https://phys.org/news/2020-10-physicists-circuit-limitless-power-graphene.html?fbclid=IwAR3bSRboKr3_JwpTi53mvunNSfXajohi6jQHJKDhsxHqB4Tpui-LjFYTTjc

Physicists build circuit that generates clean, limitless power from graphene

A team of University of Arkansas physicists has successfully developed a circuit capable of capturing graphene’s thermal motion and converting it into an electrical current.

“An energy-harvesting circuit based on graphene could be incorporated into a chip to provide clean, limitless, low-voltage power for small devices or sensors,” said Paul Thibado, professor of physics and lead researcher in the discovery.

The findings, published in the journal Physical Review E, are proof of a theory the physicists developed at the U of A three years ago that freestanding graphene—a single layer of carbon atoms—ripples and buckles in a way that holds promise for energy harvesting.

The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atoms, known as Brownian motion, cannot do work. Thibado’s team found that at room temperature the thermal motion of graphene does in fact induce an alternating current (AC) in a circuit, an achievement thought to be impossible.

In the 1950s, physicist Léon Brillouin published a landmark paper refuting the idea that adding a single diode, a one-way electrical gate, to a circuit is the solution to harvesting energy from Brownian motion. Knowing this, Thibado’s group built their circuit with two diodes for converting AC into a direct current (DC). With the diodes in opposition allowing the current to flow both ways, they provide separate paths through the circuit, producing a pulsing DC current that performs work on a load resistor

Additionally, they discovered that their design increased the amount of power delivered. “We also found that the on-off, switch-like behavior of the diodes actually amplifies the power delivered, rather than reducing it, as previously thought,” said Thibado. “The rate of change in resistance provided by the diodes adds an extra factor to the power.”

The team used a relatively new field of physics to prove the diodes increased the circuit’s power. “In proving this power enhancement, we drew from the emergent field of stochastic thermodynamics and extended the nearly century-old, celebrated theory of Nyquist,” said coauthor Pradeep Kumar, associate professor of physics and coauthor.

According to Kumar, the graphene and circuit share a symbiotic relationship. Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two.

That’s an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. “This means that the second law of thermodynamics is not violated, nor is there any need to argue that ‘Maxwell’s Demon’ is separating hot and cold electrons,” Thibado said.

The team also discovered that the relatively slow motion of graphene induces current in the circuit at low frequencies, which is important from a technological perspective because electronics function more efficiently at lower frequencies.

“People may think that current flowing in a resistor causes it to heat up, but the Brownian current does not. In fact, if no current was flowing, the resistor would cool down,” Thibado explained. “What we did was reroute the current in the circuit and transform it into something useful.”

The team’s next objective is to determine if the DC current can be stored in a capacitor for later use, a goal that requires miniaturizing the circuit and patterning it on a silicon wafer, or chip. If millions of these tiny circuits could be built on a 1-millimeter by 1-millimeter chip, they could serve as a low-power battery replacement.

—-

I’m having trouble getting my head around this. Why would there be no warming of the resistor from this current? And if there’s no temperature differential, what is the source of the power? What reservoir of free energy is being drained?

dv said:

https://phys.org/news/2020-10-physicists-circuit-limitless-power-graphene.html?fbclid=IwAR3bSRboKr3_JwpTi53mvunNSfXajohi6jQHJKDhsxHqB4Tpui-LjFYTTjc

Physicists build circuit that generates clean, limitless power from graphene

A team of University of Arkansas physicists has successfully developed a circuit capable of capturing graphene’s thermal motion and converting it into an electrical current.

“An energy-harvesting circuit based on graphene could be incorporated into a chip to provide clean, limitless, low-voltage power for small devices or sensors,” said Paul Thibado, professor of physics and lead researcher in the discovery.

The findings, published in the journal Physical Review E, are proof of a theory the physicists developed at the U of A three years ago that freestanding graphene—a single layer of carbon atoms—ripples and buckles in a way that holds promise for energy harvesting.

The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atoms, known as Brownian motion, cannot do work. Thibado’s team found that at room temperature the thermal motion of graphene does in fact induce an alternating current (AC) in a circuit, an achievement thought to be impossible.

In the 1950s, physicist Léon Brillouin published a landmark paper refuting the idea that adding a single diode, a one-way electrical gate, to a circuit is the solution to harvesting energy from Brownian motion. Knowing this, Thibado’s group built their circuit with two diodes for converting AC into a direct current (DC). With the diodes in opposition allowing the current to flow both ways, they provide separate paths through the circuit, producing a pulsing DC current that performs work on a load resistor

Additionally, they discovered that their design increased the amount of power delivered. “We also found that the on-off, switch-like behavior of the diodes actually amplifies the power delivered, rather than reducing it, as previously thought,” said Thibado. “The rate of change in resistance provided by the diodes adds an extra factor to the power.”

