# how do computer chips work?

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For example nor gates or flip flops.

In: Technology

The most basic idea behind most modern computer chips is the semiconductor. It can be thought of as a sort of electrical valve, a substance which is either an electrical insulator or conductor until a small electrical current is applied to it at which point it changes into the other.

By having a substance that stops current flow until a signal allows it, or allows it until a signal stops it, you can perform logical operations. For example if you have a semiconductor which is normally an insulator you will have two inputs and one output. If only the input which tries to pass the semiconductor is given a current it is stopped by the insulation and there is no output signal. If only the input to the semiconductor is given a current the semiconductor becomes conductive but there is nothing to pass through so there is no output. Only if both inputs are given signals does a current pass through to the output, meaning it is effectively the AND logical operation.

I recommend the book “But how do it know”

It explains processors from the ground up for people who did not study computer science or electrical engineering. It’s worth reading if you really want to know.

http://buthowdoitknow.com/

Let’s talk about a simpler gate first…the AND gate. Imagine a light bulb wired to a battery with two switches, A & B, in series. The light bulb goes on only if both switches are turned on. That’s an AND gate, except in integrated circuits we use transistors instead of switches, and they control other transistors instead of light bulbs.

If you make a similar circuit with the switches in parallel, that’s an OR gate.

With a little ingenuity, you can wire up a [NOR gate](https://i.stack.imgur.com/mXhlO.png) (the inverse of an OR gate). To make it easier and save current, we use two different kinds of transistors, one that turns on with a high voltage, and one that turns on with a low voltage.

By wiring up several logic gates, we can make more complex things like [flip-flops](https://sub.allaboutcircuits.com/images/04196.png). Using both logic gates and flip-flops (and a few other things like transfer gates and multiplexers) we can build up complex logic circuits like an adder. Using a bunch of complex circuits we can make a device like a microprocessor.