----- Original Message ----- From: "Charles M. Brown" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, March 08, 2007 2:24 PM Subject: [Vo]: Re [Vo] FET rectification-refrigeration-models-part of Proof of capturing ambient temperature energy
> On Thu, 8 Mar 2007 11:20:10 +0100 > "Michel Jullian" <[EMAIL PROTECTED]> wrote: >> >>----- Original Message ----- >>From: "Charles M. Brown" <[EMAIL PROTECTED]> >>To: <[email protected]> >>Sent: Thursday, March 08, 2007 5:47 AM >>Subject: Re: [Vo]: Proof of capturing ambient temperature >>energy >> >> >>> On Wed, 7 Mar 2007 20:48:47 +0100 >>> "Michel Jullian" <[EMAIL PROTECTED]> wrote: >>>>To avoid the voltage drop associated with a diode, which >>>>is huge compared to the noise signal, one could use smart >>>>auto-controled switches (fets) instead, which would only >>>>connect the noise source to the capacitor when the source >>>>is at a higher potential than the capacitor. This kind of >>>>diodelesss rectification scheme is used in low voltage >>>>switchmode power supplies, and is called "synchronous >>>>rectification". >>>> >>>>A kind of "sample and hold" which would resample every >>>>time the noise signal gets higher than the storage >>>>voltage. >>>> >>>>Now would the whole system be able to power itself plus >>>>some excess in isothermal conditions, where the switches >>>>themselves exhibit thermal noise? That's the question. >>>> >>>>Michel >>>> >>> >>> Charlie's comment 1: >>> I think that gates and drains on one buss / sources on >>>the >>> other buss FETs could substitute for diodes in an >>>array. >> >>I think you mean "bus" ;-) >>No it wouldn't work this way, simulate this and you'll >>see what I mean, maybe we could all agree to use LTSpice >>so we can share simulations? >> >>> Johnson noise in the channels will be rectified as it >>> interacts with the gate. >>> This would be harder to fabricate even if the gate is a >>> metal mesh. Sampling and holding is not needed. >> >>"sample and hold" was an attempt to describe how a >>synchronous rectifier works: every value higher than the >>previously sampled value is "sampled and held" sort of. >>But "zero voltage drop rectification", which is the end >>result, is a much better description. >> >>Michel >> > Charles M Brown > Perhaps this minor point is obsolete scince I read it long > ago: A depletion type FET has less gate to source and gate > to drain capacitance (beyond the channel) than an > enhancement type because the gate works to pinch off part > of the channel far from the metal of the source and drain. > If all the FETs are in parallel with the gates at drain > voltage than the only thing that Johnson noise can effect > separately is each channel. When part of each channel > drifts positive in an N type depletion FET it becomes > pinched into higher resistance. When part of each channel > drifts negative in an N type depletion FET it remains > conductive. Therefore positive excursions of the channel > are surpressed. > > Will spice show the increased performance of InSb? If you can find a spice model for it, yes. But what I was saying is that an N type FET (any) with its drain and gate connected to a random low voltage (<100mV right?) supply and its source connected to the output capacitor will not rectify the supply voltage, as would be obvious to any EE and as can easily be seen by spice-simulating it. Or wasn't that what you meant? > A heat pump needs a compressor run by external power. Not necessarily, cf Peltier modules. > The > compresser energy and compressor losses due to > inefficiency must be expressed as heat in a hot side > radiator (possibly including the compressor case). The > refrigerant must also release heat to the hot side > radiator. So? > The heat pump as a whole is not a ambient heat > aboorber. I don't understand what you mean. Of course it absorbs ambient heat, it pumps it from one place (e.g. ambient air outside your house) to another place (e.g. ambient air inside your house). > I believe that heat pumps are heavier than diode > arrays so bootstrapping heatpumps to diode arrays will > make things worse. Part of the diode array's electrical > output would be consumed by the compressor. > > I snipped away Michel's comment about models being > susceptible to disproof by better models. I hope that > better understanding will lead to succesful ambient heat > absorbing / power producing devices. I didn't get any of the above, did I mention heat pumps in relation to diode arrays, or comment about models being susceptible to disproof by better models? > > Bus and buss are both used in the electrical meaning. Ah OK, my English. > Civilization has grown so powerful that inventors must be > productively connected within it. Agreed. Michel > > Aloha, > > Charlie >
