Chip with simple program for Toy

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.
Click to expand...

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
 
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.
Click to expand...
This is a silicon point-contact diode, essentially the same as the
WWII parts, expect that they get to use modern, very pure silicon:

http://www.micrometrics.com/pdfs/PC_SXBandMixer.pdf

Skyworks makes some very low capacitance (below 0.5 pF) schottkies
that are similar.


This is 300 mV *max* at 100 mA, so should be down there. I think the
schottky curve is sorta similar to the silicon PN curve, which is 60
mV per decade of current.

http://www.centralsemi.com/PDFs/products/CMHSH5-2L.PDF

I posted some WWII diode curves elsewhere, well under 200 mV at 1 mA.

Gee.

John
 
Rich Grise inscribed thus:

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
Click to expand...
Yes ! I have some devices that were made in the mid to late 40's.

Also if I can find them I have some pre war point contact detectors that
have screw terminals on the ends.

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

JF
 
John Fields wrote:

JosephKK wrote:

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.
Click to expand...
Sounds about right.

I have a book here about the develpoment of active devices for radar and it's
quite unambiguous about silicon being used for microwave diodes. The early
work was actually done by GEC and BTH of the UK in conjuction with military
R&D.

As ever the Americans refined the manufacturing process. The early ones were
virtually 'hand made'.

Graham
 
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.
Click to expand...
---
Just to make sure it wasn't an anomaly, I measured 10 more and here's
what I got:

If Vf
mA V
-------+-------+
1.000 0.1495
1.000 0.1350
1.000 0.1525
1.000 0.1344
1.000 0.1495
1.000 0.1355
1.000 0.1510
1.000 0.1532
1.000 0.1496
1.000 0.1370


The equipment was set up like this:



+-------[WAVETEK 27XT]---[10k]---+----------+
|+ |A |+
[HP 6216A] [DUT] [FLUKE 8060A]
|- | |-
+--------------------------------+----------+


The 8060A draws 25ľA on the 2 volt range, so the current out of the
6216A was set to 1.025mA for every reading in order to force 1.000mA
through the 1N5817s.

Turns out the power supply was impossible to adjust spot on, so I put
the 10k resistor in there to give me fewer ľA per degree of rotation
of the knob. Worked great.

JF
 
On Wed, 23 Apr 2008 09:50:13 -0500, John Fields
<jfields@austininstruments.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.

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

---
Just to make sure it wasn't an anomaly, I measured 10 more and here's
what I got:

If Vf
mA V
-------+-------+
1.000 0.1495
1.000 0.1350
1.000 0.1525
1.000 0.1344
1.000 0.1495
1.000 0.1355
1.000 0.1510
1.000 0.1532
1.000 0.1496
1.000 0.1370


The equipment was set up like this:



+-------[WAVETEK 27XT]---[10k]---+----------+
|+ |A |+
[HP 6216A] [DUT] [FLUKE 8060A]
|- | |-
+--------------------------------+----------+


The 8060A draws 25ľA on the 2 volt range, so the current out of the
6216A was set to 1.025mA for every reading in order to force 1.000mA
through the 1N5817s.

Turns out the power supply was impossible to adjust spot on, so I put
the 10k resistor in there to give me fewer ľA per degree of rotation
of the knob. Worked great.

JF
Click to expand...
Most DVM's seem to output 1 mA on the diode-test range. I don't know
how much of a convention that is. They do seem to disagree on how much
voltage they'll indicate: some display the Vf of an LED, some say open
or overload or whatever.

John
 
On Tue, 22 Apr 2008 21:40:49 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.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.

This is a silicon point-contact diode, essentially the same as the
WWII parts, expect that they get to use modern, very pure silicon:

http://www.micrometrics.com/pdfs/PC_SXBandMixer.pdf

Skyworks makes some very low capacitance (below 0.5 pF) schottkies
that are similar.


