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RE: [VanDeGraaffGenerator] resistors value

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  • DOUG
    Hi Again Bert; will 3 of the 1 watt 200 ohm VR68 s work for R2? ... From: VanDeGraaffGenerator@yahoogroups.com [mailto:VanDeGraaffGenerator@yahoogroups.com] On
    Message 1 of 15 , May 7, 2013
    • 0 Attachment
      Hi Again Bert; will 3 of the 1 watt 200 ohm VR68's work for R2?

      -----Original Message-----
      From: VanDeGraaffGenerator@yahoogroups.com
      [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Bert Hickman
      Sent: Tuesday, May 07, 2013 12:03 PM
      To: VanDeGraaffGenerator@yahoogroups.com
      Subject: Re: [VanDeGraaffGenerator] resistors value

      Hi Doug,

      No problem - here's a PDF of the low pass filter circuit:
      http://www.capturedlightning.com/PDF/HV_Low_Pass_Filter.pdf

      Bert

      DOUG wrote:
      >
      >
      > Hi Bert; Sorry for my ignorance, but I don't know how to do the
      > (fixed font) thing.
      >
      > Doug
      >
      > ------------------------------------------------------------------------
      >
      > *From:*VanDeGraaffGenerator@yahoogroups.com
      > [mailto:VanDeGraaffGenerator@yahoogroups.com] *On Behalf Of *Bert
      > Hickman *Sent:* Monday, May 06, 2013 12:42 PM *T**o:*
      > VanDeGraaffGenerator@yahoogroups.com *Subject:* Re:
      > [VanDeGraaffGenerator] resistors value
      >
      > Hi Doug,
      >
      > Sounds great! Marx generators are notorious for blowing up charging
      > supplies via back-fed transients through the HV lines and via ground
      > bounce :^)
      >
      > You can mitigate these problems by connecting a HV low-pass filter
      > between your HV source and the input of the Marx generator. I'd
      > recommend using the following RC circuit which will prevent both
      > types of transients from nuking your HV supply. Use a fixed font
      > (Courier) to display properly.
      >
      > R1 R1 <----/\/\/\/\----o-----/\/\/\/\------> | o--/\/\/\/\-- To | R2
      > | To HV ----- | Marx Supply ----- | input | | o------------ |
      > <----/\/\/\/\----o-----/\/\/\/\------> R1 R1
      >
      > The R1 resistor values are not critical, but they should all be
      > identical - anything above 100k will work. R2 is a bleeder, so it
      > should be in the 500 - 1000 Meg range to limit power dissipation.
      > Each resistor must be capable of handling transients at least as high
      > as your maximum supply voltage (25 kV in your case). The capacitor
      > can be a simple 30 - 40 kV ceramic doorknob cap in the 500 - 2000 pF
      > range.
      >
      > Be careful not to operate your Marx generator near any solid state
      > equipment, network wiring, computers, scopes, etc., since the EMP
      > can easily trash these devices.
      >
      > Good luck and play safely!
      >
      > Bert -- Bert Hickman Stoneridge Engineering
      > http://www.capturedlightning.com
      > ***********************************************************************
      >
      >
      World's source for "Captured Lightning" Lichtenberg Figure sculptures,
      > magnetically "shrunken" coins, and scarce/out of print technical
      > books
      > ***********************************************************************
      >
      > DOUG wrote:
      >>
      >>
      >> Thanks Bert; I do have a source for the VR68 1 watt 200K ohm
      >> resistors @.25 cents each so that sounds really good to me.
      >>
      >> Do you think I will need anything between my power supply and the
      >> first stage of the Marx?
      >>
      >> Doug
      >>
      >> ----------------------------------------------------------
      >>
      >> *From:*VanDeGraaffGenerator@yahoogroups.com
      > <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
      >> [mailto:VanDeGraaffGenerator@yahoogroups.com
      > <mailto:VanDeGraaffGenerator%40yahoogroups.com>] *On Behalf Of *Bert
      >> Hickman *Sent:* Monday, May 06, 2013 1:21 AM *T**o:*
      >> VanDeGraaffGenerator@yahoogroups.com
      > <mailto:VanDeGraaffGenerator%40yahoogroups.com> *Subject:* Re:
      >> [VanDeGraaffGenerator] resistors value
      >>
      >> Hi Doug,
      >>
      >> A couple of alternatives would be VR68 or HVR68 1 watt HV metal
      >> film or ceramic resistors.These can handle 10 kV pulses, so you'll
      >> need to use at least two, and preferably three, resistors in series
      >> per stage. In your Marx application, the resistance value is not
