Construction Of Digital Stopwatch With Hourly Alarm System

A stopwatch is fundamentally used for measuring time, but it may also be used to control a device designed to work according to time such as an alarm clock and a time bomb. Stopwatch may be analogue or digital. The analogue uses a fixed numbered dial and moving hands to indicate time. It also has a scale of 60 minutes as well as 60 seconds. A digital clock is “ an electronic device” which “ generates a repetitive series of pulses, known as clock pulses, whose frequency is accurately controlled”

THEORETICAL LAYOUT
In this digital representation, quantities are represented by symbols called digits which may be any of the numbers from 0 to 9. The most common number systems used in digital technology are the decimal, octal, hexadecimal and binary systems. The octal number system is the base-8 system which consists of eight possible digits:0,1,2,3,4,5,6,7. Each digit of an octal number can have any value from 0 to 7. The octal number system is often used in digital computer work. The hexadecimal number system, called the base-16 system, is composed of 0 through 9 plus letters A, B, C, D, E and F as its 16 digits. Here the digits A through F correspond to the decimal values 10 through 15 . One very interesting feature of all the number systems is that they are one to another. The decimal system, also called the base-10 system has evolved naturally as a result of the fact that people have ten fingers. In fact, the word “digit” is derived from the Latin word “finger”. This number system, used by people every day is the most familiar and consists of 10 numerals which are 0,1,2,3,4,5,6,7,8 and 9. Using these symbols as digits of a number,quantities of any form can be expressed. In the binary system, the only two symbols or digits are 0 and 1. This is, therefore, called the base-2 system and can be used to represent any quantity that can be represented in the other number systems. However,

circuit Diagram
it takes a greater number of binary digits to express a given quantity. For example, the number 4 in the decimal, octal and hexadecimal system has 100, 100 and 0100 !