On 01/07/2011 06:50, RussellMc wrote:
> I would expect that the HT would be "best" addressed by using a
> battery that best suited Wh/$ considerations and adding an inverter.
> That is certainly the approach that I would personally choose as the
> "straw man" to measure other options against.
> These can be made to idle at full voltage with a mean consumption in
> the 10's of uA range.
> Even at say 100 uA you consume about 75 mAh in a month.
> With a little magic you can probably make a power pack with
> essentially zero off state current. eg HT turned on by filament load
> detect.
>
> A 1V filament would be amply served by a single NimH with a series
> regulator transistor (MOSFET best).
> Your desired 800 mA and 50 mV drop regulator load requires Rds +
> wiring<  ~ 60 milliOhm which is very easily achived with a MOSFET.
> You could use a buck converter but the efficiency gain is minimal.
>

All true for "normal" design criteria. But then why bother using valves=20
at all. Might as well use DDS, synth, RF ICs, IC audio amp...

If operation time between charges and weight was issue a laptop type=20
Li-ion pack with it's built in cell monitoring is likely the best way.=20
But if you want only transistor/ICs in the external charger, then the=20
battery packs ought to be dumb.

I toyed briefly with simply bulk buy of Alkaline and disposable packs

WS88 in early 1950s used disposable dry cell 1.5V+90V that exactly=20
fitted Ammunition pouch. the Radio same size.
http://www.rod.beavon.clara.net/ws88.htm
http://www.vmars.org.uk/ws88.html
(Battery pack not shown, it's same size as radio). The WS88 Radio uses=20
slightly inferior and slightly older B7G miniature valves. The Russian=20
Military sub-miniature valves are much smaller (10mm x 44mm or less) and=20
unusually are entirely made of rods for all electrodes except cathode=20
which is an oxide coated heater filament.

I briefly discussed Vibrator packs and Rotary Converter / Dynamotors=20
with my Vintage Radio friend. Since we don't have a Tank, the "rotary=20
converter" was only mentioned in passing. "Vibrator packs" are evil.=20
Basically a sp c/o relay designed as self oscillating transformer. I did=20
once have an audio P.A. with pair of EL34 that would run of mains or 12V=20
car bat. via vibrator pack.
--=20
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