Digital Stop Watch

jacky November 10, 2011 69 Comments

Make a Digital Stop Watch

Description

A digital stop watch built around timer IC LM555 and 4-digit counter IC MM74C926 with multiplexed 7-segment LED display. MM74C926 consists of a 4-digit counter, an internal output latch, npn output sourcing drivers for common cathode, 7-segment display and an internal multiplexing circuitry with four multiplexing outputs. The counter advances on negative edge of the clock. The clock is generated by timer IC LM555. The circuit works off a 5V power supply. It can be easily assembled on a general-purpose PCB. Enclose the circuit in a metal box with provisions for four 7-segment displays, rotary switch S1, start/stop switch S2 and reset switch S3

Testing

First, reset the circuit by pressing S3 so that the display shows ‘0000.’ Now open switch S2 for the stop watch to start counting the time. If you want to stop the clock, close S2. Rotary switch S1 is used to select the different time periods at the output of the astable multivibrator (IC1).

Digital Timer Circuit Diagram .

Digital Timer Circuit

You may also be interested in other Timer circuits we have in our website:

1. Long Duration Timer Circuit

For more circuits, please check our category on Clocking and Timer Circuits

Tags: 555 timer, circuit design, circuit diagram, Electronic Circuits, timer circuit

Categories:

Clocking & Timer Circuits

Comments

john muqattash
April 19, 2015

Hi guys i built the circuit successfully however it doesnt reset at 60 senconds and instead continues to 99 does anyone have any soulutions

- Emmanuel M. Bauyon
  January 31, 2018
  
  yeah. thesame as mine I dont know what to do to reset at 60 seconds. do you know the solution?
  
john muqattash
March 17, 2015

Hi i have built this circuit for testing purposes, however i find that the teansistors connnected to the 7 segment displays overheat alot and the 7 segment displays do not light up properly do u have any suggestions for the problems and any solutions? Thanks

Umesh
March 11, 2015

How much cost of digital stop watch circuit

durga prasad
January 21, 2015

hi sir,
can i know which ic can be used to replace 74C926? Also can i know how resistors are connected to the 7 segment display?

arun
September 16, 2014

i am also engineer of ETC….its great informative site…..good job..

Arati
July 10, 2014

If any use of RTOS system in electronics industry. Please tell me.

Mark Odyssey Rodel
April 17, 2014

After making the circuit we encounter some problems, instead of just counting from 0-59 it continuous up to 99. Any idea how to fix this.

poonam
March 20, 2014

i want pcb design.please send it

- poonam
  March 20, 2014
  
  what can i use as a replacemeent for MM74C926
  
iksir
January 9, 2014

you know what, I’ve done with this by using 74C926. But, it’s just counting. When it’s 00.59, it just continue counting til 99. it should be 01.00 if it’s a stopwatch as you wrote at the title.
do you know how to fix it?

digit
October 31, 2013

what can i use as a replacement for MM74C926??

- Seetharaman
  November 1, 2013
  
  It is a special purpose custom made IC has no replacement equivalent.
  
wall plugs - Page 2 - FlyerTalk Forums
October 15, 2013

[…] Or maybe this one: http://www.electronicecircuits.com/e…nd-programming Or pin 3 on the LM555: http://www.circuitstoday.com/digital-stop-watch Or the 4MHz crystal needed here: http://www.electronics-project-desig…TimeClock.html Or Y1, […]

yashu
October 9, 2013

Wat will be the cost of tis project..!

Johary Ambalagan
October 5, 2013

…were finally finished this project!!! but the IC is so expensive-

- Mohsin
  November 15, 2014
  
  Bro does this project really work?
  
sunilnadh
September 30, 2013

IN OUR TO SUBMITT A MINI PROJECT I HAVE SELECTED THIS ONE
PLS wish me to get success

Renuka B. Khatke
July 16, 2013

What will be the price of overall project.

Nedugod
May 30, 2013

Can i use Mm74C928 instead of 926

chandan
April 7, 2013

can you mail me the pcb layout

chandan
April 7, 2013

can you mail the lay pcb layout

bharti
March 17, 2013

we dont get the ic mm74c926 let we know there is any replacement for it

shalaka
March 17, 2013

we dont get the ic mm74c926 let we know there is any replacement for it

remiz
March 6, 2013

i would like to know how this circuit works????? anyone help me plzz

MA
February 24, 2013

How are the resistors connected to the 7-segments ?

