> Oh, well. So, I guess I was all wet, after all. Jed wishes he had that luck I am sure!
> If that's not what he's doing, then I don't know what experiment he's > thinking of performing It's all in the subject line: 'diode array' in 'photodiode array', a photodiode is a diode (cathode = N doped side on top I believe), so a photodiode array (the Japanese solar cell) is a diode array, especially in the dark, and a ready-made one, which could save Charlie a lot of development time/efforts/money. Michel ----- Original Message ----- From: "Stephen A. Lawrence" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, November 14, 2007 3:54 PM Subject: Re: [Vo]:Re: diode array in photodiode array > > > Michel Jullian wrote: >> 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. > > Oh, well. So, I guess I was all wet, after all. > > In the past Charlie was talking about rectifying noise from a resistor using > LEDs. Recent posts > of his included the observation that high-value resistors are better for > this, which indicated to > me that he was still pursuing that. I just assumed this post was along the > same line, and he was > going to feed noise from a resistor to the array. And the reason for doing > it /in/ /the/ /dark/ > is that ambient light will drown out the effect in a normally lit room. > > If that's not what he's doing, then I don't know what experiment he's > thinking of performing, and > I clearly didn't understand his post at all. > > (Sorry, Charlie.) > > >> >> 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 >>>>> >>>> >> >> >
