Ken Layton wrote in message
...
Copper oxide was used for years in movie theaters as rectifiers for
the exciter lamp power supplies in the soundheads.



The second to last page of the 1933 Westinghouse book refers to 2 units
pictured being used in ""talkie" installations" , but nowhere in the book is
there reference to either CuO or Se, just metal rectifiers.


--
Diverse Devices, Southampton, England
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