This is 300 mV *max* at 100 mA, so should be down there. I think the
schottky curve is sorta similar to the silicon PN curve, which is 60
mV per decade of current.

http://www.centralsemi.com/PDFs/products/CMHSH5-2L.PDF

I posted some WWII diode curves elsewhere, well under 200 mV at 1 mA.

Gee.

John
Click to expand...
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!

John
 
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!
Click to expand...
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
 
On Apr 22, 4:03 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 22 Apr 2008 14:22:47 -0700 (PDT), Tom Bruhns <k7...@msn.com
wrote:



On Apr 22, 1:42 pm, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 22 Apr 2008 20:19:49 GMT, Rich Grise <r...@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

I'd question that "was well understood" part. The description in the
Buderi book makes it pretty clear that before 1940, people working
with semiconductors (key being at Bell Labs) didn't have a very deep
understanding of what was going on. It was only in late '39 and 40
that they got serious ideas that they could actually control what was
an essentially empirically-understood phenomenon by changing the
amount and type of impurity. The description of things going on then
as "increasingly curious properties" of silicon doesn't seem to fit
very well with "well understood." But maybe Buderi didn't do a very
good job documenting that particular work, and missed the depth to
which the phenomena were understood.

Cheers,
Tom

Just checking the footnotes in the radlab book, it looks like most of
the serious theorizing (ie, stuff that worked) was published between
1939 and 1942, "about 1940" by my standards. Potential barrier
diagrams and Fermi levels and such were in books published in 1940.
Mott and Schottky seem to have published the first non-silly diode
theory stuff (non-backwards!) in 1939 and 1940. This got a lot more
serious between 1940 and 1943 as MIT poured in money and talent.

John
Click to expand...
Thanks for the references, John. Sounds like Buderi, who certainly
had access to all that, might have put it in somewhat different light
than he did, perhaps something along the lines of, "though much
theoretical work had been done by 1940, it remained to discover how to
apply it in practice." He does make it clear that researchers all the
way up through development of the transistor didn't fully appreciate
what they could do with potential barrier diagrams and Fermi levels
and the like. As I scan through the book, I see multiple references
to events over several years where there was clear puzzlement, limited
understanding, and/or disagreement about what was going on in observed
effects around semiconductors. The serious search for a solid-state
amplifier (based on semiconductor materials) was started apparently at
least by 1936 at Bell Labs, and I suppose it was there and at a very
small number of universities where much of the published work you cite
was begun or carried out. Too bad that it's a bit late to be asking
the people actually involved in the work! (Wish I'd had the foresight
and time to ask my uncle more about the work he did at RadLab. :-( )

Cheers,
Tom
 
On Wed, 23 Apr 2008 11:46:09 -0700 (PDT), Tom Bruhns <k7itm@msn.com>
wrote:

On Apr 22, 4:03 pm, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 22 Apr 2008 14:22:47 -0700 (PDT), Tom Bruhns <k7...@msn.com
wrote:



On Apr 22, 1:42 pm, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 22 Apr 2008 20:19:49 GMT, Rich Grise <r...@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

I'd question that "was well understood" part. The description in the
Buderi book makes it pretty clear that before 1940, people working
with semiconductors (key being at Bell Labs) didn't have a very deep
understanding of what was going on. It was only in late '39 and 40
that they got serious ideas that they could actually control what was
an essentially empirically-understood phenomenon by changing the
amount and type of impurity. The description of things going on then
as "increasingly curious properties" of silicon doesn't seem to fit
very well with "well understood." But maybe Buderi didn't do a very
good job documenting that particular work, and missed the depth to
which the phenomena were understood.

Cheers,
Tom

Just checking the footnotes in the radlab book, it looks like most of
the serious theorizing (ie, stuff that worked) was published between
1939 and 1942, "about 1940" by my standards. Potential barrier
diagrams and Fermi levels and such were in books published in 1940.
Mott and Schottky seem to have published the first non-silly diode
theory stuff (non-backwards!) in 1939 and 1940. This got a lot more
serious between 1940 and 1943 as MIT poured in money and talent.

