DIYbanter - View Single Post - Door bell

Terry Casey

In article ,
says...

Bob Eager wrote:
On Sun, 22 Jan 2017 11:35:42 +0000, Dave Plowman (News) wrote:

I'm old enough to just remember valve radio mics. But
can't remember what batteries they used.

Probably used the B7G 'battery' valves (e.g. DF96). 1.4v filament and 90v
anode.

Or even the car radio ones which used 12 volt 'HT' as well as 12 volt
filaments.

Hardly. Those had either 6.3V 300mA or 12.6V 150mA heaters -
you would have needed a hefty battery (or accumulator) to
power those!

--

Terry