[Johnson] The Viking II

[Glen Zook]

Add up the current values of all the tubes.  Next
divide this by 10.  That will allow for the loss in
the transformer plus a safety margin.

To get the actual current drawn by the filament
transformer you divide this figure by 20.  That will
get you real close to the current into the transformer
(since most electric companies try to maintain about
125 volts to the house these days).  Then you have to
allow for the fact that a transformer is no where near
"perfect".  That is why I said to divide the current
requirements at 6.3 volts by 10.  This allows for the
actual current requirement of the transformer, the
fact that transformers are not 100% efficient, plus
about a 25% to 33% "extra" to allow for heater warm
up, and a bit of "slop" to keep from blowing the fuse
all the time.

The "20" figure comes from the fact that 6.3 goes into
125 almost exactly 20 times!  This is the "step down"
ratio between the input voltage and the output
voltage.

Glen, K9STH


--- KENNETH A CRIPS <w7itc@msn.com> wrote:

Any advice on how to figure out a value for this fuse.

=====
Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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