How does the computer know whether a binary pattern results in the display of a letter or number?

You (or the compiler you use) have to explicitly tell the computer how to interpret a bit string. So when you write code you'd have to specify "This is a character" or "This is a binary number", high level programming language have functions to make that easier.

I didn't understand how 4 bits can represent 16 values.Could you please explain.Thanks

If we have 4 bits and each can be one of two values, then the number of combinations one can make with 4 bits is equal to 2*2*2*2 = 2^4 = 16.

"At 11:47, what are electromechanical transistors?"

it focuses on the interaction of electrical and mechanical systems as a whole and how the two systems interact with eachother.

Bits are binary digits (0 and 1)

whenever i see computer specification there written 32 bit 64 bit 128 bit i always wonder what this means

32 bit and 64 bit refer to the addressable memory. A 32 bit computer can only use about 4 GB of RAM, whereas a 64 bit computer can use about 16 exabytes of RAM. 64 bit computers can often do more calculations per second, so they are faster.

How do just two numbers make up an entire device

Computers can't understand statements or requests like "Please put the picture of dogs on the top right page of the screen". For computers, it's total gibberish. The best way for computers to understand our requests are by the most simple types of questions possible - YES or NO. 1's and 0's simply respond to the computer asking "Does variable x = y?". So whatever question the computer asks, we can say YES or NO, 1 or 0. These questions can range from anything from "what is this letter" to "where is this item's coordinates". At the end of the day, computers just run on "should I do this", numerous times.

why are bits used to represent everything?

Computers only understand information when it is in binary or in binary digits (Bits): 0 and 1. So all we do is converted to bits so the computer can understand.

Main content

Computers and the Internet

Course: Computers and the Internet > Unit 1

Lesson 1: Bits and bytes

Bits (binary digits)

Google Classroom

Computers store information using bits. A bit (short for "binary digit") stores either the value start text, 0, end text or start text, 1, end text.

What fits in a bit?

A single bit can only represent two different values. That's not very much, but that's still enough to represent any two-valued state.

Is a lightbulb on or off?

State	Bit
A lightbulb that's off	start text, 0, end text
A lightbulb that's on	start text, 1, end text

Is a button enabled or disabled?

State	Bit
An enabled button that says "Submit"	start text, 0, end text
A disabled button that says "Submit"	start text, 1, end text

Is the current time AM or PM?

State	Bit
An alarm clock that says "9:35 AM"	start text, 0, end text
An alarm clock that says "9:35 PM"	start text, 1, end text

Check your understanding

Consider this settings screen for a Khan Academy user:

Which of the settings can be stored in a single bit?

Sequences of bits

Computers use multiple bits to represent data that is more complex than a simple on/off value.

A sequence of two bits can represent four (2, squared) distinct values:

start text, 0, end text, start text, 0, end text, start text, 0, end text, start text, 1, end text, start text, 10, end text, start text, 11, end text

A sequence of three bits can represent eight (2, cubed) different values:

start text, 0, end text, start text, 0, end text, start text, 0, end text, start text, 0, end text, start text, 0, end text, start text, 1, end text, start text, 0, end text, start text, 10, end text, start text, 0, end text, start text, 11, end text, start text, 10, end text, start text, 0, end text, start text, 101, end text, start text, 110, end text, start text, 111, end text

A sequence can represent many things: a number, a character, a pixel. Plus, the same sequence can represent different types of data in different contexts. The sequence start text, 10, end text, start text, 0, end text, start text, 0, end text, start text, 0, end text, start text, 11, end text could represent 67 in a calculator application while also representing the letter "C" in a text file. Learn more in our lessons on Binary numbers and Storing text in binary

Check your understanding

How many different values can four bits represent?

Physical storage

Computers typically store bits using electromechanical transistors which can map electrical signals to either an on or off state. Learn more in our article From electricity to bits or this video on how transistors work.

🙋🏽🙋🏻‍♀️🙋🏿‍♂️Do you have any questions about this topic? We'd love to answer— just ask in the questions area below!

