Plate impedance varies so much with drive, supply voltage etc. That is why
we have knobs.
I remember in my younger days, did not worry so much about what it actually was
but tapped
the tank coil where it worked best and seemed to have a good Q (selectivity).
But those were the old days. Now it seems that folks want an exact answer for
something
that is not so exact.
One day I needed to quickly build a simple plasma generator source for a
Physics demo.
I got a reasonably gaped variable capacitor from the junk supply and would a
coil with some
#12 wire. We had some 13.56 packed crystal oscillators and I simply ran it thru
a CMOS buffer
and into the gate of a IRF520 FET. The drain simply went to a single loop at
the ground end
of the coil and to +supply, bypassed naturally.
Had a small fluorescent bulb handy and lit it right up. My associate engineer
was quite amazed that
I had not made any calculations and that the single loop of wire worked. In his
mind the few inches of
wire in the link coupling was a short. I then needed a tuning indicator and
got a NE-2 from old stock
and soldered the two leads together and then the hot side of the tuned circuit.
Again, my associate
did not understand how that worked either. I just told the professor to tune
the capacitor for max
glow of the NE-2 and he was ready to demonstrate the device. We had a partly
evacuated sealed
glass tube, and the small fluorescent bulb to demonstrate the device. They
could observe the
spectra produced by them with the simple hand held spectrometers. They were
simply of
cardboard tubes with a slit on one end and a piece of a CD as a grating. The
aluminum coating
was removed from the CD.
73
Bill wa4lav
________________________________________
From: Amps [amps-bounces@contesting.com] on behalf of Carl [km1h@jeremy.mv.com]
Sent: Sunday, February 16, 2014 4:08 PM
To: Ian Swain; Amps@contesting.com
Subject: Re: [Amps] Sb200 plate impedance
Under what conditions?
At 2400V at 500 ma it will be tween 2800-2900 Ohms depending on the several
formulas use.
I keep it simple and for a SSB linear divide the voltage by the current and
mulyiply by 1.7 which is a K factor based upon class of operation.
Carl
KM1H
----- Original Message -----
From: "Ian Swain" <insane.swain@gmail.com>
To: <Amps@contesting.com>
Sent: Sunday, February 16, 2014 3:14 PM
Subject: [Amps] Sb200 plate impedance
> Crazy simple question I know for most people on this mailing list.
>
> What's the plate impedance on the sb200 ?
>
> Regards ian de zl2ias
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
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