The team used a relatively new field of physics to prove the diodes increased the circuit’s power. “In proving this power enhancement, we drew from the emergent field of stochastic thermodynamics and extended the nearly century-old, celebrated theory of Nyquist,” said coauthor Pradeep Kumar, associate professor of physics and coauthor.

According to Kumar, the graphene and circuit share a symbiotic relationship. Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two.

That’s an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. “This means that the second law of thermodynamics is not violated, nor is there any need to argue that ‘Maxwell’s Demon’ is separating hot and cold electrons,” Thibado said.

The team also discovered that the relatively slow motion of graphene induces current in the circuit at low frequencies, which is important from a technological perspective because electronics function more efficiently at lower frequencies.

“People may think that current flowing in a resistor causes it to heat up, but the Brownian current does not. In fact, if no current was flowing, the resistor would cool down,” Thibado explained. “What we did was reroute the current in the circuit and transform it into something useful.”

The team’s next objective is to determine if the DC current can be stored in a capacitor for later use, a goal that requires miniaturizing the circuit and patterning it on a silicon wafer, or chip. If millions of these tiny circuits could be built on a 1-millimeter by 1-millimeter chip, they could serve as a low-power battery replacement.

—-

I’m having trouble getting my head around this. Why would there be no warming of the resistor from this current? And if there’s no temperature differential, what is the source of the power? What reservoir of free energy is being drained?

Yeah, there’s about 4 things in that article that don’t make much sense, “electronics function more efficiently at lower frequencies” I don’t even know what that’s supposed to mean.

I mean honestly normally I’d blow this off as a bunch of crap but it did managed to get published in Physical Review E. It’s not a very high impact journal but it’s a proper journal.

I still think it’s wrong. It’s a bit like a sultana in a salad.

>Yeah, there’s about 4 things in that article that don’t make much sense, “electronics function more efficiently at lower frequencies” I don’t even know what that’s supposed to mean.

not entirely true as an unqualified generalization, but of gates or switching devices the transition time between being off and fully on (getting to Ron) involves power losses, the C of the junctions largely, slows down the rise time, and fall

Come on folks, it’s only four threads down.

“ Physicists build circuit that generates clean, limitless power from graphene
Tau.Neutrino “

SCIENCE said:

Negative Power ¡¡¡

Negative power is an interesting concept. Can you get negative power from negative entropy, temperatures below absolute zero? Or would that be imaginary power?

> A team of University of Arkansas physicists has successfully developed a circuit capable of capturing graphene’s thermal motion and converting it into an electrical current.

This is exactly the scenario prohibited by the second law of thermodynamics.

The article is behind a paywall, but I can read the figures. What we have here is a version fo Maxwell’s demon in which the demon is replaced by a pair of diodes. As energy from thermal fluctuations passes one way through the demon it goes through one diode, as the energy passes back through the demon it goes through the other diode.

Combine the energy from both diodes and you get positive energy out. Only you don’t. The actual power out comes from a battery providing “load” to the system through a resistor. All you’re measuring is the energy generated by the slow discharge of a battery V through the resistor R.

mollwollfumble said:

Come on folks, it’s only four threads down.

my bad

mollwollfumble said:

Negative power is an interesting concept. Can you get negative power from negative entropy, temperatures below absolute zero? Or would that be imaginary power?

Imaginary power is already defined as reactive power, and is very real.

mollwollfumble said:

> A team of University of Arkansas physicists has successfully developed a circuit capable of capturing graphene’s thermal motion and converting it into an electrical current.

This is exactly the scenario prohibited by the second law of thermodynamics.

The article is behind a paywall, but I can read the figures. What we have here is a version fo Maxwell’s demon in which the demon is replaced by a pair of diodes. As energy from thermal fluctuations passes one way through the demon it goes through one diode, as the energy passes back through the demon it goes through the other diode.

Combine the energy from both diodes and you get positive energy out. Only you don’t. The actual power out comes from a battery providing “load” to the system through a resistor. All you’re measuring is the energy generated by the slow discharge of a battery V through the resistor R.

