer ad to posts made from there.

Here is another Web-based site for reading the group.
It allows posting--but adds a 3-LINE FOOTER AD to posts.
They update in bursts, so latency for reading can be 2 hours.
I can't say what posting latency is like--but I wouldn't hold my
breath.

The page design has one really stupid premise:
On my Gecko browser,
the leftmost 35% of the screen is essentially blank space.
After applying NukeAnything (or Platypus), it's much better.

On the main page, posts are arranged by posting time
so there are multiple instances of the same thread
(like interbulletin.com--which I don't like).

Long Subject lines are truncated.
Subject lines with non-7-bit characters look like crap
(mostly spam anyway).
....and they delete topics marked as OT
--but *keep* REAL spam (Morons)
....or maybe they just don't properly index a lot of posts
(see "timestamps", below).

On pages for reading posts, the threading is nicely indicated
--but timestamps are a mish-mash.
Web links are clickable; Usenet Message IDs AREN'T.

While they make an effort to retain spacing, it's a proportional font
--so unless you reconfigure your browser, ASCII prints will be junk.

 

[JeffM]

JeffM wrote:

Paul E. Schoen wrote:
I found a free newsreader http://news.interbulletin.com.
This looks like a much better way to have web-based access to usenet
than Google Groups.

Again: No.

JeffM wrote:
[...]for *reading*
http://news.elektroda.net/scielectronicsdesign-vf6.html
[...]
http://www.electronicskb.com/Default.aspx
latency is very low.
[...]No clickable links[...]
They also add a 1-line footer ad to posts made from there.

Here is another Web-based site for reading the group.

....and, of course, I forgot the link:

http://www.talkaboutelectronicequipment.com/group/sci.electronics.design

It allows posting--but adds a 3-LINE FOOTER AD to posts.
They update in bursts, so latency for reading can be 2 hours.
I can't say what posting latency is like
--but I wouldn't hold my breath.

The page design has one really stupid premise:
On my Gecko browser,
the leftmost 35% of the screen is essentially blank space.
After applying NukeAnything (or Platypus), it's much better.

On the main page, posts are arranged by posting time
so there are multiple instances of the same thread
(like interbulletin.com--which I don't like).

Long Subject lines are truncated.
Subject lines with non-7-bit characters look like crap
(mostly spam anyway).
...and they delete topics marked as OT
--but *keep* REAL spam (Morons)
...or maybe they just don't properly index a lot of posts
(see "timestamps", below).

On pages for reading posts, the threading is nicely indicated
--but timestamps are a mish-mash.
Web links are clickable; Usenet Message IDs AREN'T.

While they make an effort to retain spacing, it's a proportional font
--so unless you reconfigure your browser, ASCII prints will be junk.

 

[Rich Webb]

On Fri, 25 Apr 2008 15:25:38 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

I might smirk and ask... If port 119 is blocked by IT, are you not
goofing off on company time by reading news ?

Absolutely, an appropriate amount of "goofing off" being necessary to
overall productivity and mental health. Some folks take smoke breaks,
some wander over to the coffee mess, some take a gander at usenet,
some do other things (darts, anyone?).

--
Rich Webb Norfolk, VA

 

[JeffM]

Paul E. Schoen wrote:
[...]a much better way to have web-based access to usenet
than Google Groups.

JeffM wrote:
http://news.elektroda.net/scielectronicsdesign-vf6.html [...]
http://www.electronicskb.com/Default.aspx latency is very low.

::JeffM wrote:

::http://www.talkaboutelectronicequipment.com/group/
sci.electronics.design

Stephen J. Rush wrote:

Why not just get a real newsreader, like Pan or Agent?
There is more to the Internet than the Web.

Jim Thompson has a list of at least 65 people
who for one reason or another are limited to Port 80 access.
The most common reasons are:
1) Port 119 blocked by IT.
2) Not allowed to add software to the computer.

 

[JosephKK]

On Wed, 23 Apr 2008 02:09:10 +0000 (UTC), don@manx.misty.com (Don
Klipstein) wrote:

In article <pd3t04l5i3gck6c4r87f0a51e2qr5hia0e@4ax.com>, JosephKK wrote:
On Sun, 20 Apr 2008 20:45:08 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On 21 Apr 2008 03:03:32 GMT, JosephKK <quiettechblue@yahoo.com> wrote:

On 20 Apr 2008 13:59:36 -0700, Don Bowey <dbowey@comcast.net>wrote:

Do you have a solid reference for that? "Credible" references I found
said they were silicon.

The most conclusive evidence i know of, is someone here who actually
put one to test and the result was germanium. A heck of a lot of
"official" or "authoritative" records are pure fertilizer.

What test?

V(f) @ 1 mA. Result < 180 mV. Thus Ge, not Si.

I have seen silicon schottky diodes that drop about .3 volt at 1 amp.

