Download Basic Logic Gates

Basic Logic Gates
ECET 111
NAME ___________________
COMPONENTS
 Breadboard
 Wire
 LED
 330 ohm and 1k ohm Resistor
 7400, 7402, 7404, 7408 and 7432
OBJECTIVE
 Under stand the operation AND, OR, NAND, NOR and NOT gates.
 Create a small logic probe.
 Create a simple switched input.
 Under stand the use of combinational logic and how to generate Boolean
equations.
CONSTRUCTION AND TESTING
1. A simple logic probe can be created by using an inverter, resistor and light
emitting diode (LED). Construct the circuit below and test the simple logic
probe.
Note: Keep this circuit if you do not have a logic probe.
1a. Enter the above circuit into Multisim and simulate circuit. Print out the circuit and
attach to lab report.
2. A simple switch circuit can be used to simulate an input(s). Construct the circuit
below and test the output with a logic probe. Check the output using the logic
probe you constructed in PART 1.
Note: Using a switch to simulate the input to a logic gate is optional in our
experiments. The resistor in the switch circuit is used for current limiting purpose.
This current limiting is not required for TTL devices so a simple wire from VCC or
GRND can be used to input a 0 or 1 to your circuit.
3. Construct the following AND gate circuit. Test the circuit and fill in the
corresponding truth table.
A
B
X
What will be the Boolean equation at X?
2. Construct the following OR gate circuit. Test the circuit and fill in the
corresponding truth table.
A
What will be the Boolean equation at X?
B
X
3. Construct the following NOT gate circuit. Test the circuit and fill in the
corresponding truth table.
A
Y
Z
What will be the Boolean equation at Y and Z?
4. Construct the following NAND gate circuit. Test the circuit and fill in the
corresponding truth table.
A
B
X
What will be the Boolean equation at X?
5. Construct the following NOR gate circuit. Test the circuit and fill in the
corresponding truth table.
A
What will be the Boolean equation at X?
B
X
6. Construct the following Combinational Logic circuit. Test the circuit and fill in
the corresponding truth table. (Instructor signature needed)
A
B
C
X
What will be the Boolean equation at X? Identify the Boolean equation at each
point in the circuit.
QUESTONS
1.
Explain the operation of a AND, OR and NOT gate in words only.
2.
What are the three basic logic gates? Why are they called the three basic logic
gates?
3.
Where is Pin 1 located on an integrated circuit (IC)?
4.
Create the schematic for the following Boolean equations.
_
Z= (AB+C)C + A
5.
Using only a 7408, show how you could construct a 4 input AND gate.