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RE: Tube Data

Are you sure?

At resonance the impedance of a parallel LC is infinite.
Surely the tube sees the corona load impedance transformed into the primary
tank.

Simon


-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, February 24, 2000 8:25 PM
To: tesla-at-pupman-dot-com
Subject: Re: Tube Data


Original Poster: "Megavolt Nick" <tesla-at-fieldfamily.prontoserve.co.uk> 

Hi All,
          One of the main characteristics of an electron emission device
like a vacuum tube is that it will have a comparatively high output
impedance. The tube I mention below can supply 400ma at 5kV -

Z = V/I

Z = 5000/0.4

Z = 12500

This means that to avoid damaging the tube the load connected to it must
have an impeadance of at least 12.5 kiloOhms.  Therefore it must use a
primary coil with a large inductance to provide this impedance.

For a typical disruptive TC operating at 300kHz with a 0.1µF primary
capacitor you would need about 28µH of primary inductance to tune, which has
an impedance of only 5 Ohms; whereas a vacuum tube design would use a much
larger primary to provide the large impedance, about 6.6mH would be needed.

This arrangement would suit a magnifier system as the large primary needed
could be wound co-axially with the secondary for most of its length giving
the very high K factor a magnifier needs.

Regards
Nick Field



> Original Poster: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz>
>
> Hi Nick (and others who have said such things in the past):
>
> > Original Poster: "Megavolt Nick" <tesla-at-fieldfamily.prontoserve.co.uk>
> >
> > Hi Guys,
> >              thanks for all your help.  I've eventually managed to get
the
> > data from an online database.  Its a 2250W transmitter tube.  The anode
> > dissipation is 500W, plate voltage 5kV, anode current 400mA.
> > I wonder if anyone has ever tried a tube driven magnifier?
> > To get the impeadance match right you'd need a large primary which would
> > suit the tight coupling of a magnifier driver.
>
> Could you expand on that last statement and perhaps throw some
> meaningful figures in for us to see please?
>
> Regards,
> Malcolm
>
>
>
>