John

Thanks for the references, John. Sounds like Buderi, who certainly
had access to all that, might have put it in somewhat different light
than he did, perhaps something along the lines of, "though much
theoretical work had been done by 1940, it remained to discover how to
apply it in practice." He does make it clear that researchers all the
way up through development of the transistor didn't fully appreciate
what they could do with potential barrier diagrams and Fermi levels
and the like. As I scan through the book, I see multiple references
to events over several years where there was clear puzzlement, limited
understanding, and/or disagreement about what was going on in observed
effects around semiconductors. The serious search for a solid-state
amplifier (based on semiconductor materials) was started apparently at
least by 1936 at Bell Labs, and I suppose it was there and at a very
small number of universities where much of the published work you cite
was begun or carried out. Too bad that it's a bit late to be asking
the people actually involved in the work! (Wish I'd had the foresight
and time to ask my uncle more about the work he did at RadLab. :-( )

Cheers,
Tom
Click to expand...

The radlab boys observed a number of interesting things that they
didn't have the time to pursue. One was negative resistance in diodes,
and another was diode mixers that had signal power gain, the precursor
to the parametric amplifier. Tunneling was known, too, a long time
before Esaki discovered the tunnel diode.

All that is in one book out of 27. In about 5 years, these guys
invented modern electronics.

John
 
On Wed, 23 Apr 2008 16:27:21 -0400, John Popelish <jpopelish@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.
Click to expand...
"Back diode" is interesting, too. They are, to my knowledge, the only
germanium diodes made using an ic-type mask process, and about the
only Ge diodes still made at all, except for photodiodes of course.
They are still the best microwave detectors.

John
 
On Wed, 23 Apr 2008 07:52:46 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 23 Apr 2008 09:50:13 -0500, John Fields
jfields@austininstruments.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.

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

---
Just to make sure it wasn't an anomaly, I measured 10 more and here's
what I got:

If Vf
mA V
-------+-------+
1.000 0.1495
1.000 0.1350
1.000 0.1525
1.000 0.1344
1.000 0.1495
1.000 0.1355
1.000 0.1510
1.000 0.1532
1.000 0.1496
1.000 0.1370


The equipment was set up like this:



+-------[WAVETEK 27XT]---[10k]---+----------+
|+ |A |+
[HP 6216A] [DUT] [FLUKE 8060A]
|- | |-
+--------------------------------+----------+


The 8060A draws 25ľA on the 2 volt range, so the current out of the
6216A was set to 1.025mA for every reading in order to force 1.000mA
through the 1N5817s.

Turns out the power supply was impossible to adjust spot on, so I put
the 10k resistor in there to give me fewer ľA per degree of rotation
of the knob. Worked great.

JF

Most DVM's seem to output 1 mA on the diode-test range.
Click to expand...
---
Into a short.
---

don't know how much of a convention that is.
Click to expand...
---
I have 5, and on the DIODE TEST function they put out:

EMCO DMR3250 1.3229 mA

SPECO DMR2500 1.2045 mA

WAVETEK DM5XL 1.0387 mA

WAVETEK 27XT 1.0098 mA

FLUKE 8060A 0.943 mA

So it seems to be pretty conventional.
---

They do seem to disagree on how much
voltage they'll indicate: some display the Vf of an LED, some say open
or overload or whatever.
Click to expand...
---
Depends on the Vf of the LED, I suspect. All of mine display the
voltage drop of the DUT, whether it's a resistor or a diode or
whatever, and display overload when the voltage gets to be > 1.999V.

