However, the important thing is that you understand the concepts of voltage and current flow. Mathematical analysis of circuits can be quite difficult, and there are many, many different circuit elements which can behave in very non-linear and confusing ways. This electrical circuit is analogous to a very similar "gravitational circuit":Ī "gravitational circuit" with a high potential (bucket of water on a hill) and current flowing from a high potential to a low potential through some resistance (in the form of a water wheel). Ohm's law says that the current is proportional to the voltage by a factor of \(1/R\), where \(R\) is the resistance. As it flows through the resistor, energy is dissipated as heat into the environment.
With these two elements (a voltage source and a resistor), we can draw a basic circuit:Ĭurrent flows from high potential (the plus sign) to low potential (the minus sign). In the same way, there is a circuit element called a resistor which prevents electrons from flowing through wires quickly. As water flows from high to low, it can encounter resistance which slows down the current, such as a water wheel. Wires allow electrons to flow through them, towards higher potential and away from lower potential - just like pipes allow water to flow from higher regions to lower ones. The water has a lot of potential energy - if we allow it out of the bucket, it will gain energy and fall off the hill. In that analogous system, a voltage source is a hill with a bucket of water on it.
When thinking of electric potentials and currents, it can be very helpful to imagine an equivalent system but with a gravitational field instead of an electric field. A voltage source is an abstraction which simply allows us to dictate the electric potential at a given point in the circuit, relative to some point in the circuit which we deem at zero potential (called ground). The first important concept is that of a voltage source, or a battery. Different types of materials have different effects upon electric fields and the movement of electrons, and this allows us to conjoin different materials to create circuits. Particles known as electrons travel in the direction opposite the electric field, creating a current of electrons. Circuitsįundamentally, all electronics operate on the basis of a set of equations known as Maxwell's equations, which dictate how electric and magnetic fields propagate. With that said, let's begin with circuits. Just note that every topic I mention has, essentially, a field and a half solely devoted to it. Given the rather large scope, I'm going to end up leaving out a lot of information about every topic I discuss.
In this series of blog posts, I'd like to introduce you to many of the layers of abstraction bridging the gap between the laws of physics and assembly language. But while understanding every single layer of abstraction to its fullest extent is practically impossible, it's incredibly fascinating how modern computers are built and what physical principles allow them to function. We've built up so many layers of abstraction that the vast majority of people using computers - even the vast majority of highly technical programmers - don't know (and don't need to know!) how it all works on the inside. On the inside, a computer is a monstrously complex beast, with layers upon layers of abstraction which ultimately boil down to electrons running through silicon, obeying the fundamental laws of physics. Clarke)įor many years, I studied computers without ever understanding how they work. Any sufficiently advanced technology is indistinguishable from magic.