Correct -- it supplied the "B+ voltage' used for the plate and screen
circuits

Comedian Steven Wright has this question as part of his humor

--
Keyboard to you


"Michael Black" wrote in message
...

"Keyboard In The Wilderness" ) writes:
Correct -- but for For what purpose ??


To supply the B+. That's a giveaway.

Michael

--
Keyboard to you


"dxAce" wrote in message
...


Keyboard In The Wilderness wrote:

Hey I can buy A batteries, (AA, and AAA), and C batteries -- right
What happened to the B battery ???

There were 'B' batteries used in the old sets.

dxAce
Michigan
USA