Diac Testing...

[Cursitor Doom]

On Sun, 11 Jun 2023 11:04:09 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 07:26:32 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 10:51:48 +0100, Cursitor Doom <cd@notformail.com
wrote:

Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

Build an R-C relaxation oscillator, with a scope or an LED as the
discharge indicator.

I wanted a warning light for a high-voltage low-current power supply,
and the easy fix was a rc oscillator with a diac and an LED. It makes
bright blinks with very low current.

https://www.dropbox.com/sh/yaqbi52vbpo6uyc/AABPAczwj1zv26-fwI4LvJyha?dl=0

Does that link work?

Yup, all fine now, thanks.
Fred\'s not happy because I don\'t buy into his climate alarmism. I\'ve
posted incontrovertible evidence that the CO2 levels aren\'t changing
one iota in the long term - and for some reason that seems to really
annoy and upset him.

 

[John Larkin]

On Sun, 11 Jun 2023 20:08:38 +0100, Cursitor Doom <cd@notformail.com>
wrote:

On Sun, 11 Jun 2023 10:53:54 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 17:40:19 +0100, Cursitor Doom <cd@notformail.com
wrote:

On Sun, 11 Jun 2023 09:00:08 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 14:46:23 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
cd@notformail.com> wrote in <fmfb8iph1k37tsp9b6bgdu8cud7mj6r4h0@4ax.com>:

On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichpwagner@hotmail.com> wrote in <u649d7$2m93o$1@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?

Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

I like coin envelopes in plastic or cardboard bins.

I can write stuff on the envelopes and they stack nicely.

https://www.dropbox.com/scl/fi/z7x8p7agql2z2g6i08djk/Parts_1.JPG?raw=1

https://www.dropbox.com/scl/fi/ccgusd68typ3j6m8aenls/Parts_2.JPG?raw=1


Dropbox won\'t let me sign in to see your pix, unfortunately, John.
Dunno why; never had this issue before.

Does this work?

https://www.dropbox.com/scl/fi/z7x8p7agql2z2g6i08djk/Parts_1.JPG?dl=0&rlkey=qq83sb5v0bc93j1rarg31dalo

Yes, no problem - and the others too.
Yours is quite similar to mine, but much neater and better organised.
Mine\'s like the aftermath of an atom bomb explosion. I\'ll post some
pix later if time permits. I need to be shamed into action to do
something about it anyway. Hopefully a public shaming will galvanize
me into sorting it all out.

I\'m a parts pack rat. The little things are managable, but big stuff
(heat sinks, transformers, breadboards, oscilloscopes) are more
difficult.

 

[ehsjr]

On 6/11/2023 2:04 PM, John Larkin wrote:

On Sun, 11 Jun 2023 07:26:32 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 10:51:48 +0100, Cursitor Doom <cd@notformail.com
wrote:

Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

Build an R-C relaxation oscillator, with a scope or an LED as the
discharge indicator.

I wanted a warning light for a high-voltage low-current power supply,
and the easy fix was a rc oscillator with a diac and an LED. It makes
bright blinks with very low current.

https://www.dropbox.com/sh/yaqbi52vbpo6uyc/AABPAczwj1zv26-fwI4LvJyha?dl=0

Does that link work?

Yes.

 

[Cursitor Doom]

On Sun, 11 Jun 2023 11:04:09 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 07:26:32 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 10:51:48 +0100, Cursitor Doom <cd@notformail.com
wrote:

Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

Build an R-C relaxation oscillator, with a scope or an LED as the
discharge indicator.

I wanted a warning light for a high-voltage low-current power supply,
and the easy fix was a rc oscillator with a diac and an LED. It makes
bright blinks with very low current.

https://www.dropbox.com/sh/yaqbi52vbpo6uyc/AABPAczwj1zv26-fwI4LvJyha?dl=0

Does that link work?

Here you go:

https://disk.yandex.com/d/c8oUimfFG6EvZg

 

[John Larkin]

On Sun, 11 Jun 2023 21:16:47 +0100, Cursitor Doom <cd@notformail.com>
wrote:

On Sun, 11 Jun 2023 11:04:09 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 07:26:32 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 10:51:48 +0100, Cursitor Doom <cd@notformail.com
wrote:

Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

Build an R-C relaxation oscillator, with a scope or an LED as the
discharge indicator.

