Just saw on r/todayIlearned that the MOS transistor (or MOSFET) is the most produced piece of technology ever. I then looked it up on Wikipedia to try and understand what it is/does and I’m still totally lost. ELI5?
In: Technology
a relay works by having an electromagnetically actuated switch.
the voltage across the POWER + and – connections is controlled by having voltage across the SIGNAL + and – connections.
a mosfet works in more or less the same way. the RESISTANCE of the connection between the Source (S) and Drain (D) connections on the MOSFET is controlled by the voltage difference between the GATE (G) and Body (B) connections.
just as your relay can be Normally Open (signal turns the relay off) or Normally closed (signal turns the relay ON), MOSFETS can also be normally open (P channel) or normally closed (N channel)
Just like any transistor it allows you to control how much electricity flows through it using electricity itself. This guy on Youtube has made a nice explanation https://youtu.be/o4_NeqlJgOs
It is a tiny electronic switch without moving parts.
With switches you have on/off or 1/0 which can be used to generate numbers and do math (true or false logic) in binary, similiar to how redstone in Minecraft works.
Any non-purely analgue device, from your computer to your coffee machine works because of billions of these switches doing math.
A MOSFET is a specific type of transistor. It’s an amplifier, although used in a certain way it can be thought of like a digital switch. It has 3 main terminals: A Source, a Drain, and a Gate. The current that passes between the Source and Drain is controlled by the Gate voltage.
Since a small Gate voltage can control a large current between Source and Drain, the MOSFET can amplify signals. If the only signals the Gate ever gets are small or large, then the transistor is being used like a digital switch. You can use the output of one to control the inputs of others, and they can control others, and so on and so forth. This allows us to create circuits that contain a bunch of simple devices (MOSFETs mostly) but build them up into things that can perform complex logical functions. Like a microprocessor.
The reason that it is the most produced piece of technology is that we’ve learned over the last half century or so to put many MOSFETs onto a single “chip”, creating an Integrated Circuit. And by making them smaller and smaller, we’ve gone from putting just a handful onto one chip to literally putting billions on a chip. A single semiconductor wafer with many ICs on it can have hundreds of billions of transistors, or even over a trillion. When you make that many of something at one time, you end up with an awful lot of them.
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