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Jess S
Posted 3 years ago. Direct link to Jess S's post “How does the computer kno...”
How does the computer know whether a binary pattern results in the display of a letter or number?
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(26 votes)
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- Martin
  Posted 3 years ago. Direct link to Martin's post “You (or the compiler you ...”
  You (or the compiler you use) have to explicitly tell the computer how to interpret a bit string.
  
  So when you write code you'd have to specify "This is a character" or "This is a binary number", high level programming language have functions to make that easier.
  Comment on Martin's post “You (or the compiler you ...”
  (38 votes)
Shwetha
Posted 3 years ago. Direct link to Shwetha's post “I didn't understand how 4...”
I didn't understand how 4 bits can represent 16 values.Could you please explain.Thanks
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(7 votes)
Answer
- KLaudano
  Posted 3 years ago. Direct link to KLaudano's post “If we have 4 bits and eac...”
  If we have 4 bits and each can be one of two values, then the number of combinations one can make with 4 bits is equal to 2*2*2*2 = 2^4 = 16.
  Comment on KLaudano's post “If we have 4 bits and eac...”
  (13 votes)
Judepius Ugwuanyi
Posted 3 years ago. Direct link to Judepius Ugwuanyi's post “"At 11:47, what are elect...”
"At
11:47
, what are electromechanical transistors?"
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(6 votes)
Answer
- valeriaacesarr
  Posted 8 months ago. Direct link to valeriaacesarr's post “it focuses on the interac...”
  it focuses on the interaction of electrical and mechanical systems as a whole and how the two systems interact with eachother.
  Button navigates to signup page
  (2 votes)
Brayden Weimholt
Posted 5 months ago. Direct link to Brayden Weimholt's post “How does a computer know ...”
How does a computer know how to display this information?
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(7 votes)
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aniketprasad123
Posted 3 years ago. Direct link to aniketprasad123's post “whenever i see computer s...”
whenever i see computer specification there written
32 bit
64 bit
128 bit

i always wonder what this means
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(3 votes)
Answer
- KLaudano
  Posted 3 years ago. Direct link to KLaudano's post “32 bit and 64 bit refer t...”
  32 bit and 64 bit refer to the addressable memory. A 32 bit computer can only use about 4 GB of RAM, whereas a 64 bit computer can use about 16 exabytes of RAM. 64 bit computers can often do more calculations per second, so they are faster.
  Comment on KLaudano's post “32 bit and 64 bit refer t...”
  (6 votes)
Jayda skaling
Posted 2 years ago. Direct link to Jayda skaling's post “How do just two numbers m...”
How do just two numbers make up an entire device
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(2 votes)
Answer
- aayushchakro
  Posted 2 years ago. Direct link to aayushchakro's post “Computers can't understan...”
  Computers can't understand statements or requests like "Please put the picture of dogs on the top right page of the screen". For computers, it's total gibberish. The best way for computers to understand our requests are by the most simple types of questions possible - YES or NO. 1's and 0's simply respond to the computer asking "Does variable x = y?". So whatever question the computer asks, we can say YES or NO, 1 or 0. These questions can range from anything from "what is this letter" to "where is this item's coordinates". At the end of the day, computers just run on "should I do this", numerous times.
  Button navigates to signup page
  (6 votes)
kpendley
Posted 5 months ago. Direct link to kpendley's post “what are bits”
what are bits
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- tomiwa.
  Posted a month ago. Direct link to tomiwa.'s post “Bits are binary digits (0...”
  Bits are binary digits (0 and 1)
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Jenny Bao Ngoc
Posted a year ago. Direct link to Jenny Bao Ngoc's post “chả hiểu gì cả”
chả hiểu gì cả
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54918
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why is this topic so complicated and stressful given the fact that i literally just found out about it today?
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Caleb
Posted 3 months ago. Direct link to Caleb's post “why are bits used to repr...”
why are bits used to represent everything?
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(2 votes)
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- tomiwa.
  Posted a month ago. Direct link to tomiwa.'s post “Computers only understand...”
  Computers only understand information when it is in binary or in binary digits (Bits): 0 and 1.
  So all we do is converted to bits so the computer can understand.
  Button navigates to signup page
  (2 votes)