## Computer! Part-1

As our modern days term goes, a machine that runs certain operations is known as a Computer. In the past before our “Electronic” computers, we had counting devices. Even an abacus or a mechanical calculator is a computer! Yeah, that’s true. Recall the basic requirement of a computer “To perform basic mathematical operations” right!

So what are operated in a computer? Yeah, numbers.. All those counting devices have their own ways of representing numbers.

Now, how do modern days electronic computers take numbers?

Well… Let’s see from the start. The basic way was representing every number using only 0’s and 1’s. We use something called “Boolean algebra” to do so. That’s actually something interesting and maybe you have already done it.

Then, how to use an electronic device to do so?

The basis for this is the voltage( high or low). High represents ‘1’ and low represents ‘0’. Making this basis, we have tried a bunch of devices. The first one was “vacuum tube”, consisted of an anode and a cathode(diode) in a vacuum created tube. Giving a voltage to the cathode release some electrons and are attracted towards the anode( with a higher ‘+’ potential), and by varying the voltage at cathode we get a “high” or “low”( 0 or 1).

Then we had triode, it just had an extra electrode between cathode and anode, which enables the flow of current. Varying the voltage of that extra electrode allows or stops the electrons to flow resulting in a ‘0’ or a ‘1’.

Though they work, those devices have their own disadvantages. Not efficient, bulky and all.

So, to overcome all those disadvantages scientists used “Transistors”. Unlike diodes where they use electrodes, transistor uses something called semiconductor. By using a method called “Doping”, we mix semiconductor with various elements. And create ‘p’type and ‘n’ type. When these n type and p type are arranged alternatively, it forms an npn transistor, with something called p-n junction between p type and n type.

And there is a voltage limit called threshold voltage, the current only passes through the junction, when the voltage is more than threshold voltage. If the voltage is low and the current won’t pass, then that’s a ‘0’ and if the voltage is high and the current passes through, then that’s a ‘1’.

This is how an “Electronic” computer takes in a number. Believe it or not, there might be millions or even more transistors in the electronic device through which YOU are reading this article;)

I want this to be like a big franchise titled “Computer”!!! This is just a beginning part-1, I am left with so much to talk about the machine responsible for making so many things happen, including my blog;)