## Monday, April 4, 2011

### STUDY OF BASIC DIGITAL ICS

STUDY OF BASIC DIGITAL ICS

AIM:

To verify the truth table of basic digital ICs of AND, OR, NOT, NAND, NOR, EX-OR gates.

APPARATUS REQUIRED:

 S.No Name of the Apparatus Range Quantity 1. Digital IC trainer kit 1 2. AND gate IC 7408 1 3. OR gate IC 7432 1 4. NOT gate IC 7404 1 5. NAND gate IC 7400 1 6. NOR gate IC 7402 1 7. EX-OR gate IC 7486 1 8. Connecting wires As required

THEORY:

1. AND gate:

An AND gate is the physical realization of logical multiplication operation.  It is an electronic circuit which generates an output signal of ‘1’ only if all the input signals are ‘1’.

1. OR gate:

An OR gate is the physical realization of the logical addition operation.  It is an electronic circuit which generates an output signal of ‘1’ if any of the input signal is ‘1’.

1. NOT gate:

A NOT gate is the physical realization of the complementation operation.  It is an electronic circuit which generates an output signal which is the reverse of the input signal.  A NOT gate is also known as an inverter because it inverts the input.

1. NAND gate:

A NAND gate is a complemented AND gate.  The output of the NAND gate will be ‘0’ if all the input signals are ‘1’ and will be ‘1’ if any one of the input signal is ‘0’.

1. NOR gate:

A NOR gate is a complemented OR gate.  The output of the OR gate will be ‘1’ if all the inputs are ‘0’ and will be ‘0’ if any one of the input signal is ‘1’.

1. EX-OR gate:

An Ex-OR gate performs the following Boolean function,

A  B = ( A . B’ ) + ( A’ . B )

It is similar to OR gate but excludes the combination of both A and B being equal to one.  The exclusive OR is  a function that give an output signal ‘0’ when the two input signals are equal either ‘0’ or ‘1’.

PROCEDURE:

1.  Connections are given as per the circuit diagram
1. For all the ICs 7th  pin is grounded and 14th pin is given +5 V supply.
2. Apply the inputs and verify the truth table for all gates.

AND GATE

LOGIC DIAGRAM:

PIN DIAGRAM OF IC 7408 :

CIRCUIT DIAGRAM:

TRUTH TABLE:

 S.No INPUT OUTPUT A B Y = A . B 1. 0 0 0 2. 0 1 0 3. 1 0 0 4. 1 1 1

OR  GATE

LOGIC DIAGRAM:

PIN DIAGRAM OF IC 7432 :

CIRCUIT DIAGRAM:

TRUTH TABLE:

 S.No INPUT OUTPUT A B Y = A + B 1. 0 0 0 2. 0 1 1 3. 1 0 1 4. 1 1 1

NOT GATE

LOGIC DIAGRAM:

PIN DIAGRAM OF IC 7404 :

CIRCUIT DIAGRAM:

TRUTH TABLE:

 S.No INPUT OUTPUT A Y = A’ 1. 0 1 2. 1 0

NAND GATE

LOGIC DIAGRAM:

PIN DIAGRAM OF IC 7400 :

CIRCUIT DIARAM:

TRUTH TABLE:

 S.No INPUT OUTPUT A B Y = (A. B)’ 1. 0 0 1 2. 0 1 1 3. 1 0 1 4. 1 1 0

NOR GATE

LOGIC DIAGRAM:

PIN DIAGRAM OF IC 7402 :

CIRCUIT DIAGRAM:

TRUTH TABLE:

 S.No INPUT OUTPUT A B Y = (A + B)’ 1. 0 0 1 2. 0 1 0 3. 1 0 0 4. 1 1 0

EX-OR GATE

LOGIC DIAGRAM

PIN DIAGRAM OF IC 7486:

CIRCUIT DIAGRAM:

TRUTH TABLE:

 S.No INPUT OUTPUT A B Y = A  B 1. 0 0 0 2. 0 1 1 3. 1 0 1 4. 1 1 0

RESULT:

The truth table of all the basic digital ICs were verified.