Re: DSL-Diode Spark Gap Logic

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Barry,

At 03:37 PM 10/3/2002 -0400, you wrote:
>Hi All,
>    I am about 1463 e-mails behind at the moment.  Classwork will limit my 
>reading until December.  In the mean time, I had a free 30 minutes for 
>experimentation.  I tried the following:
>
>1. Transformer is 4 kV, 30 MA bug zapper transformer.  Transformer HV output 
>is connected to the tank capacitor via 5 KOhm-50 Watt resistor plus two 6 kV 
>diodes (All Electronics) in series (12 kV total).
>2. 0.01 uF MMC.
>3. Resonant frequency-50 kHz.
>4. Primary and secondary are from an ancient Spellman HVPS.
>5. Secondary is pie wound-10 pies-4 inches winding length.
>6. Victoreen-DSL-SGCA-2500D precision spark gap (fires at 2500 Volts within 
>5 %-Haven't found another source) paralleled with 8 series connected diodes 
>(1N5408-1kV-400 Ampere surge-All Electronics, Digikey).

I have about 75 of the Victoreen spark gaps here.  I may have bought the
last of them ;-)  $1 each plus shipping ;-)

>
>Notes:  Fired the coil for 1 minute.  Unpluged it and then shorted out the 
>MMC.  Touched the SGCA-2500D and diodes.  They were both barely perceptable 
>warm.  Under normal operation the SGCA-2500D would be too hot to touch after 
>30 seconds.

That is very interesting!!  I wonder if the diode is going into some weird
conduction state once it is fired.  Almost like an SCR.  It is just
"sticking one" or something like that.  I would guess the streamer power is
better too if the gap is not heating much.

>
>Theory:  The SGCA-2500D conducts for only 1/2 cycle.  The diode string 
>conducts for the other half cycle (extrapolation from Terry's research).

That would only cut the heat in 1/2 normally.

>
>Comments: It is interesting that such a low frequency diode works at 50 kHz. 
> More experiments at higher power as time permits.  Interesting 
>possibilities here.

Maybe the diode is doing something really cool in this case!!  I am not
sure I have the stuff here to reproduce this but I'll look.

Cheers,

	Terry


>
>Cheers,
>Barry
>