      >> very critical since your stage capacitance is relatively small.To
      >> limit peak power stresses, use 100k - 200kohm resistors. You may
      >> also find something similar at a better price via eBay or through
      >> other electronic surplus vendors.
      >>
      >> Bert
      >>
      >> DOUG wrote:
      >>>
      >>>
      >>> Hi Bert;Thank you for your reply. I will be charging with a 25KV
      >>> power supply. Can you suggest something other than the 1 or 2
      >>> watt resisters?
      >>>
      >>> Douglas Johnson
      >>>
      >>> ----------------------------------------------------------
      >>>
      >>> *From:*VanDeGraaffGenerator@yahoogroups.com
      > <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
      >> <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
      >>> [mailto:VanDeGraaffGenerator@yahoogroups.com
      > <mailto:VanDeGraaffGenerator%40yahoogroups.com>
      >> <mailto:VanDeGraaffGenerator%40yahoogroups.com>] *On Behalf Of
      >> *Bert Hickman
      >>> *Sent:* Sunday, May 05, 2013 12:10 AM *T**o:*
      >>> VanDeGraaffGenerator@yahoogroups.com
      > <mailto:VanDeGraaffGenerator%40yahoogroups.com>
      >> <mailto:VanDeGraaffGenerator%40yahoogroups.com>
      >>> *Subject:* Re: [VanDeGraaffGenerator] resistors value
      >>>
      >>> HiDouglas,
      >>>
      >>> There is little difference in the voltage breakdown rating for
      >>> 1W and 2W carbon composite resistors. Your resistors must be able
      >>> to withstand the transient discharge voltage (i.e., the DC
      >>> charging voltage per resistor) when the Marx fires. If they flash
      >>> over, you'll dramatically decrease the output of your Marx
      >>> generator and any internal flashovers may cause the affected
      >>> resistor to explode or permanently change resistance value.
      >>>
      >>> For short (<10 uSec) pulse duty such as your Marx generator, a 1
      >>> or 2 watt carbon composition resistor can repetitively handle a
      >>> maximum of ~5-6 kV between terminals. So, if you plan to charge
      >>> your capacitors to 30 kV per stage, you'll need to use five-six
      >>> identical resistors in series (for each stage) to share the
      >>> voltage stress.
      >>>
      >>> Bert -- Bert Hickman Stoneridge Engineering
      >>> http://www.capturedlightning.com
      >>> ***********************************************************************
      >>>
      >>>
      >
      >>>
      World's source for "Captured Lightning" Lichtenberg Figure sculptures,
      >>> magnetically "shrunken" coins, and scarce/out of print
      >>> technical books
      >>> ***********************************************************************
      >>>
      >>>
      >>>
      >
      >>>
      drj11642 wrote:
      >>>> Here is my dilemma today, I need a bunch of 2 watt solid
      >>>> carbon resistors which are almost impossible to find, and when
      >>>> they can be found they are very expensive. On the other hand I
      >>>> have lots of 240ohms 1 watt solid carbon resistors. What would
      >>>> the resulting value be with 2 of these 1 watt resistors in
      >>>> series?
      >>>>
      >>>> My project that I need these for is a Marx generator using
      >>>> 30kv-1000pf ceramic disc caps.
      >>>>
      >>>> Thanks in advance to any response to my queries.
      >>>>
      >>>> Douglas Johnson
      >>>>
      >>>>
      >>>>
      >>>>
      >>>> ------------------------------------
      >>>>
      >>>> Yahoo! Groups Links
      >>>>
      >>>>
      >>>>
      >>>>
      >>>>
      >>>
      >>>
      >>>
      >>>
      >>
      >> -- Bert Hickman Stoneridge Engineering
      >> http://www.capturedlightning.com
      >> ***********************************************************************
      >>
      >>
      >
      >>
      World's source for "Captured Lightning" Lichtenberg Figure sculptures,
      >> magnetically "shrunken" coins, and scarce/out of print technical
      >> books
      >> ***********************************************************************
      >>
      >>
      >>
      >>
      >>
      >
      >>
      >
      >
      >



      ------------------------------------

      Yahoo! Groups Links
    • Bert Hickman
      Hi Doug, Yes. Bert ... *From:*VanDeGraaffGenerator@yahoogroups.com ... World s source for Captured Lightning Lichtenberg Figure sculptures, ... World s
      Message 2 of 15 , May 7, 2013
      • 0 Attachment
        Hi Doug,

        Yes.

