This document describes a simple combination lock circuit that uses XOR gates to compare a 4-bit entered code to a stored key code. If the bits match, a green "Go" LED lights up, and if they do not match, a red "No Go" LED lights up. The circuit includes XOR gates, NOR gates, switches to enter the code, LEDs, resistors, and a pushbutton to submit the code for comparison.

1. Name
Muhammad Saeed
Roll NO:14093122-026

2. Topic:-
Simple combination Lock

3. Simple combination Lock
•A simple combination lock is a type of locking
device in which a sequence of numbers is used
to open the lock.

4. SCHEMATIC DIAGRAM
Go LED
Not Go
LED
Key
code
Entered code

5. PARTS AND MATERIALS
• 3 NOR gate
• 4 XOR gate
• Eight switches
• Two light-emitting diodes
• 10 kΩ resistors, 470 Ω resistors
• Pushbutton switch, normally open
• Two batteries

6. Working:-
• This circuit illustrates the use of XOR (Exclusive-OR) gates as bit
comparators.
• Four of these XOR gates compare the respective bits of two 4-bit
binary numbers, each number “entered” into the circuit via a set of
switches.
• If the two numbers match, bit for bit, the green “Go” LED will light up
when the “Enter” pushbutton switch is pressed.
• If the two numbers do not exactly match, the red “No go” LED will
light up when the “Enter” pushbutton is pressed.

7. When we apply Right code:
Go LED
will ON

8. When we apply wrong code:
Not Go LED
will on