- Don Klipstein (don@misty.com)

Not arguing that. Would that diode make a good microwave detector?

 

[JosephKK]

On Tue, 22 Apr 2008 21:04:37 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 22 Apr 2008 18:17:10 -0700, JosephKK <quiettechblue@yahoo.com
wrote:

On Sun, 20 Apr 2008 20:45:08 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 21 Apr 2008 03:03:32 GMT, JosephKK <quiettechblue@yahoo.com
wrote:

On Sun, 20 Apr 2008 13:59:36 -0700, Don Bowey <dbowey@comcast.net
wrote:

On 4/20/08 11:26 AM, in article am2n04hciv1c0trs9vmfala4pf78ic80nb@4ax.com,
"JosephKK" <quiettechblue@yahoo.com> wrote:

On Sat, 12 Apr 2008 11:29:18 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 12 Apr 2008 11:24:19 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 12 Apr 2008 17:51:10 +0200, "ronwer"
neo.dymium.removethisfirst@dontwantspam.yahoo.com> wrote:

Hi!

I am doing a study into the early use of silicon diodes in radar and
communication equipment during the Second World War.

What I would be interested in is as follows:

-type numbers of the diodes

---
1N23 is a good place to start.

---
Oops... brain fart.

The 1N23 didn't appear until the '50's, I believe.

JF

Not only that it was germanium not silicon.

Do you have a solid reference for that? "Credible" references I found said
they were silicon.


The most conclusive evidence i know of, is someone here who actually
put one to test and the result was germanium. A heck of a lot of
"official" or "authoritative" records are pure fertilizer.

What test?

John

V(f) @ 1 mA. Result < 180 mV. Thus Ge, not Si.


Here are some curves from the RadLab book:

ftp://66.117.156.8/RadLabDiodes.JPG

ftp://66.117.156.8/RadDiode2.JPG

Your data point is dead on the point-contact Silicon diode curve.

John

Say what you will. I was playing with 1950's (or older) parts in the
1960's. All the datasheets back then said Ge. Compare proper
contemporaneous parts.

 

[JosephKK]

On Wed, 23 Apr 2008 02:20:37 +0000 (UTC), don@manx.misty.com (Don
Klipstein) wrote:

In article <hr5t04l9866fsp3r3s3sqgjcasco3fv1gr@4ax.com>, JosephKK wrote:
On Tue, 22 Apr 2008 13:42:10 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 22 Apr 2008 20:19:49 GMT, Rich Grise <rich@example.net> wrote:

On Sat, 12 Apr 2008 17:51:10 +0200, ronwer wrote:

I am doing a study into the early use of silicon diodes in radar and
communication equipment during the Second World War.

Did they even _have_ silicon diodes in WWII? I remember when they
announced the first transistor, some time in the early 1950's.

Thanks,
Rich

Yup. Most of the WWII radar diodes were silicon point-contact types,
Schottky diodes actually. The best 1943-vintage mixer parts were about
as good as any packaged schottky you can buy today... 0.2 Vf, 0.2 pF,
decent noise figures to 30 GHz.

The point-contact transistor was invented at Bell Labs in 1947. Most
of the relevant semiconductor theory - bandgaps, hole/electron
conduction, doping - was well understood by about 1940. The RadLab
guys didn't develop a PN-junction diode or the transistor because
their mandate was to develop radar to win the war.

John

Gee, John. Where do you get schottky diodes with V(f) below 0.2 V at
I(f) of 1 mA? All the ones i could find were over 0.33 V and mostly
0.4 to 0.5 V.

I am on a temporary setup now that does not have Acrobat, but I somewhat
remember Vishay-IR STPS1L30UPBF or 1N5818 dropping maybe .35 volt at 1
amp. These are 30 volt 1 amp Schottky rectifiers.

- Don Klipstein (don@misty.com)

Two things, these are "modern" parts. Did the equivalent exist in the
1940's or 1950's? Do they make good microwave detector diodes? I
think not. Use time and use appropriate devices for comparison.

 

[JosephKK]

On Wed, 23 Apr 2008 17:28:36 -0700 (PDT), Tom Bruhns <k7itm@msn.com>
wrote:

On Apr 23, 1:27 pm, John Popelish <jpopel...@rica.net> wrote:
John Larkin wrote:
Central CMMSH1-20 is a really tiny, about 1206 size, 1 amp 20 volt
schottky, great for small buck switchers; measures 201 mV at 1 mA. But
it's 280 pF!

I think if you do a Google search for "zero bias diode" you
will find things a lot more similar to 1N23 in electrical
characteristics.

--
Regards,

John Popelish

HSMS-2850 is about 0.2V @ 1mA, but it also has a PIV rating of just 2
volts. Capacitance is considerably less than that CMMSH1-20, though.
I don't have any point-contact diodes to compare it with, but can tell
you that it's useful for detecting RF down to a bit below 100uV,
possibly less if you're careful with thermal potentials and the like,
or chop the signal.

