[Amps] plate choke

[Michael Tope]

----- Original Message ----- 
From: "Roy Koeppe" <royanjoy at ncn.net>
> 
> Follows is published data pertaining to Ohmite plate choke model Z-7,
> operating range 3 to 20 mHz, 84 uH, core dimensions 6" x 9/16"...
> 
>            "Rp (apparent parallel resistance) at 3 mHz -(brace
> yourself)- is appreciably in excess of 200,000 ohms".
> 
> I must assume that their 1.8 mHz model, if they made one, would have the
> same low-end specs.
> 
> I also agree that manufacturers do try to cram 160M into a single plate
> choke with high compromise. Still 3000 ohms is a far cry from 200,000.
> 

It suspect that they are talking about the Rp component as it relates
to the ohmic losses (read self-heating) of the choke. For Xp = 3000 ohms, 
Rp would be well in excess of 200,000 ohms even for a modest unloaded 
Q of 67. I am sure that is what they are talking about. At 200,000 ohms 
(resistive) and 1900V rms anode swing, that would be 18 watts dissipated 
in Rp. IOW, the equivalent circuit of the Z-7 choke would be something like
3000 ohms reactance in parallel with 200,000 ohms resistive, where the
200,000 ohms represents the parallel equivalent of the series resistance
in the choke windings. 

73 de Mike, W4EF......................