Logic Gate AND 74HC08

74HC08 AND Logic Gate
ID: #99187363 In stock, 17pcs
6.30 AED
VAT Inc.

The 74HC08N is a quad 2-input AND CMOS Gate which is an elementary building block of a digital circuit. Most logic gates have two inputs and one output. At any given moment, every terminal is in one of the two binary conditions low (0) or high (1), represented by different voltage levels. An AND gate is a digital logic gate with two or more inputs and one output that performs logical conjunction. The output of an AND gate is true only when all of the inputs are true. If one or more of an AND gate's inputs are false, then the output of the AND gate is false. The 74HC08 is identical in pinout to the LS08. The device inputs are compatible with Standard CMOS outputs; with pullup resistors

AND Logic Gate 74HC08 Experiment:

Connect one of the 2-input AND gates (74HC08) as shown in Figure 1. Connect two wires to the A and B inputs of the gate (Pins 1 and 2) and connect these to the 5V rail. Connect the output (Pin 3) to one of the LEDs via a 100 Ohm resistor as illustrated in Figure 1. Remember to connect power to the Vcc and GND terminals of the IC (Pins 14 and 7 respectively). Remember to leave the power supply turned off until you are sure that your circuit is wired correctly. Use the bench supply to give you a 5V fixed supply. Connect some hook-up wires to leads using crocodile clips and plug them into the DC 5V fixed inputs on the bottom right of the bench supply.

The 2-input AND gate starting configuration.

  • Copy the outline truth table below into your logbook. Change the inputs A and B (i.e. 0 and +5V) to obtain all the possible combinations and complete the truth table. Enter both the logical value of the output (0 or 1and the actual voltage measured using a Digital Voltmeter - Measure voltage across the resistor and the diode to get the actual voltage drop between pin 3 and GND. Your multimeter should be set to measure DC voltage (not the ~ AC voltage setting) in the range of 20V (describes the maximum voltage), so rotate the dial on the multimeter until it is in the DC 20V range. Give the exact voltages that you obtained for each state of the gate. Note that, in TTL logic, any voltage above 2.4V is generally classified as logic, and any voltage below 0.8V is generally classified as logic 0. Most of our ICs are either TTL or CMOS.
A B F V (actual voltage)
0 0    
0 1    
1 0    
1 1    

The 2-input AND gate can be extended to a 4-input AND gate as shown below. Connect the gates as shown and generate the values for the truth table below.


Figure 2: A 4-input AND gate, built using 2-input AND gates.



0 0 0 0  
0 0 0 1  
0 0 1 0  
0 0 1 1  
0 1 0 0  
0 1 0 1  
0 1 1 0  
0 1 1 1  
1 0 0 0  
1 0 0 1  
1 0 1 0  
1 0 1 1  
1 1 0 0  
1 1 0 1  
1 1 1 0  
1 1 1 1  

The truth table of AND Logic Gate 74HC08