The world's powerful Switch

Simple things build powerful things.We are surrounded by so many engineering marvels, if we dig a little deep we find simple mechanisms that drive them. One such thing that we use every day, which literally controls everything from a power grid to a little toy is a switch. A switch is a simple device for controlling the flow between 2 ends.

Simple things build powerful things

What can we build from these switches?A circuit that turns the light on/off. Yes…But thats too boring.Since this is my forst blog post I want to build more than just lighing the bulb.

Lets build a computer using a switch!!!

Thats totally absurd.How can we build a computer using a switch!! Impossible!! Hmmm….. May be it is possible to build one….

Lets work out the math.

How do we build one? Lets start from the ground by bulding AND gate. The logic AND outputs high if all the inputs are high.

    ....! ....! ....
   ___              .
    -              .
    .......`O`......
    
    AND using Switches
    
 Imagine those ! symbols as switches.`0` is our Glowy BULB.[Stop thinking of it as birthday cake]

If one of the switch is closed the bulb will not glow. The Bulb Glows only when both switches are closed.So we have our AND gate ready. Great going!!!

The OR. The logic OR outputs high if any of its inout is high.

       ....! ....
       .        .
    ....        .......
    .  .        .     .
    .  ....! ....     .
   ___               `O`
    -                 .
    ...................
    
    OR using Switches

Even if one of the switch is closed the bulb glows.We have our OR.

The naughty NOT: you say high i say low, I say low you say high…..

NOT gate using Switches

Here is the logical way of representing the logic gates.

In order to build a computer you need basic logic gates.(Recall Electronics 101 The AND’s and the OR’s and the NOT’s).Thats the holy grail!! If you can build these gates may be we inch towards the massive goal.

Now that we have all our ingredients ready, we can cook our meth now.

Next up, Lets add some numbers.

I am sure all the electronics 101 bells are ringing now!!! Nothing fancy. Just work out the math.

Lets ask a simple question. How Fast the above switch adder circuit can add numbers?

It depends on how fast one turns the switches on and off. The faster the switches are turned on/off the faster the results.

If at all computers were built using switches it would be extremely slow.Imagine the speed being measured in how fast you turn those switches on and off manually. This is where you put on the engineers cap and say I am an engineer.Just kidding :)

The question we need to ask is

“Is there any other way we can turn these switches on/off very fast?”

BRAVO!!!

Thanks to Bardeen, Brattain, and Shockley who shocked the world with an award winning innovation,an electronically controlled switch aka TRANSISTOR. All transistor is nothing more than an electronically controlled switch with which we can build all the logic gates using these transistors.

The Logic gates to the Flipflops to Shift Registers to adder circuts to the MUX to the DEmux to Micro Controllers to the memories to the i/o ‘s , are all built using these tiny switches.

Are we ever going to build the mighty computer?We will get there sooon.Relax ;)

Its about the journey, Not the Destination.Enjoy the ride!!!