Grid Bias Cell. 1st Button-Battery!!!

[GlennSprigg]

Well I'll be Hornswaggled!!  (Look it up... hahaha)... Just when I thought I knew it all !!, (AS IF!), along came the bias-cell.
I just watched a tube-radio restoration of a 1937 Howard Radio, and it contained something I've never heard of before!!   
Negative grid-bias used to, (and later was again!), done using a combination of resistors and capacitors.  In 1936, inventor Samuel Ruben
designed the 1st miniature dry-cell to use for this purpose!!  (and on old battery powered tube radios, replaced the so-called 'C' battery)...

He did a lot of work with/for 'Mallory' at the time. Usually, (as per today's methods/standards), the main body/cup of the device was the
Anode, and the carbonized central inner disk on the other side was the Cathode!. (Today, the main-body is also +ve!!).  They came in two
styles, 1-v and 1.25-v, though the 1-v was by far the most common. They had spring-loaded mounting clips, as in the following pic...

Here's an Ad at the time, for their availability, and a typical cct diag showing their common representation...
   
Evidently, one old radio rejuvenator found a N.O.S. one that still measured .9-v after 50 years!!  In use, they literally drew no current, as
it was basically a Voltage presence to do the biasing.   Evidently, due to the degradation of the 'Connectors' themselves, and not the actual
batteries, they fell into disuse beyond WW-II. Samuel Ruben continued research that led to the development of miniature mercury batteries.

These were widely used by the U.S. Army during World War II in portable radios and mine detectors. After the war, Ruben continued to work
with Mallory to develop alkaline batteries. The Duracell brand of batteries was introduced in 1964. Today, Duracell is a div of The Gillette Co.   

[Alex Eisenhut]

Never heard of that battery. Pretty cool.