[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: cockcroft vs. marxs



Original poster: "Shaun Epp by way of Terry Fritz <twftesla-at-qwest-dot-net>" <scepp-at-mts-dot-net>

a Marx generator charges all capacitors to ~ Vin through resistors, each cap
charging itself off of the previous capacitor, so they are slow charging as
a result of the series resistance and the number of stages.  Then the
ignition pulse at the first stage arcs over and series connects that
capacitor to the second stage, this higher voltage also ripples through all
spark gaps at the same time so that all caps are connected in series.  One
important note is that the spark gaps must be in line with eachother( UV
flash helps the other gaps fire) and in the air.

The cascade voltage multiplier are usually in oil or epoxy, or some other
insulation to reduce corona leakage.  They are used to power to anode of a
CRT in monitors and tv sets, this is usually a static charge (ie. low
currents). They use the minimum of parts, usually half wave rectified.   The
cw- cockcroft versions are full wave or centertapped rectified version of
the cascade multipliers and I have seen them used to xray/CT scanner power
supplies.  These have higher, continuous current capabilities and use alot
more parts (ie. more hv diodes and caps).  They achive the parallel charge
with hv diodes and series discharge through direct conection.  The pointer
to the previouly web site shows some good schematics of them both.  I'm not
to sure of the pros and cons yet.  Oh yeh, the cost of the diodes!!
Although I happen to have a box of them :-)

I hope this helps,

Shaun Epp,  Electronic Technologist


> Original poster: "Garry Freemyer by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <garry-at-ndfc-dot-com>
>
>
> Hmmm, what's the difference between a Cockroft multiplier and a Marx
> Generator?
>