DIAC Bilateral Trigger

[bicycle6228]

I have a 56-70V Bilateral Trigger DIAC (basic data @
http://search.digikey.com/scripts/dksearch/dksus.dll?PName?Name=HT60-ND)
which I would like to test. I found what appeared to be a thorough
discussion of this device someplace on the web (can't find it now
though) but being an EE dropout it's all above me. Is there a fairly
simple way to do this with basic test equipment such as a VTVM, DC
power supply, signal generator &/or oscilloscope? Thanks for any ideas.

 

[petrus bitbyter]

"bicycle6228" <tomdempster@comcast.net> schreef in bericht
news:50651a98-41d7-4f8b-a93a-d135ea1ac1ab@e34g2000vbm.googlegroups.com...

I have a 56-70V Bilateral Trigger DIAC (basic data @
http://search.digikey.com/scripts/dksearch/dksus.dll?PName?Name=HT60-ND)
which I would like to test. I found what appeared to be a thorough
discussion of this device someplace on the web (can't find it now
though) but being an EE dropout it's all above me. Is there a fairly
simple way to do this with basic test equipment such as a VTVM, DC
power supply, signal generator &/or oscilloscope? Thanks for any ideas.

For a simple, static measurement you need a resistor of 47k, a voltmeter and
an adjustable power supply that ranges from 40-80Vdc. Put resistor and diac
in series and connect to the power supply. Connect the voltmeter cross the
diac then slowly raise the voltage. At some point between 56V and 70V the
diac will trip and the voltage on the meter goes down. Then you can lower
the voltage until the diac blocks again. According to the datasheet (at
least the one I have) the voltages need to be between 56V and 70V mentioned
already and may differ for about 4V as a maximum.

BTW Why do you need this information as you seem to lack the knowledge to do
something with it?

petrus bitbyter

 

[bicycle6228]

On Oct 5, 4:26 pm, "petrus bitbyter"
<pieterkraltlaatdit...@enditookhccnet.nl> wrote:

"bicycle6228" <tomdemps...@comcast.net> schreef in berichtnews:50651a98-41d7-4f8b-a93a-d135ea1ac1ab@e34g2000vbm.googlegroups.com...

I have a 56-70V Bilateral Trigger DIAC (basic data @
http://search.digikey.com/scripts/dksearch/dksus.dll?PName?Name=HT60-ND)
which I would like to test. I found what appeared to be a thorough
discussion of this device someplace on the web (can't find it now
though) but being an EE dropout it's all above me. Is there a fairly
simple way to do this with basic test equipment such as a VTVM, DC
power supply, signal generator &/or oscilloscope? Thanks for any ideas.

For a simple, static measurement you need a resistor of 47k, a voltmeter and
an adjustable power supply that ranges from 40-80Vdc. Put resistor and diac
in series and connect to the power supply. Connect the voltmeter cross the
diac then slowly raise the voltage. At some point between 56V and 70V the
diac will trip and the voltage on the meter goes down. Then you can lower
the voltage until the diac blocks again. According to the datasheet (at
least the one I have) the voltages need to be between 56V and 70V mentioned
already and may differ for about 4V as a maximum.

BTW Why do you need this information as you seem to lack the knowledge to do
something with it?

petrus bitbyter

Wow; thanks a ton for the response- exactly what I was looking for.

Why do you need this information
Here's the scenario: This DIAC I'd like to test is in an AC/DC

converter associated with a Klipsch Promedia 5.1 amplifier. The
circuit, if you're interested is described and diagramed here:
http://www.thompdale.com/bash_amplifier/5-1/5-1_bash_amp.htm
The circuit suffered a fairly massive failure of several parts,
including a power FET and a pair of zener diodes in close proximity
(both physically & electrically) to the DIAC, so I'm concerned about
its condition.
I will perform your test and replace the DIAC, depending on my
observations, along with a laundry list of other casualties.
Thanks again for your reply.

 

[petrus bitbyter]

"bicycle6228" <tomdempster@comcast.net> schreef in bericht
news:6f274fb8-011b-4efe-9000-d0abe432eee1@g1g2000pra.googlegroups.com...
On Oct 5, 4:26 pm, "petrus bitbyter"
<pieterkraltlaatdit...@enditookhccnet.nl> wrote:

"bicycle6228" <tomdemps...@comcast.net> schreef in
berichtnews:50651a98-41d7-4f8b-a93a-d135ea1ac1ab@e34g2000vbm.googlegroups.com...

I have a 56-70V Bilateral Trigger DIAC (basic data @
http://search.digikey.com/scripts/dksearch/dksus.dll?PName?Name=HT60-ND)
which I would like to test. I found what appeared to be a thorough
discussion of this device someplace on the web (can't find it now
though) but being an EE dropout it's all above me. Is there a fairly
simple way to do this with basic test equipment such as a VTVM, DC
power supply, signal generator &/or oscilloscope? Thanks for any ideas.

For a simple, static measurement you need a resistor of 47k, a voltmeter
and
an adjustable power supply that ranges from 40-80Vdc. Put resistor and
diac
in series and connect to the power supply. Connect the voltmeter cross the
diac then slowly raise the voltage. At some point between 56V and 70V the
diac will trip and the voltage on the meter goes down. Then you can lower
the voltage until the diac blocks again. According to the datasheet (at
least the one I have) the voltages need to be between 56V and 70V
mentioned
already and may differ for about 4V as a maximum.

BTW Why do you need this information as you seem to lack the knowledge to
do
something with it?

petrus bitbyter

Wow; thanks a ton for the response- exactly what I was looking for.

Why do you need this information
Here's the scenario: This DIAC I'd like to test is in an AC/DC

converter associated with a Klipsch Promedia 5.1 amplifier. The
circuit, if you're interested is described and diagramed here:
http://www.thompdale.com/bash_amplifier/5-1/5-1_bash_amp.htm
The circuit suffered a fairly massive failure of several parts,
including a power FET and a pair of zener diodes in close proximity
(both physically & electrically) to the DIAC, so I'm concerned about
its condition.
I will perform your test and replace the DIAC, depending on my
observations, along with a laundry list of other casualties.
Thanks again for your reply.

Oops. I made a big mistake! A diac that trips, keeps conducting until the
current falls below the hold level. So the voltage that makes a conducting
diac block again will be way below 40V. It will be around 1V as the hold
current is only about 25uA.

After this measurement you need to connect the diac in reverse and repeat.
Now the trip voltage needs to be within +/-4V of the first measurement.

If your power supply cannot go low enough, you may connect a 5M potmeter in
series with the resistor. Start measuring with the potmeter on 0. When the
diac trips lower the voltage and then increase the resistance of the
potmeter until the diac blocks again.

petrus bitbyter