I wanted a warning light for a high-voltage low-current power supply,
and the easy fix was a rc oscillator with a diac and an LED. It makes
bright blinks with very low current.

https://www.dropbox.com/sh/yaqbi52vbpo6uyc/AABPAczwj1zv26-fwI4LvJyha?dl=0

Does that link work?


Here you go:

https://disk.yandex.com/d/c8oUimfFG6EvZg

Here\'s my office:

https://www.dropbox.com/s/u9f6htqb2f5f38k/Office.jpg?dl=0

 

[Tabby]

On Sunday, 11 June 2023 at 15:46:31 UTC+1, Jan Panteltje wrote:

On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
c...@notformail.com> wrote in <fmfb8iph1k37tsp9b...@4ax.com>:
On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichp...@hotmail.com> wrote in <u649d7$2m93o$1...@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?
Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

In case of doubt in mulimeter test you could see what it is on the markings if not a DIAC?
I give you guys that a curve tracer is nice, designed one one day, pulsed at that to prevent overheating...
Bit of software these days to store the trace.
Would not take a lot of money..
An ebay search for curvetracer kit gives many hits:
https://www.ebay.ca/sch/i.html?_nkw=curve+tracer+kit
but only goes from -10 to +10V if I read the specs right.
modify it with some HV transistors....


The crude way is to use a triac light dimmer and try the uknown thing in it, if it dimms OK!
But could blow up some low voltage components.
Best is to keep your stuff sorted.

a dimmer would also work using a zener.

 

[Cursitor Doom]

On Sun, 11 Jun 2023 13:30:53 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 21:16:47 +0100, Cursitor Doom <cd@notformail.com
wrote:

On Sun, 11 Jun 2023 11:04:09 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 07:26:32 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 10:51:48 +0100, Cursitor Doom <cd@notformail.com
wrote:

Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

Build an R-C relaxation oscillator, with a scope or an LED as the
discharge indicator.

I wanted a warning light for a high-voltage low-current power supply,
and the easy fix was a rc oscillator with a diac and an LED. It makes
bright blinks with very low current.

https://www.dropbox.com/sh/yaqbi52vbpo6uyc/AABPAczwj1zv26-fwI4LvJyha?dl=0

Does that link work?


Here you go:

https://disk.yandex.com/d/c8oUimfFG6EvZg

Here\'s my office:

https://www.dropbox.com/s/u9f6htqb2f5f38k/Office.jpg?dl=0

Your office is lovely. That typewriter could use a service though.

 

[John Larkin]

On Sun, 11 Jun 2023 14:19:42 -0700 (PDT), Tabby <tabbypurr@gmail.com>
wrote:

On Sunday, 11 June 2023 at 15:46:31 UTC+1, Jan Panteltje wrote:
On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
c...@notformail.com> wrote in <fmfb8iph1k37tsp9b...@4ax.com>:
On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichp...@hotmail.com> wrote in <u649d7$2m93o$1...@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?
Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

In case of doubt in mulimeter test you could see what it is on the markings if not a DIAC?
I give you guys that a curve tracer is nice, designed one one day, pulsed at that to prevent overheating...
Bit of software these days to store the trace.
Would not take a lot of money..
An ebay search for curvetracer kit gives many hits:
https://www.ebay.ca/sch/i.html?_nkw=curve+tracer+kit
but only goes from -10 to +10V if I read the specs right.
modify it with some HV transistors....


The crude way is to use a triac light dimmer and try the uknown thing in it, if it dimms OK!
But could blow up some low voltage components.
Best is to keep your stuff sorted.

a dimmer would also work using a zener.

I don\'t think so. If the lamp lights at all, and you don\'t fry
something, both unlikely, control will be awful.

 

[Tabby]

On Sunday, 11 June 2023 at 23:46:41 UTC+1, John Larkin wrote:

On Sun, 11 Jun 2023 14:19:42 -0700 (PDT), Tabby <tabb...@gmail.com
wrote:
On Sunday, 11 June 2023 at 15:46:31 UTC+1, Jan Panteltje wrote:
On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
c...@notformail.com> wrote in <fmfb8iph1k37tsp9b...@4ax.com>:
On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichp...@hotmail.com> wrote in <u649d7$2m93o$1...@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?
Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

In case of doubt in mulimeter test you could see what it is on the markings if not a DIAC?
I give you guys that a curve tracer is nice, designed one one day, pulsed at that to prevent overheating...
Bit of software these days to store the trace.
Would not take a lot of money..
An ebay search for curvetracer kit gives many hits:
https://www.ebay.ca/sch/i.html?_nkw=curve+tracer+kit
but only goes from -10 to +10V if I read the specs right.
modify it with some HV transistors....


