Download A|B

Electronics Club
Introductory Lecture on Digital Electronics
Why Learn Digital ??





Is it because computers are digital or the
world is going Digital ??
As Samsung says “The new realm of
DigitAll Technology”
One to One functions
Virtually immune to noise
Easy to rectify mistakes ( Why?? )
What is Digital Electronics??

A Digital circuit is based on a number of discrete
voltage levels, as distinct from an analog circuit that
uses continuous voltages to represent variables
directly.

In most cases the number of states is two, and these
states are represented by two voltage levels: one near
to zero volts and one at a higher level depending on
the supply voltage in use.

These 2 discrete states might be called “Low” and
“High”, 1 or 0 , True or False.

Simple intuitive Boolean algebra !!!!
Wanna See Noise Immunity !!
Technology Low Level High Level Supply
Voltage
CMOS
0 to Vcc/2 Vcc/2 to Vcc Vcc = 5V
TTL
0 to 0.8V
2V to Vcc
Vcc = 5V
What is common to Digital Circuits??


Supply Voltage  5V (at the club )
A term called CLOCK
Will you change
Mr. Clock
Says :
Mr. Logical One
Yes Sir !!
Right away
Mr. Logical One
Responds:
In Electronics Terms

A clock is simply a square wave , which is
mostly common to all components put in a
digital circuit. We may classify it as a
parameter in measuring speed of the circuit.
A Logical One
5V
0V
A Logical Zero
The Binary Number System
Representing Nos. as a sequence of
1’s and 0’s.
 Nos. in Base 2
 Decimal to Binary Conversion
 Binary to Decimal Conversion
 Intuitivism here too!!!!

Logic Gates

Simple Boolean functions
AND
 OR
 NOT
 XOR
 NAND
 NOR

AND Gate
Input 1(A)
Output (Y)
Input 2(B)
Input 1 Input 2 Output
Y=A& B
0
0
0
0
1
0
1
0
0
1
1
1
OR Gate
Input 1 (A)
Output (Y)
Input 2 (B)
Y=A| B
Input 1
Input 2
Output
0
0
0
0
1
1
1
0
1
1
1
1
NOT Gate
Input A
Y = ~A
Output Y
Input
Output
1
0
0
1
XOR NOR NAND XNOR Gates
A
B
A XOR B
A
B
~(A&B)
0
0
0
0
0
1
0
1
1
0
1
1
1
0
1
1
0
1
1
1
0
1
1
0
A
B
~(A|B)
A
B
A XNOR B
0
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
0
1
1
0
1
1
1
Dear Transistor

Most simple use as a switch
Supply
Load Device
Input
You did not understand
something ???
Read the handout
 Even better come to the workshop
 Lets work One to One 


Register for the workshop

Finally Be there !!!!
Thank You