Re: [TCML] Dan Mccauley, et al staccato PCB SC2026

[futuret@xxxxxxx]

Hi Jim,

Apparently the SCR never sees the full plate voltage.  This
permits it to survive despite a 1200V or lower max voltage
rating.  SCR's are said to be more robust in general than
triacs.  Triacs don't offer any advantage.  I haven't had
any problem with turning off the SCR's.  They turn off
during the negative 60Hz half cycle.  I had problems with
triacs blowing out, but no problems with SCR's.  Of course
my SCR's had a much higher voltage and current rating,
so that's part of the reason.  I used an IR50RIA120 SCR,
but it was overkill actually.  This work was done a number
of years ago, so others may have more information/findings
at this time.

Cheers,
John


-----Original Message-----
From: Jim Mora <wavetuner@xxxxxxxxx>
To: 'Tesla Coil Mailing List' <tesla@xxxxxxxxxx>
Sent: Thu, Jun 25, 2009 5:53 pm
Subject: [TCML] Dan Mccauley, et al staccato PCB SC2026



Hi All,

I am going to put together the group buy printed and silk screened PCB 
and
staccato electronics circa 3-6-03 before I loose all the stuff. This 
will be
to pulse a 4x 833C tube coil. It has been boxed since 2003 - parts from
DigiKey. Is there any mods, chages, or enhancements I should know about?

What would be a hearty SCR or triac selection for this application? 
Will I
need an additional special driver for the gate? A suggested SCR or Triac
that will do this comfortably would be much appreciated! It would be 
seeing
up to 4-5kv @ ~ 2.2amps to ground (all filaments/cathodes are common. I 
have
heard problems of turning off the SCR once gated which is how they were
intended as I recall. Would a triac be a better choice?

Thanks, Jim Mora
________________________________________
"I do not think that the wireless waves I have discovered will have any
practical application"
Heinrich Hertz

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