The crude way is to use a triac light dimmer and try the uknown thing in it, if it dimms OK!
But could blow up some low voltage components.
Best is to keep your stuff sorted.

a dimmer would also work using a zener.
I don\'t think so. If the lamp lights at all, and you don\'t fry
something, both unlikely, control will be awful.

Basic circuit function would still be there, the differences would be
- slower turn on increases triac Pdiss, not going to be noticed with a low power load
- asymmetric control, with earlier triggering on one of the half cycles, resulting in less dimming per degree of knob reduction.

 

[Phil Hobbs]

On 2023-06-11 12:58, Cursitor Doom wrote:

On Sun, 11 Jun 2023 09:00:08 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 11 Jun 2023 14:46:23 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
cd@notformail.com> wrote in <fmfb8iph1k37tsp9b6bgdu8cud7mj6r4h0@4ax.com>:

On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichpwagner@hotmail.com> wrote in <u649d7$2m93o$1@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?

Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

I like coin envelopes in plastic or cardboard bins.

I can write stuff on the envelopes and they stack nicely.

https://www.dropbox.com/scl/fi/z7x8p7agql2z2g6i08djk/Parts_1.JPG?raw=1

https://www.dropbox.com/scl/fi/ccgusd68typ3j6m8aenls/Parts_2.JPG?raw=1



Anyway, assuming your system matches your description, I have
inherited a shit-ton of components which are also stored in plastic
envelopes with permanent marker to say what they are. The problem I
find at any rate - YMMV - is that the volume of the plastic vastly
exceeds the volume of the components within, making for very bulky
storage requirements. Also, if the marker has been used on the outside
of the plastic, it gets scuffed off very easily and has to be
re-written over in a surprisingly short time. The only solution I\'ve
found that *really* is permanent, is those newer Dymo label makers.
Not the embossed type, but the thermographically printed variety. They
really do last indefinitely. The Chinese make cheap cartridge refills
for these and they work just as well as the originals.

https://tinyurl.com/2p93vff3

Old-timey ballpoint pen is very permanent, and ballpoints can be induced
to write on most polyethylene bags. Industrial Sharpies are much better
than the normal ones, but don\'t stand abrasion as well as ballpoint.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 2023-06-11 14:00, John Larkin wrote:

On Sun, 11 Jun 2023 10:05:41 -0700 (PDT), Fred Bloggs
bloggs.fredbloggs.fred@gmail.com> wrote:

On Sunday, June 11, 2023 at 10:26:45?AM UTC-4, John Larkin wrote:
On Sun, 11 Jun 2023 10:51:48 +0100, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD
Build an R-C relaxation oscillator, with a scope or an LED as the
discharge indicator.

I wanted a warning light for a high-voltage low-current power supply,
and the easy fix was a rc oscillator with a diac and an LED. It makes
bright blinks with very low current.

https://www.dropbox.com/sh/yaqbi52vbpo6uyc/AABPAczwj1zv26-fwI4LvJyha?dl=0

If you can\'t think of method that requires him to put one lead under his tongue, you\'re not doing anything.

You are being helpful, as usual.
A relative of mine once tried testing a 67.5V dry battery on his tongue,
like a 9-volt.

Only once.

Cheers

Phil Hobbs

 

[John Larkin]

On Sun, 11 Jun 2023 18:14:54 -0700 (PDT), Tabby <tabbypurr@gmail.com>
wrote:

On Sunday, 11 June 2023 at 23:46:41 UTC+1, John Larkin wrote:
On Sun, 11 Jun 2023 14:19:42 -0700 (PDT), Tabby <tabb...@gmail.com
wrote:
On Sunday, 11 June 2023 at 15:46:31 UTC+1, Jan Panteltje wrote:
On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
c...@notformail.com> wrote in <fmfb8iph1k37tsp9b...@4ax.com>:
On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichp...@hotmail.com> wrote in <u649d7$2m93o$1...@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?
Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

In case of doubt in mulimeter test you could see what it is on the markings if not a DIAC?
I give you guys that a curve tracer is nice, designed one one day, pulsed at that to prevent overheating...
Bit of software these days to store the trace.
Would not take a lot of money..
An ebay search for curvetracer kit gives many hits:
https://www.ebay.ca/sch/i.html?_nkw=curve+tracer+kit
but only goes from -10 to +10V if I read the specs right.
modify it with some HV transistors....