        Bert

        DOUG wrote:
        > Hi Again Bert; will 3 of the 1 watt 200 ohm VR68's work for R2?
        >
        > -----Original Message----- From:
        > VanDeGraaffGenerator@yahoogroups.com
        > [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Bert
        > Hickman Sent: Tuesday, May 07, 2013 12:03 PM To:
        > VanDeGraaffGenerator@yahoogroups.com Subject: Re:
        > [VanDeGraaffGenerator] resistors value
        >
        > Hi Doug,
        >
        > No problem - here's a PDF of the low pass filter circuit:
        > http://www.capturedlightning.com/PDF/HV_Low_Pass_Filter.pdf
        >
        > Bert
        >
        > DOUG wrote:
        >>
        >>
        >> Hi Bert; Sorry for my ignorance, but I don't know how to do the
        >> (fixed font) thing.
        >>
        >> Doug
        >>
        >> ------------------------------------------------------------------------
        >>
        >>
        >>
        *From:*VanDeGraaffGenerator@yahoogroups.com
        >> [mailto:VanDeGraaffGenerator@yahoogroups.com] *On Behalf Of *Bert
        >> Hickman *Sent:* Monday, May 06, 2013 12:42 PM *T**o:*
        >> VanDeGraaffGenerator@yahoogroups.com *Subject:* Re:
        >> [VanDeGraaffGenerator] resistors value
        >>
        >> Hi Doug,
        >>
        >> Sounds great! Marx generators are notorious for blowing up
        >> charging supplies via back-fed transients through the HV lines and
        >> via ground bounce :^)
        >>
        >> You can mitigate these problems by connecting a HV low-pass filter
        >> between your HV source and the input of the Marx generator. I'd
        >> recommend using the following RC circuit which will prevent both
        >> types of transients from nuking your HV supply. Use a fixed font
        >> (Courier) to display properly.
        >>
        >> R1 R1 <----/\/\/\/\----o-----/\/\/\/\------> | o--/\/\/\/\-- To |
        >> R2 | To HV ----- | Marx Supply ----- | input | | o------------ |
        >> <----/\/\/\/\----o-----/\/\/\/\------> R1 R1
        >>
        >> The R1 resistor values are not critical, but they should all be
        >> identical - anything above 100k will work. R2 is a bleeder, so it
        >> should be in the 500 - 1000 Meg range to limit power dissipation.
        >> Each resistor must be capable of handling transients at least as
        >> high as your maximum supply voltage (25 kV in your case). The
        >> capacitor can be a simple 30 - 40 kV ceramic doorknob cap in the
        >> 500 - 2000 pF range.
        >>
        >> Be careful not to operate your Marx generator near any solid state
        >> equipment, network wiring, computers, scopes, etc., since the EMP
        >> can easily trash these devices.
        >>
        >> Good luck and play safely!
        >>
        >> Bert -- Bert Hickman Stoneridge Engineering
        >> http://www.capturedlightning.com
        >> ***********************************************************************
        >>
        >>
        >
        >>
        World's source for "Captured Lightning" Lichtenberg Figure sculptures,
        >> magnetically "shrunken" coins, and scarce/out of print technical
        >> books
        >> ***********************************************************************
        >>
        >>
        >>
        DOUG wrote:
        >>>
        >>>
        >>> Thanks Bert; I do have a source for the VR68 1 watt 200K ohm
        >>> resistors @.25 cents each so that sounds really good to me.
        >>>
        >>> Do you think I will need anything between my power supply and
        >>> the first stage of the Marx?
        >>>
        >>> Doug
        >>>
        >>> ----------------------------------------------------------
        >>>
        >>> *From:*VanDeGraaffGenerator@yahoogroups.com
        >> <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
        >>> [mailto:VanDeGraaffGenerator@yahoogroups.com
        >> <mailto:VanDeGraaffGenerator%40yahoogroups.com>] *On Behalf Of
        >> *Bert
        >>> Hickman *Sent:* Monday, May 06, 2013 1:21 AM *T**o:*
        >>> VanDeGraaffGenerator@yahoogroups.com
        >> <mailto:VanDeGraaffGenerator%40yahoogroups.com> *Subject:* Re:
        >>> [VanDeGraaffGenerator] resistors value
        >>>
        >>> Hi Doug,
        >>>
        >>> A couple of alternatives would be VR68 or HVR68 1 watt HV metal
        >>> film or ceramic resistors.These can handle 10 kV pulses, so
        >>> you'll need to use at least two, and preferably three, resistors
        >>> in series per stage. In your Marx application, the resistance
        >>> value is not very critical since your stage capacitance is
        >>> relatively small.To limit peak power stresses, use 100k - 200kohm
        >>> resistors. You may also find something similar at a better price
        >>> via eBay or through other electronic surplus vendors.
        >>>
        >>> Bert
        >>>
        >>> DOUG wrote:
        >>>>
        >>>>
        >>>> Hi Bert;Thank you for your reply. I will be charging with a
