[GreenKeys] Loop power supplies

[drlegendre .]

Duh, current meter.. it has a low-Z (and low-R) shunt across the terminals.
No, it's of no consequence.

On Sun, Mar 4, 2018 at 10:41 PM, drlegendre . <drlegendre at gmail.com> wrote:

> @Jeff
>
> Ok.. so by using a tube as the pass element, they're eliminating the
> inductive rise time of the high-value rheostat(s) which would otherwise be
> in series with the output current. Is this the whole reason for using this
> supply?
>
> What then about the inductance of the meter winding? Of no consequence?
>
> On Sun, Mar 4, 2018 at 9:28 PM, Jeffrey Angus <jdangus at att.net> wrote:
>
>> On 3/4/18 9:01 PM, drlegendre . wrote:
>>
>>> IOW it's not a constant-current supply, but rather a high
>>> voltage (~300V) current-adjustable supply.
>>>
>> That is correct.
>>
>>> Ultimately, its behavior isn't much different than that of a
>>> simple passive rheostat - nor am I exactly sure what advantage
>>> it provides over the former.
>>>
>> Actually there is.
>> This difference is small, but using a vacuum tube as a variable
>> resistor allows the rise time of the current through the selector
>> magnet rise a little bit faster.
>>
>>
>>
>>
>>
>> --
>> "I am a river to my people."
>> Jeff-1.0
>> WA6FWI
>> www.foxsmercantile.com
>>
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