SPICE models for diac?

Chaos Master · Jan 3, 2004

hello..

I'd like to know if some manufacturer ever created SPICE models for Diac's. I've
searched and didn't find one. Can someone post a model of diac on this group?

Thanks.

--
ChaosŽ - posting from Brazil
Please ask for e-mail address.

Jim Thompson · Jan 3, 2004

On Sat, 3 Jan 2004 17:52:25 -0200, Chaos Master
<ask_for_the_address@yahoo.com> wrote:

hello..

I'd like to know if some manufacturer ever created SPICE models for Diac's. I've
searched and didn't find one. Can someone post a model of diac on this group?

Thanks.

480)460-2350 | |
| E-mail Address at Website Fax

Spehro Pefhany · Jan 3, 2004

On Sat, 03 Jan 2004 13:15:14 -0700, the renowned Jim Thompson
<invalid@invalid.invalid> wrote:

On Sat, 3 Jan 2004 17:52:25 -0200, Chaos Master
ask_for_the_address@yahoo.com> wrote:

hello..

I'd like to know if some manufacturer ever created SPICE models for Diac's. I've
searched and didn't find one. Can someone post a model of diac on this group?

Thanks.

Is a Diac the same as a UJT/Unijunction-transistor?

...Jim Thompson

No, it's a bidirectional avalanche device- more like a triac. There's
one in every consumer light dimmer. Breaks down at something like 30V
(either way) depending on type and stays on until the current drops
below the holding current. The schematic symbol is a triac with no
gate connection.

The classic 2-wire light dimmer circuit is an adjustable R to a C
across the triac, with a diac from the C to the gate of the triac. The
triac gets pulses of opposite polarity every half-cycle, triggering it
in quadrants I and III.

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

Klaus Vestergaard Kragelu · Jan 3, 2004

"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message
news:f0eevv0a1vf3l4noldbiuajdhgsfqq7pi1@4ax.com...

On Sat, 03 Jan 2004 13:15:14 -0700, the renowned Jim Thompson
invalid@invalid.invalid> wrote:

On Sat, 3 Jan 2004 17:52:25 -0200, Chaos Master
ask_for_the_address@yahoo.com> wrote:

hello..

I'd like to know if some manufacturer ever created SPICE models for
Diac's. I've
searched and didn't find one. Can someone post a model of diac on this
group?

Thanks.

Is a Diac the same as a UJT/Unijunction-transistor?

...Jim Thompson

No, it's a bidirectional avalanche device- more like a triac. There's
one in every consumer light dimmer. Breaks down at something like 30V
(either way) depending on type and stays on until the current drops
below the holding current. The schematic symbol is a triac with no
gate connection.

The classic 2-wire light dimmer circuit is an adjustable R to a C
across the triac, with a diac from the C to the gate of the triac. The
triac gets pulses of opposite polarity every half-cycle, triggering it
in quadrants I and III.

I found this on the www.orcad.com site (->Site Map->Discuss->Pspice
Models->Search"DIAC"):

Topic: Spice Modeling
Author: Rabin
Date: 10/01/2002 5:20:41 PM

Subject: RE: DIAC
<< previous thread < previous next > next thread >>

There is a generic Triac model in PSpice's Thyristr
library which should be able to be modified for a Diac by disabling the gate
trigger circuitry in the model.

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Jim Thompson · Jan 3, 2004

On Sat, 03 Jan 2004 21:42:01 GMT, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

On Sat, 03 Jan 2004 13:15:14 -0700, the renowned Jim Thompson
invalid@invalid.invalid> wrote:

On Sat, 3 Jan 2004 17:52:25 -0200, Chaos Master
ask_for_the_address@yahoo.com> wrote:

hello..

I'd like to know if some manufacturer ever created SPICE models for Diac's. I've
searched and didn't find one. Can someone post a model of diac on this group?

Thanks.

Is a Diac the same as a UJT/Unijunction-transistor?

...Jim Thompson

No, it's a bidirectional avalanche device- more like a triac. There's
one in every consumer light dimmer. Breaks down at something like 30V
(either way) depending on type and stays on until the current drops
below the holding current. The schematic symbol is a triac with no
gate connection.

The classic 2-wire light dimmer circuit is an adjustable R to a C
across the triac, with a diac from the C to the gate of the triac. The
triac gets pulses of opposite polarity every half-cycle, triggering it
in quadrants I and III.

Best regards,
Spehro Pefhany

Aha! A solid-state equivalent of an NE-2 ?

Should be easy enough to make a subcircuit from a data sheet.

But do they make them anymore, or is it just a hacker component?