        >>>> 25KV power supply. Can you suggest something other than the 1
        >>>> or 2 watt resisters?
        >>>>
        >>>> Douglas Johnson
        >>>>
        >>>> ----------------------------------------------------------
        >>>>
        >>>> *From:*VanDeGraaffGenerator@yahoogroups.com
        >> <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
        >>> <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
        >>>> [mailto:VanDeGraaffGenerator@yahoogroups.com
        >> <mailto:VanDeGraaffGenerator%40yahoogroups.com>
        >>> <mailto:VanDeGraaffGenerator%40yahoogroups.com>] *On Behalf Of
        >>> *Bert Hickman
        >>>> *Sent:* Sunday, May 05, 2013 12:10 AM *T**o:*
        >>>> VanDeGraaffGenerator@yahoogroups.com
        >> <mailto:VanDeGraaffGenerator%40yahoogroups.com>
        >>> <mailto:VanDeGraaffGenerator%40yahoogroups.com>
        >>>> *Subject:* Re: [VanDeGraaffGenerator] resistors value
        >>>>
        >>>> HiDouglas,
        >>>>
        >>>> There is little difference in the voltage breakdown rating for
        >>>> 1W and 2W carbon composite resistors. Your resistors must be
        >>>> able to withstand the transient discharge voltage (i.e., the
        >>>> DC charging voltage per resistor) when the Marx fires. If they
        >>>> flash over, you'll dramatically decrease the output of your
        >>>> Marx generator and any internal flashovers may cause the
        >>>> affected resistor to explode or permanently change resistance
        >>>> value.
        >>>>
        >>>> For short (<10 uSec) pulse duty such as your Marx generator, a
        >>>> 1 or 2 watt carbon composition resistor can repetitively handle
        >>>> a maximum of ~5-6 kV between terminals. So, if you plan to
        >>>> charge your capacitors to 30 kV per stage, you'll need to use
        >>>> five-six identical resistors in series (for each stage) to
        >>>> share the voltage stress.
        >>>>
        >>>> Bert -- Bert Hickman Stoneridge Engineering
        >>>> http://www.capturedlightning.com
        >>>> ***********************************************************************
        >>>>
        >>>>
        >>
        >>>>
        >
        >>>>
        World's source for "Captured Lightning" Lichtenberg Figure sculptures,
        >>>> magnetically "shrunken" coins, and scarce/out of print
        >>>> technical books
        >>>> ***********************************************************************
        >>>>
        >>>>
        >>>>
        >>
        >>>>
        >
        >>>>
        drj11642 wrote:
        >>>>> Here is my dilemma today, I need a bunch of 2 watt solid
        >>>>> carbon resistors which are almost impossible to find, and
        >>>>> when they can be found they are very expensive. On the other
        >>>>> hand I have lots of 240ohms 1 watt solid carbon resistors.
        >>>>> What would the resulting value be with 2 of these 1 watt
        >>>>> resistors in series?
        >>>>>
        >>>>> My project that I need these for is a Marx generator using
        >>>>> 30kv-1000pf ceramic disc caps.
        >>>>>
        >>>>> Thanks in advance to any response to my queries.
        >>>>>
        >>>>> Douglas Johnson
        >>>>>
        >>>>>
        >>>>>
        >>>>>
        >>>>> ------------------------------------
        >>>>>
        >>>>> Yahoo! Groups Links
        >>>>>
        >>>>>
        >>>>>
        >>>>>
        >>>>>
        >>>>
        >>>>
        >>>>
        >>>>
        >>>
        >>> -- Bert Hickman Stoneridge Engineering
        >>> http://www.capturedlightning.com
        >>> ***********************************************************************
        >>>
        >>>
        >>
        >>>
        >
        >>>
        World's source for "Captured Lightning" Lichtenberg Figure sculptures,
        >>> magnetically "shrunken" coins, and scarce/out of print technical
        >>> books
        >>> ***********************************************************************
        >>>
        >>>
        >>>
        >>>
        >>>
        >>
        >>>
        >>
        >>
        >>
        >
        >>>
        >
        >
        > ------------------------------------
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
        > ------------------------------------
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
      • DOUG
        Hi Bert; Thank you again and thanks also to all the other members who responded to my questions regarding the build of a Marx Generator. All components are
        Message 3 of 15 , May 9, 2013
        • 0 Attachment
          Hi Bert; Thank you again and thanks also to all the other members who
          responded to my questions regarding the build of a Marx Generator.
          All components are ordered and on their way, so I will soon be soldering
          away!
          It is great to find people such as yourselves that can find time to respond
          to a, non-technical, person with a hobby quite over his head. LOL
          Thanks again to all;
          Douglas Johnson

