[Fwd: Re: Power Supply for Crookes/Geissler Tubes (fwd)] (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Tue, 20 Nov 2007 15:35:49 -0800
From: Ed Phillips <evp@xxxxxxxxxxx>
To: "hvlist@xxxxxxxxxx" <hvlist@xxxxxxxxxx>
Subject: [Fwd: Re: Power Supply for Crookes/Geissler Tubes (fwd)]

Trying again - bounced first time.

-------- Original Message --------
Subject: 	Re: Power Supply for Crookes/Geissler Tubes (fwd)
Date: 	Tue, 20 Nov 2007 12:21:49 -0800
From: 	Ed Phillips <evp@xxxxxxxxxxx>
Reply-To: 	evp@xxxxxxxxxxx
To: 	High Voltage list <hvlist@xxxxxxxxxx>
References: 	<Pine.LNX.4.10.10711192001350.14652-100000@xxxxxxxxxxxxxxxx>



High Voltage list wrote:

>Original poster: Steven Roys <sroys@xxxxxxxxxx>
>
>
>
>---------- Forwarded message ----------
>Date: Sun, 18 Nov 2007 18:44:02 -0800 (PST)
>From: C. Sibley <a37chevy@xxxxxxxxx>
>To: High Voltage list <hvlist@xxxxxxxxxx>
>Subject: Power Supply for Crookes/Geissler Tubes
>
>I've recently come into possesion of some Crookes and Giessler tubes.  Can anyone suggest a good (and simple) power supply to run these things? 
>
>Would an automotive spark coil/light dimmer setup be appropriate?
>
>Thanks,
>
>Curt.
>
   Such setups work fine but I would suggest starting with a small 
series capacitor [say 0.25 ufd or so] as, depending on the particular 
coil, you may get enough output to damage the tube.  However, the output 
voltage consists of spikes of alternating polarity which mixes up 
polarity effects in the tube.  If you'll use a DC powered coil [typical 
transistor switch or the like] you'll get much closer to unipolar pulses 
and will probably get more interesting discharges.  The light dimmer 
circuit is quick and easy but I prefer the DC drive.  I have a schematic 
for a fairly simple Quadrac driver which I'd be glad to send and there 
are plenty of sources on line for the transistor/IGBT switching driver.

Ed