The crude way is to use a triac light dimmer and try the uknown thing in it, if it dimms OK!
But could blow up some low voltage components.
Best is to keep your stuff sorted.

a dimmer would also work using a zener.
I don\'t think so. If the lamp lights at all, and you don\'t fry
something, both unlikely, control will be awful.

Basic circuit function would still be there, the differences would be
- slower turn on increases triac Pdiss, not going to be noticed with a low power load
- asymmetric control, with earlier triggering on one of the half cycles, resulting in less dimming per degree of knob reduction.

A triac needs a lot of trigger current. The diac does that.

Draw a circuit with values and post it here. We can discuss it.

 

[Jan Panteltje]

On a sunny day (Sun, 11 Jun 2023 09:58:11 -0700 (PDT)) it happened Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote in
<4dd46fee-c5fa-455e-8649-cdc85c9f07d4n@googlegroups.com>:

On Sunday, June 11, 2023 at 7:51:06 AM UTC-4, Jan Panteltje wrote:
On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichp...@hotmail.com> wrote in <u649d7$2m93o$1...@dont-email.me>:
On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious=

parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to=

differentiate the two groups? The usual component testers don\'t seem=

to work with diacs and just flag them as \'unknown or faulty part\' or=

occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an=

oscilloscope capable of XY tracing (like an old cathode ray based scope)=

a resistor of say 1 or 2 kohm and a mains transformer with a secondary=

of approx 30V rms to get a peak voltage comfortably above 40V. Wire the=

unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input=

to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular=

diodes from diacs and give a good estimate of zener volatge upto 43V or =
so.

piglet
Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I think most modern multimeters have a diode tester, which is a 500uA curre=
nt source, usually, with COM negative. The meter displays VF in forward mod=
e and OL (over limit) in reverse mode. There was something about the the ol=
d d\'arsonval meters in ohms mode that put the positive voltage on NEG lead =
and negative voltage on the POS lead. I\'m sure they had their reasons, but =
it\'s something to be aware of when diode testing with those things.

Yes, I have some of these (was recommended by someone here) was 4 for 10 dollars or so?
Still going strong:
https://panteltje.nl/pub/chinese_multimeter_img_3159.jpg
That diode symbol is also the \'beep\' continuity (short) test...
But should not be a problem, a DIAC should do OL both ways.

 

[Jan Panteltje]

On a sunny day (Sun, 11 Jun 2023 14:19:42 -0700 (PDT)) it happened Tabby
<tabbypurr@gmail.com> wrote in
<1cfb9142-9565-49cf-bc69-da51fe73910bn@googlegroups.com>:

On Sunday, 11 June 2023 at 15:46:31 UTC+1, Jan Panteltje wrote:
On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
c...@notformail.com> wrote in <fmfb8iph1k37tsp9b...@4ax.com>:
On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichp...@hotmail.com> wrote in <u649d7$2m93o$1...@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?
Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

In case of doubt in mulimeter test you could see what it is on the markings if not a DIAC?
I give you guys that a curve tracer is nice, designed one one day, pulsed at that to prevent overheating...
Bit of software these days to store the trace.
Would not take a lot of money..
An ebay search for curvetracer kit gives many hits:
https://www.ebay.ca/sch/i.html?_nkw=curve+tracer+kit
but only goes from -10 to +10V if I read the specs right.
modify it with some HV transistors....


The crude way is to use a triac light dimmer and try the uknown thing in it, if it dimms OK!
But could blow up some low voltage components.
Best is to keep your stuff sorted.

a dimmer would also work using a zener.

Have not tried it, yes interesting, but full dimming range ?

 

[Jan Panteltje]

On a sunny day (Sun, 11 Jun 2023 17:44:45 +0100) it happened Cursitor Doom
<cd@notformail.com> wrote in <eaub8il4p0046egkm5k4c6c428r85sfg2a@4ax.com>:

On Sun, 11 Jun 2023 14:46:23 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
cd@notformail.com> wrote in <fmfb8iph1k37tsp9b6bgdu8cud7mj6r4h0@4ax.com>:

On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichpwagner@hotmail.com> wrote in <u649d7$2m93o$1@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?