          -----Original Message-----
          From: VanDeGraaffGenerator@yahoogroups.com
          [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Bert Hickman
          Sent: Tuesday, May 07, 2013 12:03 PM
          To: VanDeGraaffGenerator@yahoogroups.com
          Subject: Re: [VanDeGraaffGenerator] resistors value

          Hi Doug,

          No problem - here's a PDF of the low pass filter circuit:
          http://www.capturedlightning.com/PDF/HV_Low_Pass_Filter.pdf

          Bert

          DOUG wrote:
          >
          >
          > Hi Bert; Sorry for my ignorance, but I don't know how to do the
          > (fixed font) thing.
          >
          > Doug
          >
          > ------------------------------------------------------------------------
          >
          > *From:*VanDeGraaffGenerator@yahoogroups.com
          > [mailto:VanDeGraaffGenerator@yahoogroups.com] *On Behalf Of *Bert
          > Hickman *Sent:* Monday, May 06, 2013 12:42 PM *T**o:*
          > VanDeGraaffGenerator@yahoogroups.com *Subject:* Re:
          > [VanDeGraaffGenerator] resistors value
          >
          > Hi Doug,
          >
          > Sounds great! Marx generators are notorious for blowing up charging
          > supplies via back-fed transients through the HV lines and via ground
          > bounce :^)
          >
          > You can mitigate these problems by connecting a HV low-pass filter
          > between your HV source and the input of the Marx generator. I'd
          > recommend using the following RC circuit which will prevent both
          > types of transients from nuking your HV supply. Use a fixed font
          > (Courier) to display properly.
          >
          > R1 R1 <----/\/\/\/\----o-----/\/\/\/\------> | o--/\/\/\/\-- To | R2
          > | To HV ----- | Marx Supply ----- | input | | o------------ |
          > <----/\/\/\/\----o-----/\/\/\/\------> R1 R1
          >
          > The R1 resistor values are not critical, but they should all be
          > identical - anything above 100k will work. R2 is a bleeder, so it
          > should be in the 500 - 1000 Meg range to limit power dissipation.
          > Each resistor must be capable of handling transients at least as high
          > as your maximum supply voltage (25 kV in your case). The capacitor
          > can be a simple 30 - 40 kV ceramic doorknob cap in the 500 - 2000 pF
          > range.
          >
          > Be careful not to operate your Marx generator near any solid state
          > equipment, network wiring, computers, scopes, etc., since the EMP
          > can easily trash these devices.
          >
          > Good luck and play safely!
          >
          > Bert -- Bert Hickman Stoneridge Engineering
          > http://www.capturedlightning.com
          > ***********************************************************************
          >
          >
          World's source for "Captured Lightning" Lichtenberg Figure sculptures,
          > magnetically "shrunken" coins, and scarce/out of print technical
          > books
          > ***********************************************************************
          >
          > DOUG wrote:
          >>
          >>
          >> Thanks Bert; I do have a source for the VR68 1 watt 200K ohm
          >> resistors @.25 cents each so that sounds really good to me.
          >>
          >> Do you think I will need anything between my power supply and the
          >> first stage of the Marx?
          >>
          >> Doug
          >>
          >> ----------------------------------------------------------
          >>
          >> *From:*VanDeGraaffGenerator@yahoogroups.com
          > <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
          >> [mailto:VanDeGraaffGenerator@yahoogroups.com
          > <mailto:VanDeGraaffGenerator%40yahoogroups.com>] *On Behalf Of *Bert
          >> Hickman *Sent:* Monday, May 06, 2013 1:21 AM *T**o:*
          >> VanDeGraaffGenerator@yahoogroups.com
          > <mailto:VanDeGraaffGenerator%40yahoogroups.com> *Subject:* Re:
          >> [VanDeGraaffGenerator] resistors value
          >>
          >> Hi Doug,
          >>
          >> A couple of alternatives would be VR68 or HVR68 1 watt HV metal
          >> film or ceramic resistors.These can handle 10 kV pulses, so you'll
          >> need to use at least two, and preferably three, resistors in series
          >> per stage. In your Marx application, the resistance value is not
          >> very critical since your stage capacitance is relatively small.To
          >> limit peak power stresses, use 100k - 200kohm resistors. You may
