Diac Testing...

C

Cursitor Doom

Guest
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
 
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
Click to expand...

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
 
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
Click to expand...

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

?
 
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

?
Click to expand...

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?
 
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
Click to expand...

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
 
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?
Click to expand...

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.
 
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
Click to expand...

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
 
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
Click to expand...

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

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.
Click to expand...

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.
 
On Sunday, June 11, 2023 at 8:35:41 AM UTC-4, Cursitor Doom wrote:
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.... To prevent future
fuck-ups, I need to identify the diacs and remove them from the
diodes.

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

So, get a 30VAC transformer, resistor in series with some clips or other diode-friendly
connectors, and hook your o-scope X axis across the device under test, and
the Y axis across the resistor (common point of those two) and the transformer output
on the two non-common terminals. That\'ll show diode, Zeners of modest voltage,
and most diacs for what they are, by tracing I-V characteristic.
Resistors in the 15kohm range should be
safe (but maybe not for LEDs or germanium, because of the reverse currents)..
Curve tracers aren\'t a difficult item; the old Huntron tracker was, IMHO, an
excessively overengineered device for this purpose.
 
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

?
Click to expand...

I think most modern multimeters have a diode tester, which is a 500uA current source, usually, with COM negative. The meter displays VF in forward mode and OL (over limit) in reverse mode. There was something about the the old 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.
 
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
Click to expand...

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
 
On Sunday, June 11, 2023 at 12:58:34 PM UTC-4, Cursitor Doom wrote:
On Sun, 11 Jun 2023 09:00:08 -0700, John Larkin
jla...@highlandSNIPMEtechnology.com> wrote:
On Sun, 11 Jun 2023 14:46:23 GMT, Jan Panteltje <al...@comet.invalid
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

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
Click to expand...

You want to protect components in long term storage from ambient air, especially where you live.
 
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
Click to expand...

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

That\'s strange. It\'s supposed to be public.

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
 
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.
Click to expand...

Does this work?

https://www.dropbox.com/scl/fi/z7x8p7agql2z2g6i08djk/Parts_1.JPG?dl=0&rlkey=qq83sb5v0bc93j1rarg31dalo
 
On Sun, 11 Jun 2023 17:58:24 +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



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
Click to expand...

I just write on the paper coin envelopes. And I often tape the Mouser
or some such label on the back so we know who we got the parts from.
There\'s room for some test notes too.

The coin envelopes stack nicely. Plastic bags can be a mess.
 
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.
Click to expand...

You are being helpful, as usual.
 
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
Click to expand...

Does that link work?
 
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
Click to expand...

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.
 
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