It’s a poor sort of memory that only works backwards. ~The White Queen to Alice (Lewis Carroll, Through the Looking Glass) This is the fifth part in my multi-part series on how computers work. Computers are thinking machines, and the first four parts of my series have been on how we teach computers to think. But all of this logic, electronic or otherwise, is useless unless our computers can remember what they did. After logicking something out, a computer needs to remember the result of all that logicking! In this post, I describe how to use the logic gates
how things work
Computer Related / Electronics / logic / etc.
The Boolean Circuit and Electronic Logic, Part 2
If the presence of electricity can be made visible in any part of the circuit, I see no reason why intelligence may not be transmitted instantaneously by electricity. ~Samuel Morse This is the fourth part in my multi-part series on how computers work. Computers are thinking machines, but they can’t do this on their own. We need to teach them how to think. And for this, we need a language of logic. In the first part of the series, I introduced this language of logic, Boolean algebra. In the second part, I described how to formulate complex logical statements
Computer Related / Condensed Matter / History / etc.
The Boolean Circuit and Electronic Logic, Part 1
Living in a vacuum sucks. ~Adrienne E. Gusoff This is the third part in my multi-part series on how computers work. Computers are thinking machines, but they can’t do this on their own. We need to teach them how to think. And for this, we need a language of logic. In the first part of the series, I introduced this language of logic, Boolean algebra. In the second part, I described how to formulate complex logical statements using Boolean algebra. Now, in part three, I lay the groundwork for how we can implement simple Boolean logic using electronics. In
Condensed Matter / optics / Physics / etc.
The Graphene Electro-Optic Modulator
Say we have a beam of light—maybe we made it with a laser. We’d like be able to change the intensity of the beam so that we can alternately brighten and dim it. Moreover, we’d like to be able to do so quickly. Physically blocking and unblocking the beam just isn’t fast enough. So what do we do? The solution is to make an electric switch so we can change how the light behaves via electrical signals. This is an electro-optic modulator (EOM). Two weeks ago, I introduced graphene to you all. And last week, I described some of
Condensed Matter / optics / Physics / etc.
Graphene and Me: My Brush with the Wonder Material
Graphene, a two-dimensional honeycomb lattice of carbon atoms, has made waves in science and technology circles. Last week, I gave a brief overview of the history of the stuff and why it’s special. This week, I’d like to continue the story by talking about applications. Unfortunately for us—and fortunately for society as a whole—graphene has spawned so many new technologies that it’s impossible for me to discuss them all. So instead, I thought I’d talk a single application that has personal value to me. As an undergraduate student, I spent two years in a laser lab studying graphene’s applications
optics / Physics / Quantum Mechanics / etc.
Why The Sky is Blue: Lord Rayleigh, Sir Raman, and Scattering
The Sky is the Daily Bread of the Eyes ~Ralph Waldo Emerson At some point in his or her life, almost every child on Earth asks, “Why is the sky blue?” The question is so prevalent that, to me, it has come to represent the wonder that the world holds for a a child. Adults don’t ask such questions… at least, not unless they’re scientists. Part 1: John Tyndall In 1859, physicist John Tyndall thought he’d found the answer to the sky’s color. His studies of infrared radiation required him to use containers of completely pure air. He
optics / Physics / Quantum Mechanics / etc.
How Things Work: Lasers
You know, I have one simple request. And that is to have sharks with frikkin laser beams attached to their heads! ~Dr. Evil Always look on the bright side …unless you’re holding a laser pointing device. ~Unknown The laser is, without a doubt, one of the most ubiquitous, archetypal technologies of modern times. And it is one of the most direct applications of quantum mechanics. But how do lasers work? It All Starts In The Atom The story starts deep within the atom. I’ve previously discuss the fact that particles are waves and that this forces electrons to have
Condensed Matter / Physics / Quantum Mechanics / etc.
How Things Work: The Field Effect Transistor
I don’t know how to do this on a small scale in a practical way, but I do know that computing machines are very large; they fill rooms. Why can’t we make them very small, make them of little wires, little elements – and by little, I mean little. ~Richard Feynman (1959) As of 2012, the highest transistor count in a commercially available CPU is over 2.5 billion transistors. ~Wikipedia In my article on quantum tunneling, I mistakenly claimed that diodes and transistors made use of this phenomenon. In an effort to correct my mistake, I’m going to explain