"John Byrns" <byrnsj@[EMAIL PROTECTED]
> wrote in message
news:byrnsj-7E6938.11355723042008@[EMAIL PROTECTED]
> In article <480F45FF.BADC96DF@[EMAIL PROTECTED]
>,
> Eeyore <rabbitsfriendsandrelations@[EMAIL PROTECTED]
> wrote:
>
>> John Byrns wrote:
>>
>> > Peter Wieck <pfjw@[EMAIL PROTECTED]
> wrote:
>> > > John Byrns <byr...@[EMAIL PROTECTED]
> wrote:
>> > >
>> > > > Correct, but the parallel connected lamps in your house are feed
>> > > > from
>> > > > what is essentially a constant voltage source, not a constant
>> > > > current
>> > > > source. If you house hold power was supplied by a constant
current
>> > > > source, each time you turned on another lamp the ones that were
>> > > > already
>> > > > on would get dimmer, and if you had only one lamp on it probably
>> > > > wouldn't last very long before burning out.
>> > >
>> > > Um - let's make sure I understand this correctly - current is
limited
>> > > by the fuse on each individual leg. *BUT* the amount of current
>> > > relative to the individual devices is unlimited, the fuse being the
>> > > actual controlling factor? That makes more sense - But if the
>> > > filament
>> > > winding is sufficiently robust (and it should be in a well-designed
>> > > transformer), would this not be essentially the same condition -
the
>> > > tube filament (heater) becoming the de-facto fuse?
>> >
>> > Peter, the point was that the lights in your house that you were
>> > talking
>> > about are feed from a voltage source, not a current source as is
being
>> > discussed in this (sub) thread.
>>
>> It seems to be your misunderstanding that a *current source* was what
was
>> being
>> considered.
>
> You are quite correct, I misinterpreted "current limited" to mean
> "current source", my mistake. My error resulted from Iain's statement
> "A current limiter for tube heaters. People are keen to use voltage
> regulation, which doesn't seem to me to be so important." Which lead me
> to think he was talking about using a current regulator to replace
> heater "voltage regulation" whose value he discounted.
>
>> My understanding was a regulated voltage with a *current limit* which
is
>> quite
>> different. The current limit might be set for say 110% of Inominal and
>> would
>> only kick in during the warm-up period.
>
> Well at least a "current limit" if you read Iain's original statement
> which didn't imply "voltage regulation".
>
>> In any case since both tubes would be receiving the same heater voltage
>> your
>> point is moot.
>
> I don't see how that follows unless it can be shown that the heater
> voltage would be within the specification for the tubes in question.
>
Hello John.. Because tubes heaters are happy +/- 5% and it is pretty
easy to get 6V3 spot on, I did not think the voltage regulation to
be too important. But current limiting would be much more useful to
me.
Regards
Iain
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