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Perhaps this minor point is obsolete scince I read it long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?
A heat pump needs a compressor run by external power. 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. The heat pump as a whole is not a ambient heat
aboorber. 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.
Bus and buss are both used in the electrical meaning.
Civilization has grown so powerful that inventors must be
productively connected within it.
Aloha,
Charlie