Surfing gave poor results, but finally stumbled onto Intusoft's stuff
at:

http://www.intusoft.com/models/demsidac.lib

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice

480)460-2350 | |
| E-mail Address at Website Fax

Spehro Pefhany · Jan 3, 2004

On Sat, 03 Jan 2004 15:26:09 -0700, the renowned Jim Thompson
<invalid@invalid.invalid> wrote:

Aha! A solid-state equivalent of an NE-2 ?

yup.

Should be easy enough to make a subcircuit from a data sheet.

The grandpappy of them all (can't you tell from that 1960's
typography?):

http://www1.jaycar.com.au/images_uploaded/ST2DIAC.PDF

Current production:
http://rocky.digikey.com/WebLib/Teccor/Web%20Data/Diac%20HT%20and%20ST%20Series.pdf

But do they make them anymore, or is it just a hacker component?

They make them, and they are cheap enough (<< 2 cents in 200K) but
AFAIK they are not really in wide use other than for triac triggering
in light dimmers. have them built-in.

Surfing gave poor results, but finally stumbled onto Intusoft's stuff
at:

http://www.intusoft.com/models/demsidac.lib

...Jim Thompson

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

Helmut Sennewald · Jan 4, 2004

"Chaos Master" <ask_for_the_address@yahoo.com> schrieb im Newsbeitrag
news:MPG.1a6111aff7fe97b29898f1@news.cis.dfn.de...

hello..

I'd like to know if some manufacturer ever created SPICE models for
Diac's. I've
searched and didn't find one. Can someone post a model of diac on this
group?

--- In LTspice@yahoogroups.com, "Roberto Poli" <roberto.poli@g...> ---

I need a model for 32V diac . Does anybody help me?

Hello "Chaos...",
I have answered a similar question a few months ago in the LTSPICE
Yahho group. The modeled DIAC triggers at +/-32V. I think the DIAC
symbol is already available in "Misc" folder of LTSPICE.

Best Regards,
Helmut

http://groups.yahoo.com/group/LTspice

Original text from thread 728 follows:

Hello ....,
I have done a big search about DIAC models with Google. It is really
strange how less useful information I could find for a SPICE model.
The best I have found is in the Intusoft newsletter Spring 2002.
http://www.spectrum-soft.com/news/spring2002/diac.shtm
http://www.spectrum-soft.com/news.shtm

I have made a DIAC model based on the Spectrum-Soft DIAC circuit plus the
data sheet from Teccor and my personal knowledge. You can adjust the
trigger voltage with the value of Rv. A greater value gives a higher
firing voltage. The breakover current is set by the value of R1 and
R2. Teccor specify 25uA, but I have seen another company specifying
100uA. With the 10kOhm values it is about 60uA. I believe this model
is very realistic compared with the data sheet.
http://www.teccor.com/web/PDF%20Files/Power/E8%20Diac.pdf
http://www.teccor.com/web/menuitems/downloads/datasheets.htm
http://www.teccor.com/asp/sitemap.asp?group=downloads

..SUBCKT DIAC32 1 2
RS 1 N006 10
RV N002 N004 510k
R1 N006 N002 10k
R2 N004 2 10k
Q4 N002 N005 2 0 PNP
Q2 N004 N003 N006 0 PNP
Q1 N003 N004 2 0 NPN
Q3 N005 N002 N006 0 NPN
D5 N002 N005 D
D6 N004 N003 D
..model NPN NPN(BF=20 TF=5u)
..model PNP PNP(BF=2 TF=5u)
..model D D
..ENDS

Best Regards
Helmut

Chaos Master · Jan 4, 2004

Klaus Vestergaard Kragelund[klauskvik@hotmail.com] said this in
sci.electronics.cad, at Sat, 3 Jan 2004 23:02:59 +0100, in article
<3ff73bfd$0$9746$edfadb0f@dread14.news.tele.dk>. I can prove it. And thus I reply:

There is a generic Triac model in PSpice's Thyristr
library which should be able to be modified for a Diac by disabling the gate
trigger circuitry in the model.

Interesting! I have some triac models here, from Teccor.
As I thought, the diac is a triac without gate.

--
ChaosŽ - posting from Brazil
Please ask for e-mail address.

Chaos Master · Jan 4, 2004

Helmut Sennewald[HelmutSennewald@t-online.de] said this in sci.electronics.cad, at
Sun, 4 Jan 2004 01:40:45 +0100, in article <bt7neb$e68$06$1@news.t-online.com>. I
can prove it. And thus I reply:

.SUBCKT DIAC32 1 2
[snip - DIAC model]
.ENDS

Thanks! I will try simulating this tomorrow, with SuperSpice.

