Re: Circuit Symbol

Ralph Mowery wrote:

cd@notformail.com says...

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Gentlemen,
>
A chum of mine who's into classic cars has asked me to take a look at
the radio out of his 1938 Bentley which has never worked in all the
years he's had it in his ownership. Obviously, given the year, this is
an all-valve job (if you're in the US, I'm referring to what YOU call
"tubes"). There isn't a single semiconductor in this thing cos they
weren't invented until much later. The valves require an anode
("plate" if you're in the US) voltage of 235V so there's a DC to DC
up-converter to generate that from the 12V battery. Rather interesting
approach they've used and one can see an embryonic SMPS in there!
Anyway, there's a schematic symbol I can't identify for sure. Could be
a fuse, could be a link or jumper, could be a current test point, I've
no idea. So can some kind, intelligent soul enlighten me? They're
labeled V1 through V8. Here's a pic:
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https://disk.yandex.com/i/mIv_txLia6Xx4Q
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>

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They are the filiments (heaters) for the tubes (valves).  It is very
common for the tube circuits to put all the filiments in one area of the
schematic.  It makes it simpler to look at when they are all in a series
or parallel circuit.  The numbers at them are the pin nubers of the
tubes.  As  there are 8 tubes in the radio they will be labled V1 to V8
with the V standing for the  Valve they are in.

FWIW, the ARRL equivalent is shown in the uppermost-rightmost corner on
this schematic symbol sheet:

<http://arrl.org/files/file/General%20Class%20License%20Manual/SYMBOLSMM.pdf>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.