Here are the results of an experiment I just finished running:


+-------------------------------------+
| |
+--[SOURCE]--------[R]--------[LOAD]--+

VOLTS OHMS MILLIAMPS

DMR3520 0.123 0 1.3229
2.000 12300 0.1773

DMR2500 0.100 0 1.2045
2.000 1913 0.616

DM5XL 0.106 0 1.0387
2.000 6072 0.3273

27XT 0.101 0 1.0098
2.000 5423 0.3662

8060A 0.095 0 0.943
2.000 2056 0.934

The series resistance was a Clarostat 240C decade resistor box, and
for the first four entries the load was the Fluke 8060A. In the last
one it was the Wavetek 27XT.

The test was run by measuring the current from the source (the meter
switched to the DIODE TEST function), recording it, then recording the
voltage indicated on the source's display, then switching in
resistance until the source's display indicated overload.

Interesting to note that the Fluke has an almost constant current
source feeding the DUT, while none of the others do.

JF
 
On Thu, 24 Apr 2008 00:58:28 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

"John Fields"

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


** But you well knew that Motorola describe them as having " Extremely low
Vf " - now didn't you ??

http://www.onsemi.com/pub_link/Collateral/1N5817-D.PDF
Click to expand...
---
Actually, I didn't, but thanks for the clue.
---


BTW:

how hot did you make it get first ?
Click to expand...
---
Well, I showed it my penis...

JF
 
John Larkin wrote:
On Wed, 23 Apr 2008 16:27:21 -0400, John Popelish <jpopelish@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.

"Back diode" is interesting, too. They are, to my knowledge, the only
germanium diodes made using an ic-type mask process, and about the
only Ge diodes still made at all, except for photodiodes of course.
They are still the best microwave detectors.
Click to expand...
Yes, interesting, but not very much like the characteristics
of 1N23.

--
Regards,

John Popelish
 
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
Click to expand...
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
 
sert wrote:

I was reading an analysis of this CE amplifier:

http://xs126.xs.to/xs126/08174/complete168.png

My problem with the analysis was in the DC section. The author
removes the circuit that lies beyond the capacitors and he
then claims that he replaces the R1, R2 voltage divider with
their Thevenin equivalent Vbb, Rb and reaches the following
circuit for the DC signals:

http://xs126.xs.to/xs126/08174/dc_equiv421.png

With:

Rb = R1//R2

Vbb = Vcc*R2/(R1+R2)
Click to expand...
Correct.


Now, I was sure that the Thevenin theorem states that you can
replace a part of a circuit between two nodes. Are the nodes
in question here the Vcc and Ground? But the whole DC circuit
lies between Vcc and Ground. Also, we have the base current
leaving between R1 and R2. We could ignore that current since
it's very small but he doesn't ignore in in the DC equivalent.
Click to expand...
The effect of base current drawn will be modelled by Rb in the Thevenin
equivalent version.


I'm lost here, can someone provide a helping hand? How do we
reach the second circuit starting from the first?
Click to expand...
I think your main problem may be in your understanding of the Thevenon
equivalent. Its whole purpose to is to simplify by reducing the number
of components. I think you need to explain more of *what* it is you
don't exactly understand.

Graham
 
Now, I was sure that the Thevenin theorem states that you can
replace a part of a circuit between two nodes. Are the nodes
in question here the Vcc and Ground?
Click to expand...
No, the nodes "in question" are between the base terminal and ground.
 
I was reading an analysis of this CE amplifier:

http://xs126.xs.to/xs126/08174/complete168.png

My problem with the analysis was in the DC section. The author
removes the circuit that lies beyond the capacitors and he
then claims that he replaces the R1, R2 voltage divider with
their Thevenin equivalent Vbb, Rb and reaches the following
circuit for the DC signals:

http://xs126.xs.to/xs126/08174/dc_equiv421.png

With:

Rb = R1//R2

Vbb = Vcc*R2/(R1+R2)

Now, I was sure that the Thevenin theorem states that you can
replace a part of a circuit between two nodes. Are the nodes
in question here the Vcc and Ground? But the whole DC circuit
lies between Vcc and Ground. Also, we have the base current
leaving between R1 and R2. We could ignore that current since
it's very small but he doesn't ignore in in the DC equivalent.

