[Amps] Resonant chokes

[Carl]

----- Original Message ----- 
From: "Bob" <bobt at iafrica.com>
To: <Amps at contesting.com>
Sent: Saturday, December 22, 2012 12:44 PM
Subject: [Amps] Resonant chokes


> Hi guys,
>              I went through the measurement of DC chokes awhile back on
> this forum. Any measurements you make with AC doesn't mean much unless 
> there
> is some DC involved. There is only one practical method of doing this that 
> I
> know of( the other requires a test choke ~ X10 times the size of the choke
> that you want to test). I went through this in some detail (search ZS6BXI
> and DC choke). To do the test you need a big source of stored energy (big
> cap bank) or a big battery/supply. Basically you connect the choke across 
> a
> DC supply (usually with a thyristor) and measure the current rise with a
> digital storage scope, the slope of the curve gives you the dI/dT at the
> point you are interested in and another probe the voltage across the choke
> at the same point then you use L = E dI/dT.
>
> Regards Bob ZS6BXI


How did Henry and others long before them do it before all that fancy stuff 
became available?

Carl
KM1H