# Article: Computer Under The Hood

PC: Under the Hood

7 October 2006

We must have heard this over a million times. Computers donâ€™t think with numbers and alphabets but with just 1â€™s and 0â€™s. Some of us already know this but todayâ€™s article is dedicated to the budding Engineers and hobbyists! The reason for writing this article is not to teach how a computer is made, but how it functions. How it communicates and store data.

Keeping in mind time is money lets start with the hardware. Itâ€™s pure Electronics. All the ICâ€™s, boards and cards have resistors, capacitors, transistors, inductors and diodes. Yes, surprisingly all the complicated circuitry is made up of just the 5 components! How many? Uncountable!! To get an idea, try counting the number of sugar grains in a cup of sugar. A single IC can contain from 30 to 300 million transistors. Other components total about half the number of transistors. Imagine, how these millions of components let you play games, watch movies, write boring articles and surf the web?

Internally the computer calculates and makes decision at astoundingly rapid speeds. This speed is only possible because of electricity since its made up of electrons, which are, well, pretty darn fast! The transistors act like switches. In electronics and computer speak, switch on is 1 and switch off is a 0. Never forget this!

Did you know switches can make decisions? How? Here you go â€“

â€œIf switch 1 or switch 2 is on then turn on switch 3 otherwise keep it off.â€

Well, this on/off dance can take place about a million to trillion times a second! This decision making is carried out by a combination of transistors called Logic gate - Wikipedia.

Next Article/Tutorial will be on Logic gate - Wikipedia in general and how to see them in action using 74xx series ICâ€™s.

Some Questions to get the cogs moving:

1. How many transistors are there on a single Cell Processor of Playstation 3?
2. How many of you ever owned a 286 or 386 or 486? (I had a 286 and a 386 10 years ago.)
3. How much memory could a 286, a 386 or a 486 address?
4. Whats the Voltage of logic 1 and logic 0? (give general ans and/or range, but specify)

NOTE: Some of the Q asked are important for first and second year engineering.

-xheavenlyx
Have Fun!

## Replies

• Neha
Nice article!!

Being involved in Computers I knew most of it but never thought of putting it in such a good article.

The answer to the first question is 234 million transistors.
• Kaustubh Katdare
xheavenlyx
4. Whats the Voltage of logic 1 and logic 0? (give general ans and/or range, but specify)

-xheavenlyx
Have Fun!
Logic 1 corresponds to 5 volts and Logic 0 corresponds to Earth.

-The Big K-
• xheavenlyx
Nice to see the answers 😁

Well, soon ill write the logic gates Article. I guess while writing these article my basic idea is to spark curiosity. If anyone got more suggestions, please let me know.

;-)
• instruite
The_Big_K
Logic 1 corresponds to 5 volts and Logic 0 corresponds to Earth.

-The Big K-
This was when the logic level was introduced
Now-a-days we get devices/components/ICs with various power supply voltage ratings (like 3.3V, 2.6V) so these logic level definitions have also changed
In general it can be said that
Logic 0 range = 0 upto 0.4 x Vcc (Vcc=power supply voltage of IC)
Logic 1 range = 0.8 x Vcc upto Vcc
• Kaustubh Katdare
instruite
This was when the logic level was introduced
Now-a-days we get devices/components/ICs with various power supply voltage ratings (like 3.3V, 2.6V) so these logic level definitions have also changed
In general it can be said that
Logic 0 range = 0 upto 0.4 x Vcc (Vcc=power supply voltage of IC)
Logic 1 range = 0.8 x Vcc upto Vcc
Thanks for the information, Instruite 😀

xHx : Post answers to your questions and float new set of questions related to the article. 😁

-The Big K-
• xheavenlyx
Good replies! Well, the answer Neha gave for PS3 transistors is kinda correct. According to the first press conf of Sony it has about 300+ million transistors at a thickness of 90nm on 8Layers of metal. Where did you get that number Neha? 😀 it was close.

You too are right on the voltage levels. Though sometimes it can even depend on temp, whcich is an acceptable level.

My next set of questions are:

1. Whats the safe range of temperature at which a home PC can function?

2. Since the computer calculates in bits and bytes. In the lowest level of internal working, each instruction written in C or C++ or Java or anyother language is first converted into Asembly Language. How many bits is a single instruction till Pentium 1. ( I am not sure when the number of instr. bits was increased but it was gradual. So just give the most common one)
• Neha
2. Since the computer calculates in bits and bytes. In the lowest level of internal working, each instruction written in C or C++ or Java or anyother language is first converted into Asembly Language. How many bits is a single instruction till Pentium 1. ( I am not sure when the number of instr. bits was increased but it was gradual. So just give the most common one)
Nice Work!!

8 bits maybe(I am not sure)😕
• xheavenlyx
Thats correct neha, even now, we have 8 bit basic. But some new processors have 16 to 32 bits too, still its processed byte wise or parallely 2 bytes at once.
• Kaustubh Katdare
xHx, we are waiting for the next article. Few CEans, who I know personally, told me that the articles are good and CE should have more of them.

-The Big K-
• xheavenlyx
Biggie, for now this month i am not sure of much. But if time permits I can write about something I am working on. Maybe an introduction on MATLAB since it has got amazing tutorials, ill just need to tell people about it.
• A SudhaKar
Perfect Article,

Hope you would have got all those answer.

Just post here,

So that all could know it .

Thanks and Regards,
A.SK...
• xheavenlyx
I guess the readers have answered most of the questions. Read the whole post, and nayway the questions arent that difficult 😀

You are reading an archived discussion.

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