Diodes have a forward bias voltage, in that the power source needs to be above a certain voltage for current to flow. (0.7V generally). If the battery were at that bias voltage, then zero current would flow. As soon as you get a forward boost from anything, current flows. A negative boost does nothing. Unsure what the job of the secone diode in reverse is supposed to achieve though.

transition said:

>Yeah, there’s about 4 things in that article that don’t make much sense, “electronics function more efficiently at lower frequencies” I don’t even know what that’s supposed to mean.

not entirely true as an unqualified generalization, but of gates or switching devices the transition time between being off and fully on (getting to Ron) involves power losses, the C of the junctions largely, slows down the rise time, and fall

The statement is true. Modern electonics need lots of attention paid to the routing of tracks on circuit boards due to the frequency the data they carry. It is a real thing. (Parallel wires carrying high frequency data interfere with each other)

>Diodes have a forward bias voltage, in that the power source needs to be above a certain voltage for current to flow. (0.7V generally). If the battery were at that bias voltage, then zero current would flow. As soon as you get a forward boost from anything, current flows. A negative boost does nothing. Unsure what the job of the secone diode in reverse is supposed to achieve though.

what about diodes that don’t have that, or not much, been a big part of diode development

transition said:

>Diodes have a forward bias voltage, in that the power source needs to be above a certain voltage for current to flow. (0.7V generally). If the battery were at that bias voltage, then zero current would flow. As soon as you get a forward boost from anything, current flows. A negative boost does nothing. Unsure what the job of the secone diode in reverse is supposed to achieve though.

what about diodes that don’t have that, or not much, been a big part of diode development

The only difference between two diodes in that configuration and a piece of wire is the bias – without it, you may as well just use a bit of wire.

Dark Orange said:

transition said:

>Diodes have a forward bias voltage, in that the power source needs to be above a certain voltage for current to flow. (0.7V generally). If the battery were at that bias voltage, then zero current would flow. As soon as you get a forward boost from anything, current flows. A negative boost does nothing. Unsure what the job of the secone diode in reverse is supposed to achieve though.

what about diodes that don’t have that, or not much, been a big part of diode development

The only difference between two diodes in that configuration and a piece of wire is the bias – without it, you may as well just use a bit of wire.

dunno, depends, all sorts of things act like diodes, or can be made to do so, have thresholds and directional characteristics, and one diode i’m thinking of has effectively negative resistance, tunnel diodes for example, and there has been other developments in the field of diodes

but I get your point, two diodes in a circuit that way, opposite parallel, the rudimentary view would have it does nothing except add a voltage drop step in both directions

transition said:

Dark Orange said:

transition said:

>Diodes have a forward bias voltage, in that the power source needs to be above a certain voltage for current to flow. (0.7V generally). If the battery were at that bias voltage, then zero current would flow. As soon as you get a forward boost from anything, current flows. A negative boost does nothing. Unsure what the job of the secone diode in reverse is supposed to achieve though.

what about diodes that don’t have that, or not much, been a big part of diode development

The only difference between two diodes in that configuration and a piece of wire is the bias – without it, you may as well just use a bit of wire.

dunno, depends, all sorts of things act like diodes, or can be made to do so, have thresholds and directional characteristics, and one diode i’m thinking of has effectively negative resistance, tunnel diodes for example, and there has been other developments in the field of diodes

but I get your point, two diodes in a circuit that way, opposite parallel, the rudimentary view would have it does nothing except add a voltage drop step in both directions

Now the question is; why?

Dark Orange said:

transition said:

>Yeah, there’s about 4 things in that article that don’t make much sense, “electronics function more efficiently at lower frequencies” I don’t even know what that’s supposed to mean.

not entirely true as an unqualified generalization, but of gates or switching devices the transition time between being off and fully on (getting to Ron) involves power losses, the C of the junctions largely, slows down the rise time, and fall

The statement is true. Modern electonics need lots of attention paid to the routing of tracks on circuit boards due to the frequency the data they carry. It is a real thing. (Parallel wires carrying high frequency data interfere with each other)

Nah, it’s not. Yes there are engineering considerations that need to be taken into account when designing at higher frequencies but that just means that electronics works differently, not worse. Would 5G work better if its frequency was lower?

roughbarked said:

transition said:

Dark Orange said:

The only difference between two diodes in that configuration and a piece of wire is the bias – without it, you may as well just use a bit of wire.

dunno, depends, all sorts of things act like diodes, or can be made to do so, have thresholds and directional characteristics, and one diode i’m thinking of has effectively negative resistance, tunnel diodes for example, and there has been other developments in the field of diodes

but I get your point, two diodes in a circuit that way, opposite parallel, the rudimentary view would have it does nothing except add a voltage drop step in both directions

Now the question is; why?

The included battery suggests that it is to allow energy to be extracted from half the process. Maybe there is some sort of energy loan, like hawking radiation / zero point energy.

sounds like bullshit