Is this Kosher or am I just wanting believe in a perpetual motion genorator?

[Tony Alfrey]

Tony Alfrey wrote:
> James McDonald wrote:
>> http://www.devicepedia.com/news/betavoltaic-batteries-offer-30-years-of-functioning-without-recharging.html 
> 
> 
> These are the same types of power source that are used in deep-space 
> probes, such as the Cassini spacecraft.  They consist of a heat source 
> (the radioisotope, Pu238 in the example of Cassini, an alpha emitter, 
> possibly Po210 in this battery) and an array of semiconductor junctions 
> that utilize the Seebeck effect, the same thing responsible for the 
> small voltage created when heating a junction between two dissimilar 
> metals (such as in a thermocouple).  So it is essentially the same as a 
> whole bunch of thermocouples wired in series, with a heat source.  The 
> ones in spacecraft are run brain-splittingly hot, but clearly this one 
> cannot be *that* hot.  Hotter generates more power.
> 
> 

Oh, wait, I see that the radioisotope is a beta emitter (electrons) so 
no heat.  But it is essentially the same effect.  Just guessing:  very 
much like a photocell (photons excite electrons across the band gap) but 
in this case, it is electron collision doing the work.  Must be a 
screaming beta source to get enough power, and all of the electrons 
can't be absorbed so somethings gotta get hot.  I'll study it.  Thanks 
for the link!




-- 
Tony Alfrey
tonyalfrey at earthlink.net
"I'd Rather Be Sailing"