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bio website daniel.farrell.name
location Tokyo, Japan
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visits member for 4 years, 3 months
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I know how to use the grey square -- do you?


2d
comment When they say the universe was the size of a baseball about a billion billion billion billionth of a second
It means the whole universe. This is important cosmological point because inflation solves the horizon problem (the near uniform temperature distribution of the night sky).
2d
answered Lens to optimize field of view through a tube
Apr
19
comment Optical system for cloning an image of a light source?
This already does what you want (3 criteria in your question). I don't understand what you are talking about!
Apr
19
comment Optical system for cloning an image of a light source?
I don't think you understand. Mirror 2 and 3 reflect light towards both eyes!
Apr
19
answered Optical system for cloning an image of a light source?
Apr
19
comment Optical system for cloning an image of a light source?
Actually if you need to preserve the divergence then it's easier with a second mirror.
Apr
19
comment Optical system for cloning an image of a light source?
Seriously you can do this with just the two components I said. Think about it. I can't draw a diagram right now.
Apr
19
comment Optical system for cloning an image of a light source?
50:50 beam splitter and a 45 degrees mirror will do it.
Apr
15
comment How does a photon drive out the electrons in a solar cell?
This is complicated. You will have to understand band structure of semiconductors, and then semiconductor device physics to get a full answer. However, you can also describe the operation of a solar cell purely with thermodynamic, but as you are asking about the actual mechanics I don't think this is what you want. I would suggest reading Jenny Nelson's of Peter Würfel's solar cell books. It's too much to cover in a single answer.
Apr
13
comment By what maximum amount can we concentrate sunlight?
The factor of two is cancelled when performing the angular integrations.
Apr
13
revised By what maximum amount can we concentrate sunlight?
Showing working.
Apr
13
revised By what maximum amount can we concentrate sunlight?
Added the photovoltaics tag
Apr
13
suggested approved edit on By what maximum amount can we concentrate sunlight?
Apr
13
comment By what maximum amount can we concentrate sunlight?
This is correct and gives the general maximum solar concentration limit. Write an alternative answer that backs up your point if you have something to contribute.
Apr
12
answered By what maximum amount can we concentrate sunlight?
Apr
12
comment Increasing the efficiency of solar cell systems
Easy to explain but open a new question because it will involve another diagram and I don't want to clutter this answer.
Apr
12
revised Increasing the efficiency of solar cell systems
Add tutorial on DeVos's work.
Apr
12
comment Increasing the efficiency of solar cell systems
This is not a duplicate of the "why do solar panels have mirrors". This question is asking about hybrid photovoltaic-thermal energy conversion which has some very interesting thermodynamic properties. Vote to keep open.
Apr
12
answered Increasing the efficiency of solar cell systems
Apr
11
answered Reverse Recovery Current of a diode