Cheers,
Tom

I am getting a little tired so may blatting about modern parts as if
they were available in the 1940'sand 1950's. The question is "What
were the original parts made of?"

Newer implementations is, at best, a side issue.

 

[JosephKK]

On Wed, 23 Apr 2008 08:51:25 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Tue, 22 Apr 2008 19:00:35 -0700, JosephKK <quiettechblue@yahoo.com
wrote:

On Tue, 22 Apr 2008 13:42:10 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 22 Apr 2008 20:19:49 GMT, Rich Grise <rich@example.net> wrote:

On Sat, 12 Apr 2008 17:51:10 +0200, ronwer wrote:

I am doing a study into the early use of silicon diodes in radar and
communication equipment during the Second World War.

Did they even _have_ silicon diodes in WWII? I remember when they
announced the first transistor, some time in the early 1950's.

Thanks,
Rich

Yup. Most of the WWII radar diodes were silicon point-contact types,
Schottky diodes actually. The best 1943-vintage mixer parts were about
as good as any packaged schottky you can buy today... 0.2 Vf, 0.2 pF,
decent noise figures to 30 GHz.

The point-contact transistor was invented at Bell Labs in 1947. Most
of the relevant semiconductor theory - bandgaps, hole/electron
conduction, doping - was well understood by about 1940. The RadLab
guys didn't develop a PN-junction diode or the transistor because
their mandate was to develop radar to win the war.

John

Gee, John. Where do you get schottky diodes with V(f) below 0.2 V at
I(f) of 1 mA? All the ones i could find were over 0.33 V and mostly
0.4 to 0.5 V.

---
I just pulled a random 1N5817 out of stock, put 1.000 milliamps
through it and measured 0.1383 volts across it.

JF

And what is the junction capacitance and does it make a good microwave
mixer?

 

[John Popelish]

JosephKK wrote:

On Wed, 23 Apr 2008 17:28:36 -0700 (PDT), Tom Bruhns <k7itm@msn.com
wrote:

HSMS-2850 is about 0.2V @ 1mA, but it also has a PIV rating of just 2
volts. Capacitance is considerably less than that CMMSH1-20, though.
I don't have any point-contact diodes to compare it with, but can tell
you that it's useful for detecting RF down to a bit below 100uV,
possibly less if you're careful with thermal potentials and the like,
or chop the signal.

Cheers,
Tom

I am getting a little tired so may blatting about modern parts as if
they were available in the 1940'sand 1950's. The question is "What
were the original parts made of?"

Newer implementations is, at best, a side issue.

Were germanium PN junction diodes of the period (or any
later period) good microwave detectors? I thought they were
pretty slow.

--
Regards,

John Popelish

 

[John Larkin]

On Sat, 26 Apr 2008 16:42:57 -0700, JosephKK <quiettechblue@yahoo.com>
wrote:

On Tue, 22 Apr 2008 21:04:37 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 22 Apr 2008 18:17:10 -0700, JosephKK <quiettechblue@yahoo.com
wrote:

On Sun, 20 Apr 2008 20:45:08 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 21 Apr 2008 03:03:32 GMT, JosephKK <quiettechblue@yahoo.com
wrote:

On Sun, 20 Apr 2008 13:59:36 -0700, Don Bowey <dbowey@comcast.net
wrote:

On 4/20/08 11:26 AM, in article am2n04hciv1c0trs9vmfala4pf78ic80nb@4ax.com,
"JosephKK" <quiettechblue@yahoo.com> wrote:

On Sat, 12 Apr 2008 11:29:18 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 12 Apr 2008 11:24:19 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 12 Apr 2008 17:51:10 +0200, "ronwer"
neo.dymium.removethisfirst@dontwantspam.yahoo.com> wrote:

Hi!

I am doing a study into the early use of silicon diodes in radar and
communication equipment during the Second World War.

What I would be interested in is as follows:

-type numbers of the diodes

---
1N23 is a good place to start.

---
Oops... brain fart.

The 1N23 didn't appear until the '50's, I believe.

JF

Not only that it was germanium not silicon.

Do you have a solid reference for that? "Credible" references I found said
they were silicon.


The most conclusive evidence i know of, is someone here who actually
put one to test and the result was germanium. A heck of a lot of
"official" or "authoritative" records are pure fertilizer.

What test?

John

V(f) @ 1 mA. Result < 180 mV. Thus Ge, not Si.


Here are some curves from the RadLab book:

ftp://66.117.156.8/RadLabDiodes.JPG

ftp://66.117.156.8/RadDiode2.JPG

Your data point is dead on the point-contact Silicon diode curve.

