tN/ Lq t /'/o
trq't'Ln
Fre t ruu
F iq /j\
rrol 5
F'Q G
p/"F'q a
'1
t (ur F iq
+\1
r
q
Experiment No. 3
LOGIC IiATES
I" Obiectives:
1. To determine experimentally the operation of a NOT (inverter), OR, AND, and
Exclusive OR (XOR) gates.
2. To demonstrate how, using NOT gates, an OR gate can be made to function as a
NOR gate and an AND gate.
3. To demonstrate how, using NOT gates, an AND gate can be made to function as a
NA1YD gate and an 0R gate.
4" To demonstrate how, using NOT gate, an XOR gate can be made to funetion as an
XNOR gate.
II. Materials/Eq uipmentlTools :
Supply voltage, Breadbnard, connecting wires
LED: red or green
Resistor: 150f)
Quad 2-input OR gates {7432)
Quad 2-input AND gates (7408)
Quad 2-input XOR gates {7486)
Hex inverters (7404)
III.Basic Concepts:
Logic gate is a circuit with one or more input signals trut only one output
signal. Gates are digital (two-state) circuits because the input and nutput signals are
either low or high oniy.
An inverter or NOT gate is a gate with only one input signal and one output
signal" The output is always the opposite of the input.
HOT
A can be A' (can tre represented try any variatrle, that is, A: Y) so output
expression is :
Y:A
nA
**