Only as complicated as you make it,

I invariably over-complicate everything. Just can\'t help myself.

you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

In case of doubt in mulimeter test you could see what it is on the markings if not a DIAC?
I give you guys that a curve tracer is nice, designed one one day, pulsed at that to prevent overheating...
Bit of software these days to store the trace.
Would not take a lot of money..
An ebay search for curvetracer kit gives many hits:
https://www.ebay.ca/sch/i.html?_nkw=curve+tracer+kit
but only goes from -10 to +10V if I read the specs right.
modify it with some HV transistors....


The crude way is to use a triac light dimmer and try the uknown thing in it, if it dimms OK!
But could blow up some low voltage components.

That\'s a novel approach you have there, Jan! ;-) However, there *is*
some merit in it I have to admit.


Best is to keep your stuff sorted.

This is hamfest stuff so came unsorted as these things do. Are you
going to any good hamfests this summer? I believe there\'s a biggie
coming up in Germany in a couple of weeks.

Have not been to one in ages, not very active with ham radio ATM.
Old house yes, satellite link to QO100
Here the dish is mounted very high and I have to climb a ladder and risk my life....
Also since some years you have to pay a yearly contribution to the government to use the spectrum
so to speak, seriously considering given up my callsign. Back to being a pirate!
Maybe that hobby had its years.
The 70 cm band is mostly truckers here.... like 27 MHz once was,
repeaters exist for north east and west Netherlands etc.

Internet has taken over much of it all...
But when WW3 starts, and the bombs fall, maybe that old shortwave stuff I still have will come in handy
to see where - and if any humming beans are still around.. ;-)

How far do you get with a decent WiFi set and antenna?
But we will see.... I have a marine license too and that may come in handy when sailing away to a remote island
when all of Europe is radioactive after Putin nukes Kiev or Ukraine hits that nucleaer plant there.
OTOH who is going to enforce any license when all of society is no longer...

As to hamfests, ebay has been my main component source now for many years.
And some local shops that basically also sell ebay stuff but have it in stock.
The circuits I just design and solder together.. write the software, like this for example:
https://panteltje.nl/panteltje/raspberry_pi_dvb-s_transmitter/
Evariste after that did one better and did it _all_ in software:
https://github.com/F5OEO/rpidatv

My hat off to that!

 

[Jan Panteltje]

On a sunny day (Sun, 11 Jun 2023 09:00:08 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<4grb8i55q5fm5at27f6g1r2aq3epkltmof@4ax.com>:

On Sun, 11 Jun 2023 14:46:23 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
cd@notformail.com> wrote in <fmfb8iph1k37tsp9b6bgdu8cud7mj6r4h0@4ax.com>:

On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichpwagner@hotmail.com> wrote in <u649d7$2m93o$1@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?

Only as complicated as you make it,
you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

I like coin envelopes in plastic or cardboard bins.

I can write stuff on the envelopes and they stack nicely.

https://www.dropbox.com/scl/fi/z7x8p7agql2z2g6i08djk/Parts_1.JPG?raw=1

https://www.dropbox.com/scl/fi/ccgusd68typ3j6m8aenls/Parts_2.JPG?raw=1

I get a sign up screen on both links?

 

[Jan Panteltje]

On a sunny day (Sun, 11 Jun 2023 10:53:54 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<7g2c8ihnijdv4q5mrmd373hh2a1lvcph9b@4ax.com>:

Does this work?

https://www.dropbox.com/scl/fi/z7x8p7agql2z2g6i08djk/Parts_1.JPG?dl=0&rlkey=qq83sb5v0bc93j1rarg31dalo

Yes

 

[Jan Panteltje]

On a sunny day (Sun, 11 Jun 2023 10:49:28 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<l52c8i95qsk6q0ks5ll0ilghb0mspvvvsj@4ax.com>:

Dropbox keeps changing, which can be annoying.

Try these:

https://www.dropbox.com/scl/fi/z7x8p7agql2z2g6i08djk/Parts_1.JPG?dl=0&rlkey=qq83sb5v0bc93j1rarg31dalo

https://www.dropbox.com/scl/fi/ccgusd68typ3j6m8aenls/Parts_2.JPG?dl=0&rlkey=5kr5s1u9n7r008r19vraew668

Yes OK.

 

[Phil Allison]

Tabby wrote:
--------------------

a dimmer would also work using a zener.

