This is your brain on power

[Coppersmith]

I saw this quote from National Geographic's "Your Brain" on CBS Sunday Morning:

"Your brain uses 20 watts of power..."

Now I'm curious about the voltage and amperage. I don't have enough info to do an Ohm's Law calculation.

 

[kwired]

If that 20 watts is fairly continuous then we should need about 400 calories a day just to support brain activity

 

[ptonsparky]

I more than generate enough power. I bank what isn’t needed.

 

[kwired]

I more than generate enough power. I bank what isn’t needed.

I have plenty of reserves myself.

 

[drcampbell]

Wikipedia says that each neuron fires on less than 100 mV. No mention of current, but if billions & billions of neurons collectively require only 20 W, it's not much.
https://en.wikipedia.org/wiki/Neuron

Popular Science says that 2 milliamps to the scalp doubles your brain performance but, like every licensed electrician I've encountered, doesn't recommend doing it yourself.
https://www.popsci.com/technology/a...in-improves-video-game-skills-researcher-says

 

[Jraef]

I have plenty of reserves myself.

My brain could live on for about 300 years on my reserves then.

 

[JFletcher]

I remember reading somewhere before the human body generates about a hundred watts per hour. I also remember going to York Power Station as a kid and riding the bike they had hooked to a little Dynamo. you could just about power a hundred watt bulb peddling as fast as possible. then they said that at that rate you would have to pedal for something like 3.6 days to generate the amount of energy contained in a gallon of gas or maybe it was a pound of coal

 

[Ingenieur]

Wikipedia says that each neuron fires on less than 100 mV. No mention of current, but if billions & billions of neurons collectively require only 20 W, it's not much.
https://en.wikipedia.org/wiki/Neuron

Popular Science says that 2 milliamps to the scalp doubles your brain performance but, like every licensed electrician I've encountered, doesn't recommend doing it yourself.
https://www.popsci.com/technology/a...in-improves-video-game-skills-researcher-says

20 w = 0.1 v x i A so i = 200 A
if we assume 1 mil neuron firing at any given instant
200/10e6 = 2 uA per neuron

what is the avg power at a given point from all emf? voltage gradient?
radio, cell, tv, power lines, etc

edit: The human brain has about 100 billion of them. Each neurons fires (on average) about 200 times per second. And each neuron connects to about 1,000 other neurons.

much smaller i
200e6 firings per uSec

 

[Ultrafault]

Have you guys forgot your thermo? One Watt is one Joule per second. It is a unit that can be used to express all energy, heat, mechanical, chemical, and electrical. Watts law would not apply. Unless you were all joking, in which case I am just bieng that internet guy who cant recognise sarcasam.

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[Ingenieur]

Have you guys forgot your thermo? One Watt is one Joule per second. It is a unit that can be used to express all energy, heat, mechanical, chemical, and electrical. Watts law would not apply. Unless you were all joking, in which case I am just bieng that internet guy who cant recognise sarcasam.

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what???
W = J/s or dE/dt, ie the rate of energy transfer
as in across the neuron/synapse

20 W = 20 J/s
100e9 neurons firing 200 / sec at 100 mV / neuron or junction
you have everything you need

 

[Ultrafault]

what???
W = J/s or dE/dt, ie the rate of energy transfer
as in across the neuron/synapse

energy can have more forms than electrical. A Watt can express them. for instance I can heat a space with gas and express the energy added to the system in watts. I can also lift a brick with my hand and express the added potential energy in watts.

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[Ingenieur]

energy can have more forms than electrical. A Watt can express them. for instance I can heat a space with gas and express the energy added to the system in watts. I can also lift a brick with my hand and express the added potential energy in watts.

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you are stating the obvious
chemical, thermal, nuclear et al

the point is you said P= v x i does not apply
if we assume the 20 W to be electrical (since this is an electrical forum and the post wss more or less tongue in cheek) it does apply

it was a smug insult against all forum members
like you are smarter
lighten up

 

[Ultrafault]

you are stating the obvious
chemical, thermal, nuclear et al

the point is you said P= v x i does not apply
if we assume the 20 W to be electrical (since this is an electrical forum and the post wss more or less tongue in cheek) it does apply

I see, I did not assume that the power was even partialy electrical. Ok I guess I am bieng that guy.

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[Coppersmith]

Wikipedia says that each neuron fires on less than 100 mV. No mention of current, but if billions & billions of neurons collectively require only 20 W, it's not much.
https://en.wikipedia.org/wiki/Neuron

Popular Science says that 2 milliamps to the scalp doubles your brain performance but, like every licensed electrician I've encountered, doesn't recommend doing it yourself.
https://www.popsci.com/technology/a...in-improves-video-game-skills-researcher-says

"Now it appears zapping your brain with a 9-volt battery will make you better at video games, at least according to one researcher."

Wow. This might be the edge I need to beat all those 10 and 12 year olds who kick my behind at Overwatch.

 

[Coppersmith]

energy can have more forms than electrical. A Watt can express them. for instance I can heat a space with gas and express the energy added to the system in watts. I can also lift a brick with my hand and express the added potential energy in watts.

you are stating the obvious
chemical, thermal, nuclear et al

the point is you said P= v x i does not apply
if we assume the 20 W to be electrical (since this is an electrical forum and the post wss more or less tongue in cheek) it does apply

it was a smug insult against all forum members
like you are smarter
lighten up

Actually Ultrafault, I was not offended and thought you made a good point. I had assumed the energy is electrical, but it could be chemical energy they are talking about in the National Geo article. I didn't read it. It's probably not nuclear unless you have developed super powers from being in an industrial accident.

 

[roger]

"Your brain uses 20 watts of power..."

So if we look at an incandescent lamp, a 20 watt lamp is pretty "dim" so I wonder if the term "dim wit" is just a coincidence.

Roger

 

[retirede]

"Now it appears zapping your brain with a 9-volt battery will make you better at video games, at least according to one researcher."

.

Even better than eating Tide Pods?

 

[roger]

energy can have more forms than electrical. A Watt can express them. for instance I can heat a space with gas and express the energy added to the system in watts. I can also lift a brick with my hand and express the added potential energy in watts.

My outboard engine is rated in KW and HP.

Roger

 

[Coppersmith]

I can also lift a brick with my hand and express the added potential energy in watts.

Dropping the brick on your toe is expressed differently. :rant:

 

[ggunn]

I remember reading somewhere before the human body generates about a hundred watts per hour.

That makes no sense. A Watt is a rate, not a quantity.