I'm lost here, can someone provide a helping hand? How do we
reach the second circuit starting from the first?
Click to expand...
View in a fixed-width font such as Courier.

..
..
..
..
.. Vcc VB
.. | current thru R1= I = IB + --
.. | 1 R2
.. |
.. I2 | [R1] IB |
.. v | -> |/ Vcc= I1 x R1 + VB
.. +---------|
.. VB | + |> VB
.. -- | [R2] | = (IB + -- ) x R1 + VB
.. R2 v | VB R2
.. | -
.. --- Vcc- IB x R1
.. making VB= -----------
.. R1
.. 1 + --
.. R2
..
.. Vcc IB x R1
.. Then rewriting VB= ------- - -------
.. R1 R1
.. 1 + -- 1 + --
.. R2 R2
..
..
..
.. R2 R1 x R2
.. making VB = Vcc x ------- - IB x -------
.. R1 + R2 R1 + R2
..
..
..
.. same result as :
..
..
.. IB | R2
.. -> |/ where VBO=Vcc x -------
.. ---[Rb]-----| R1 + R2
.. | + |>
.. |+ | R1 x R2
.. --- VBO VB and RB= -------
.. - - R1 + R2
.. |-
.. |
.. ---
..
..
..
.. but VBO and RB are Thevenin equivalent of VCC and R1,R2
..
..
.. so the results are the same using either the TE or solving
..
..
.. from scratch....
..
..
..
 
I was reading an analysis of this CE amplifier:

http://xs126.xs.to/xs126/08174/complete168.png

My problem with the analysis was in the DC section. The author
removes the circuit that lies beyond the capacitors and he
then claims that he replaces the R1, R2 voltage divider with
their Thevenin equivalent Vbb, Rb and reaches the following
circuit for the DC signals:

http://xs126.xs.to/xs126/08174/dc_equiv421.png

With:

Rb = R1//R2

Vbb = Vcc*R2/(R1+R2)

Now, I was sure that the Thevenin theorem states that you can
replace a part of a circuit between two nodes. Are the nodes
in question here the Vcc and Ground? But the whole DC circuit
lies between Vcc and Ground. Also, we have the base current
leaving between R1 and R2. We could ignore that current since
it's very small but he doesn't ignore in in the DC equivalent.

I'm lost here, can someone provide a helping hand? How do we
reach the second circuit starting from the first?
Click to expand...
View in a fixed-width font such as Courier.


..
..
..
..
.. Vcc VB
.. | current thru R1= I = IB + --
.. | 1 R2
.. |
.. I1 | [R1] IB |
.. v | -> |/ Vcc= I1 x R1 + VB
.. +---------|
.. VB | + |> VB
.. -- | [R2] | = (IB + -- ) x R1 + VB
.. R2 v | VB R2
.. | -
.. --- Vcc- IB x R1
.. making VB= -----------
.. R1
.. 1 + --
.. R2
..
.. Vcc IB x R1
.. Then rewriting VB= ------- - -------
.. R1 R1
.. 1 + -- 1 + --
.. R2 R2
..
..
..
.. R2 R1 x R2
.. making VB = Vcc x ------- - IB x -------
.. R1 + R2 R1 + R2
..
..
..
.. same result as :
..
..
.. IB | R2
.. -> |/ where VBO=Vcc x -------
.. ---[Rb]-----| R1 + R2
.. | + |>
.. |+ | R1 x R2
.. --- VBO VB and RB= -------
.. - - R1 + R2
.. |-
.. |
.. ---
..
..
..
.. but VBO and RB are Thevenin equivalent of VCC and R1,R2
..
..
.. so the results are the same using either the TE or solving
..
..
.. from scratch....
..
..
..
 
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