** ROTFL



.....Phil

 

[Cursitor Doom]

On Mon, 12 Jun 2023 05:39:44 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On a sunny day (Sun, 11 Jun 2023 17:44:45 +0100) it happened Cursitor Doom
cd@notformail.com> wrote in <eaub8il4p0046egkm5k4c6c428r85sfg2a@4ax.com>:

On Sun, 11 Jun 2023 14:46:23 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 13:35:32 +0100) it happened Cursitor Doom
cd@notformail.com> wrote in <fmfb8iph1k37tsp9b6bgdu8cud7mj6r4h0@4ax.com>:

On Sun, 11 Jun 2023 11:50:57 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 11 Jun 2023 11:58:47 +0100) it happened piglet
erichpwagner@hotmail.com> wrote in <u649d7$2m93o$1@dont-email.me>:

On 11/06/2023 10:51 am, Cursitor Doom wrote:
Gentlemen,

I have a large assortment of diodes of all descriptions in my copious
parts inventory. However, there are some diacs in amongst them as I
recently discovered to my cost in terms of wasted time. Now these
diacs don\'t obey the customary blue marking and are visually
indistinguishable from regular rectifier diodes. To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes. Can any of you gurus come up with a quick and simple test to
differentiate the two groups? The usual component testers don\'t seem
to work with diacs and just flag them as \'unknown or faulty part\' or
occasionally as zener diodes, which is even worse. Any ideas?

CD

You could make a simple curve tracer. Since diacs can have trigger
voltages of 30-40V it needs to be a bit higher voltage. You will need an
oscilloscope capable of XY tracing (like an old cathode ray based scope)
a resistor of say 1 or 2 kohm and a mains transformer with a secondary
of approx 30V rms to get a peak voltage comfortably above 40V. Wire the
unknown diode in series with the resistor across the transformer.
Connect the scope common to the diode-resistor junction and the X input
to the diode-transformer junction and Y input to the
resistor-transformer junction. The curves will help you identify regular
diodes from diacs and give a good estimate of zener volatge upto 43V or so.

piglet

Using a normal multimeter on the ohms range,
1.5 V and 9 V meter batteries assumed,
would show at least some conduction for diodes in one direction,
but not for DIACs in any direction (a few uA).
Would filter out non-diodes fast.
https://en.m.wikipedia.org/wiki/DIAC

?

I like your idea for its simplicity, Jan. But I also like Erich\'s
suggestion for its more rigorous approach. The main problem AISI with
using a multimeter is that some of those assorted components may have
Shockley diodes among them, and they will confuse this test and appear
to be diacs. It\'s a complicated life, isn\'t it?

Only as complicated as you make it,

I invariably over-complicate everything. Just can\'t help myself.

you could use different boxes for different stuff,
or I also do use labelled plastic bags in icecream boxes re-purposed for component storage:
https://panteltje.nl/pub/boxes_1_IMG_4429.JPG
https://panteltje.nl/pub/ice_cream_boxes_IMG_6540.JPG

In case of doubt in mulimeter test you could see what it is on the markings if not a DIAC?
I give you guys that a curve tracer is nice, designed one one day, pulsed at that to prevent overheating...
Bit of software these days to store the trace.
Would not take a lot of money..
An ebay search for curvetracer kit gives many hits:
https://www.ebay.ca/sch/i.html?_nkw=curve+tracer+kit
but only goes from -10 to +10V if I read the specs right.
modify it with some HV transistors....


The crude way is to use a triac light dimmer and try the uknown thing in it, if it dimms OK!
But could blow up some low voltage components.

That\'s a novel approach you have there, Jan! ;-) However, there *is*
some merit in it I have to admit.


Best is to keep your stuff sorted.

This is hamfest stuff so came unsorted as these things do. Are you
going to any good hamfests this summer? I believe there\'s a biggie
coming up in Germany in a couple of weeks.

Have not been to one in ages, not very active with ham radio ATM.
Old house yes, satellite link to QO100
Here the dish is mounted very high and I have to climb a ladder and risk my life....
Also since some years you have to pay a yearly contribution to the government to use the spectrum
so to speak, seriously considering given up my callsign. Back to being a pirate!
Maybe that hobby had its years.
The 70 cm band is mostly truckers here.... like 27 MHz once was,
repeaters exist for north east and west Netherlands etc.

Internet has taken over much of it all...
But when WW3 starts, and the bombs fall, maybe that old shortwave stuff I still have will come in handy
to see where - and if any humming beans are still around.. ;-)

Same here! SW will be the only game in town post nuclear exchange,
although there won\'t be many of us left to use it.