--
ChaosŽ - posting from Brazil
Please ask for e-mail address.

Jim Thompson · Jan 4, 2004

On Sat, 3 Jan 2004 23:11:04 -0200, Chaos Master
<ask_for_the_address@yahoo.com> wrote:

said this in
sci.electronics.cad, at Sat, 3 Jan 2004 23:02:59 +0100, in article
3ff73bfd$0$9746$edfadb0f@dread14.news.tele.dk>. I can prove it. And thus I reply:

There is a generic Triac model in PSpice's Thyristr
library which should be able to be modified for a Diac by disabling the gate
trigger circuitry in the model.

Interesting! I have some triac models here, from Teccor.
As I thought, the diac is a triac without gate.

480)460-2350 | |
| E-mail Address at Website Fax

Kevin Aylward · Jan 4, 2004

Chaos Master wrote:

said this in
sci.electronics.cad, at Sun, 4 Jan 2004 01:40:45 +0100, in article
bt7neb$e68$06$1@news.t-online.com>. I can prove it. And thus I reply:

.SUBCKT DIAC32 1 2
[snip - DIAC model]
.ENDS

Thanks! I will try simulating this tomorrow, with SuperSpice.

There is a generic diac already in SS. If you do a shift-f you get the
find dialog. Typing diac brings it up, and you can place it from there
with the button. Its in the GenericDemos folder.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

That which is mostly observed, is that which replicates the most.
http://www.anasoft.co.uk/replicators/index.html

Chaos Master · Jan 4, 2004

Kevin Aylward[kevindotaylwardEXTRACT@anasoft.co.uk] said this in
sci.electronics.cad, at Sun, 4 Jan 2004 11:16:42 -0000, in article
<JCSJb.262$xx6.109@newsfep3-gui.server.ntli.net>. I can prove it. And thus I
reply:

There is a generic diac already in SS. If you do a shift-f you get the
find dialog. Typing diac brings it up, and you can place it from there
with the button. Its in the GenericDemos folder.

Ahhhh... I didn't knew this.
Thanks for all that replied.

--
ChaosŽ - posting from Brazil
Please ask for e-mail address.

Active8 · Jan 5, 2004

On Sat, 03 Jan 2004 23:12:52 GMT, speffSNIP@interlogDOTyou.knowwhat
said...

On Sat, 03 Jan 2004 15:26:09 -0700, the renowned Jim Thompson
invalid@invalid.invalid> wrote:

Aha! A solid-state equivalent of an NE-2 ?

yup.

Should be easy enough to make a subcircuit from a data sheet.

The grandpappy of them all (can't you tell from that 1960's
typography?):

http://www1.jaycar.com.au/images_uploaded/ST2DIAC.PDF

Current production:
http://rocky.digikey.com/WebLib/Teccor/Web%20Data/Diac%20HT%20and%20ST%20Series.pdf

But do they make them anymore, or is it just a hacker component?

They make them, and they are cheap enough (<< 2 cents in 200K) but
AFAIK they are not really in wide use other than for triac triggering
in light dimmers. have them built-in.

Is that what they're calling the silicon bilateral switch - a TRIAC
w/ built it DIAC sort of? not a pnpn npnp thing but 4 trannys, 2
zeners and 2 R's that act like a DIAC input TRIAC?

Now we have the SIDAC which looks like it's a DIAC with higher
breakover voltage. That lib below is sort of a hint and it opens
right up in model editor

Surfing gave poor results, but finally stumbled onto Intusoft's stuff
at:

http://www.intusoft.com/models/demsidac.lib

...Jim Thompson

Best regards,
Spehro Pefhany

--

Best Regards,
Mike

Chaos Master · Jan 6, 2004

Active8[mTHISREMOVEcolasono@earthlink.net] said this in sci.electronics.cad, at
Mon, 05 Jan 2004 19:45:59 GMT, in article
<MPG.1a6389004bbb724989839@news.east.earthlink.net>. I can prove it. And thus I
reply:

Is that what they're calling the silicon bilateral switch - a TRIAC
w/ built it DIAC sort of? not a pnpn npnp thing but 4 trannys, 2
zeners and 2 R's that act like a DIAC input TRIAC?

Typing "silicon bilateral switch" into Google gives some results (~300), which
include:

http://www.nteinc.com/specs/6400to6499/pdf/nte6403.pdf

and

www.pwrx.com/pages/newsflash/press_release.asp?file=180.htm

I am too tired to read them all, but I think this answers something about silicon
bilateral switches.

--
ChaosŽ - posting from Brazil
Please ask for e-mail address.

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