Well no, it seems he wants to use the photocell (consisting in many tiny photodiodes in parallel) by itself, or maybe with a resistor, to see if it can rectify thermal noise in the dark.
Michel ----- Original Message ----- From: "Stephen A. Lawrence" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, November 14, 2007 3:01 PM Subject: Re: [Vo]:Re: diode array in photodiode array > > > Michel Jullian wrote: >> Hi Charlie, >> >> It certainly will if you cool it, otherwise it should radiate exactly >> as much energy (blackbody radiation) as it receives, or do I >> misunderstand the concept of thermal equilibrium? > > As an exercise in seeing whether I understand what Charlie's getting at, I'll > try to answer your > question, and we'll see if I'm all wet. > > The key here is the reason Charlie's using LEDs, not ordinary diodes. > > If you look at the current/voltage curve of an ordinary diode, it's > essentially linear at 0 volts > (it's an exponential, but close to zero we can ignore all but the linear > term). This is what the > model says; checking it with an actual diode is a little tricky since the > currents involved are > tiny. > > The point is there's no sharp cutoff down there -- at ~ 0 volts a diode > conducts about equally > well forward or backwards. The "cutoff" comes at ~ 0.6 volts forward bias > (for a silicon P/N > diode) where dV/dI plunges rapidly to something close to zero. > > A consequence of this is that if you hook a diode, a noisy resistor, and a > capacitor in a loop, > the capacitor isn't going to charge -- the voltage on the diode is going to > be very close to zero, > and in that range, the diode just acts like a resistor. In other words, it > leaks like a sieve. > No joy there if you want practical free energy. > > Charlie's idea is that, if he uses an LED, even though noise on the resistor > may be able to sneak > through the diode either way (due to the low voltage), once in a while a > noise pulse will be high > enough to kick a few electrons over the forward barrier voltage, and a light > pulse will come out. > The light then leaves the circuit, and its energy can't be recaptured by the > "leaky" diode. > > A photocell nearby will catch the light, and turn it back into electricity. > The photocell will be > putting out (noisy) DC, not AC, and can be used to charge a capacitor > directly. > > So, overall, the idea seems to be to use the LED in order to do an end-run > around the fact that > diodes aren't ideal. > > I started a series of measurements on diodes at low voltage a long, long time > ago, in a lab course > in school (dropped the course, never finished the measurements). I've been > meaning to do that > experiment over again a little differently from the way we were doing it then > (use JFETs instead > of a VTVM), and also check one other thing: Can an LED "run backwards" and > operate as a solar > cell? I don't know but I suspect the answer is "yes", which could throw an > additional monkey > wrench into the works when trying to use LEDs to cohere noise. > > >> >> Aloha, Michel >> >> ----- Original Message ----- From: "Charles M. Brown" >> <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, >> November 13, 2007 9:52 PM Subject: [Vo]:diode array in photodiode >> array >> >> >>> Vortexians, >>> >>> Looking at the array of hexagonal concentrators and spherical photo >>> diodes in: >>> photodiodeshttp://www.technologyreview.com/Energy/19696/?nlid=662 I >>> see a lot of small diodes in parallel so I will try to get one and >>> see if it aggregates rectified Johnson noise in the dark. >>> >>> Aloha, Charlie >>> >> >> >