John

Say what you will. I was playing with 1950's (or older) parts in the
1960's. All the datasheets back then said Ge. Compare proper
contemporaneous parts.

Well, I'm sure your memory is more accurate than my books and
datasheets.

John

 

[John Popelish]

John Larkin wrote:

On Sat, 26 Apr 2008 16:42:57 -0700, JosephKK <quiettechblue@yahoo.com

Say what you will. I was playing with 1950's (or older) parts in the
1960's. All the datasheets back then said Ge. Compare proper
contemporaneous parts.


Well, I'm sure your memory is more accurate than my books and
datasheets.

I found an oral history from someone who was involved in the
research at the time (Art Uhlir Jr.). It is a bit
scattered, but very close to this discussion:
http://semiconductormuseum.com/Transistors/BellLabs/OralHistories/Uhlir/Uhlir_Index.htm

Bottom of page 10 gets to the 1N23.

--
Regards,

John Popelish

 

[Jeff Liebermann]

On Sat, 26 Apr 2008 16:42:57 -0700, JosephKK <quiettechblue@yahoo.com>
wrote:

Say what you will. I was playing with 1950's (or older) parts in the
1960's. All the datasheets back then said Ge. Compare proper
contemporaneous parts.

I still have a few 1N21 and 1N23 diodes used as mixers in ancient
X-band radar receivers. 2K25 klystron for a local oscillator.

Anyway, they're both silicon, not germanium. See:
<http://www.radiomuseum.org/tubes/tube_1n21a.html>
<http://www.radiomuseum.org/tubes/tube_1n23c.html>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jim Thompson]

On Sat, 26 Apr 2008 22:10:26 -0400, John Popelish <jpopelish@rica.net>
wrote:

John Larkin wrote:
On Sat, 26 Apr 2008 16:42:57 -0700, JosephKK <quiettechblue@yahoo.com

Say what you will. I was playing with 1950's (or older) parts in the
1960's. All the datasheets back then said Ge. Compare proper
contemporaneous parts.


Well, I'm sure your memory is more accurate than my books and
datasheets.

I found an oral history from someone who was involved in the
research at the time (Art Uhlir Jr.). It is a bit
scattered, but very close to this discussion:
http://semiconductormuseum.com/Transistors/BellLabs/OralHistories/Uhlir/Uhlir_Index.htm

Bottom of page 10 gets to the 1N23.

Corroborates my thought that they were probably point-contact.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

 

[Eeyore]

JosephKK wrote: John Larkin wrote:

Your data point is dead on the point-contact Silicon diode curve.

John

Say what you will. I was playing with 1950's (or older) parts in the
1960's. All the datasheets back then said Ge. Compare proper
contemporaneous parts.

Maybe they changed from Si to Ge ?

My IEE book on the subject says the early radar diodes were silicon though.

Graham

 

[John Fields]

On Sat, 26 Apr 2008 17:06:12 -0700, JosephKK <quiettechblue@yahoo.com>
wrote:

On Wed, 23 Apr 2008 08:51:25 -0500, John Fields
jfields@austininstruments.com> wrote:

On Tue, 22 Apr 2008 19:00:35 -0700, JosephKK <quiettechblue@yahoo.com
wrote:

On Tue, 22 Apr 2008 13:42:10 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 22 Apr 2008 20:19:49 GMT, Rich Grise <rich@example.net> wrote:

On Sat, 12 Apr 2008 17:51:10 +0200, ronwer wrote:

I am doing a study into the early use of silicon diodes in radar and
communication equipment during the Second World War.

Did they even _have_ silicon diodes in WWII? I remember when they
announced the first transistor, some time in the early 1950's.

Thanks,
Rich

Yup. Most of the WWII radar diodes were silicon point-contact types,
Schottky diodes actually. The best 1943-vintage mixer parts were about
as good as any packaged schottky you can buy today... 0.2 Vf, 0.2 pF,
decent noise figures to 30 GHz.

The point-contact transistor was invented at Bell Labs in 1947. Most
of the relevant semiconductor theory - bandgaps, hole/electron
conduction, doping - was well understood by about 1940. The RadLab
guys didn't develop a PN-junction diode or the transistor because
their mandate was to develop radar to win the war.

John

Gee, John. Where do you get schottky diodes with V(f) below 0.2 V at
I(f) of 1 mA? All the ones i could find were over 0.33 V and mostly
0.4 to 0.5 V.

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I just pulled a random 1N5817 out of stock, put 1.000 milliamps
through it and measured 0.1383 volts across it.

JF

And what is the junction capacitance and does it make a good microwave
mixer?

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Who cares?

Your statement that: "All the ones i could find were over 0.33 V and
mostly 0.4 to 0.5 V." had nothing to do with junction capacitance and
suitability for use as microwave mixers, all you were trying to do was
discredit Larkin by using bogus data. Which Schottky diodes were you
referring to, BTW?

JF