          >> also find something similar at a better price via eBay or through
          >> other electronic surplus vendors.
          >>
          >> Bert
          >>
          >> DOUG wrote:
          >>>
          >>>
          >>> Hi Bert;Thank you for your reply. I will be charging with a 25KV
          >>> power supply. Can you suggest something other than the 1 or 2
          >>> watt resisters?
          >>>
          >>> Douglas Johnson
          >>>
          >>> ----------------------------------------------------------
          >>>
          >>> *From:*VanDeGraaffGenerator@yahoogroups.com
          > <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
          >> <mailto:%2AVanDeGraaffGenerator%40yahoogroups.com>
          >>> [mailto:VanDeGraaffGenerator@yahoogroups.com
          > <mailto:VanDeGraaffGenerator%40yahoogroups.com>
          >> <mailto:VanDeGraaffGenerator%40yahoogroups.com>] *On Behalf Of
          >> *Bert Hickman
          >>> *Sent:* Sunday, May 05, 2013 12:10 AM *T**o:*
          >>> VanDeGraaffGenerator@yahoogroups.com
          > <mailto:VanDeGraaffGenerator%40yahoogroups.com>
          >> <mailto:VanDeGraaffGenerator%40yahoogroups.com>
          >>> *Subject:* Re: [VanDeGraaffGenerator] resistors value
          >>>
          >>> HiDouglas,
          >>>
          >>> There is little difference in the voltage breakdown rating for
          >>> 1W and 2W carbon composite resistors. Your resistors must be able
          >>> to withstand the transient discharge voltage (i.e., the DC
          >>> charging voltage per resistor) when the Marx fires. If they flash
          >>> over, you'll dramatically decrease the output of your Marx
          >>> generator and any internal flashovers may cause the affected
          >>> resistor to explode or permanently change resistance value.
          >>>
          >>> For short (<10 uSec) pulse duty such as your Marx generator, a 1
          >>> or 2 watt carbon composition resistor can repetitively handle a
          >>> maximum of ~5-6 kV between terminals. So, if you plan to charge
          >>> your capacitors to 30 kV per stage, you'll need to use five-six
          >>> identical resistors in series (for each stage) to share the
          >>> voltage stress.
          >>>
          >>> Bert -- Bert Hickman Stoneridge Engineering
          >>> http://www.capturedlightning.com
          >>> ***********************************************************************
          >>>
          >>>
          >
          >>>
          World's source for "Captured Lightning" Lichtenberg Figure sculptures,
          >>> magnetically "shrunken" coins, and scarce/out of print
          >>> technical books
          >>> ***********************************************************************
          >>>
          >>>
          >>>
          >
          >>>
          drj11642 wrote:
          >>>> Here is my dilemma today, I need a bunch of 2 watt solid
          >>>> carbon resistors which are almost impossible to find, and when
          >>>> they can be found they are very expensive. On the other hand I
          >>>> have lots of 240ohms 1 watt solid carbon resistors. What would
          >>>> the resulting value be with 2 of these 1 watt resistors in
          >>>> series?
          >>>>
          >>>> My project that I need these for is a Marx generator using
          >>>> 30kv-1000pf ceramic disc caps.
          >>>>
          >>>> Thanks in advance to any response to my queries.
          >>>>
          >>>> Douglas Johnson
          >>>>
          >>>>
          >>>>
          >>>>
          >>>> ------------------------------------
          >>>>
          >>>> Yahoo! Groups Links
          >>>>
          >>>>
          >>>>
          >>>>
          >>>>
          >>>
          >>>
          >>>
          >>>
          >>
          >> -- Bert Hickman Stoneridge Engineering
          >> http://www.capturedlightning.com
          >> ***********************************************************************
          >>
          >>
          >
          >>
          World's source for "Captured Lightning" Lichtenberg Figure sculptures,
          >> magnetically "shrunken" coins, and scarce/out of print technical
          >> books
          >> ***********************************************************************
          >>
          >>
          >>
          >>
          >>
          >
          >>
          >
          >
          >



          ------------------------------------

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