- Madhu
  September 2, 2013
  
  7-segment display as 7 terminal, no 15 port of the IC is connected to the “a” terminal of the 7-segment display through resistor. Like that all the terminals of the IC is connected to the respective terminals of the 7-segment display. TO know more about the terminals of the 7-segment display check this link http://en.wikipedia.org/wiki/Seven-segment_display.
  
lim
February 6, 2013

what is the alternative ic for 74C926?

- rameez
  March 18, 2013
  
  lim did u get the alternative??
  
zaini
November 18, 2012

i’m done doing this stopwatch..but can’t operatingw well…the problem is cannot start….when reset,the LED show a number 8888…so what is the problem?

parinay
October 28, 2012

sir ,how we can assemble these project if we don’t know d procedure .so ,plz rply soon i wanna to module these……

zaini
October 23, 2012

how to make large size stopwatch?

Siddheshwar
October 12, 2012

sir is there any replacement for ic mm74c926?

bharath4
October 5, 2012

hi can i use any other ic’s instead of mm74c926.if there any plz reply me…….

Aditya
August 23, 2012

HI!!
i’m makein this ckt on EAGLE.
but m not understanding which switches to use.
plz can you help me?

din
July 5, 2012

hi, i am student of unikl miat located at sepang .. i learning mechanical and currently doing my fyp that need automatic digital timer or stopwatch. i really do have almost zero skill and knowledge obout this item. if u may .. could u pls elaborate this device for me . tq
ur help are highly appreciated .

Faisal
June 15, 2012

HITEC UNIVERSITY STUDENT:I have Made digital stopwatch using this cct . and it is working properly.the problem is that IC2 is expensive (Rs 800) and its not available easily in market.you can use any seven segment display but it should be common cathode. its above 3rd pin should be ground.2 pole 4 position rotary switch should be used pole is connected with 22k resistor and other any two terminals with position 1 and 2.disp1 in this cct of milli sec disp2 is sec disp3 is minute.ground should be given properly use small wires as you can for breadboard.

- zaini
  November 18, 2012
  
  buy from me.so how?
  
- Usman
  July 9, 2014
  
  RIPHAH INTERNATIONAL UNIVERSITY STUDENT:
  AOA. i am using proteus to design the stopwatch. Can u tell me which tansistor to use? The bc547 bipolar or the NPN.
  Also from where did u buy the IC? I am assuming you are living in the Isl/Pindi region.
  Also how do I connect the 7 segment displays with each other?
  Plz reply soon
  
sruthi
May 25, 2012

pls tell me the applications of the chip used.how we can expand this project?

sruthi
May 25, 2012

plaese send me the required functions of the chip IC1 LM555,and IC2 MM 74C926.PLEASE INCLUDE WHY THE CAPACITANCE ARE IMPORTANT IN THIS CIRCUIT.

ashraf
May 10, 2012

i have made this circuit but its not counting..its showing 0000 reading but not counting..
please help me

Paul
May 3, 2012

T1 is not listed on the parts list and T2 is there a suitable sub for this part? The 7 segment displays need pinout connections. Also part# for the 7 segment displays can’t be found is there a sub for this also. Thanks

rutuja
April 16, 2012

plz snd the question for oral exam on interval measurement using 74c926

rutuja
April 16, 2012

Plz snd the questions and answers of project on internal measurement using 74c926(digital stop watch)which will be asked for oral examination as early as possible.

seetharaman
November 4, 2011

Hi Naish use the following data for your connections
http://www.datasheetcatalog.org/datasheet/hp/HDSP-5507.pdf

NAISH
November 2, 2011

i m not finding hw to cofigurate resistor with sevensegment…plz help me..

asichi
August 15, 2011

okey..thank you very for responding..!!..

seetharaman
August 13, 2011

Hi Asichi MM74C926 is an LSI with lots of digital circuits integrated into it. with discrete 741s you cannot build up the required circuit.

asichi
August 12, 2011

instead of using 74c926… can i use 74ls series of ic.??
if yes,.what type of 74ls can i use.?

Reques
June 5, 2011

Dear Friends,
It is humbly requested that please show your any contact or email espacially email of gmail account becasue my email id is also in gmail so we can contact easily.

Email salmanwaheed2008@gmail.com

thanks.

pinky
April 7, 2011

i have made this circuit but its not counting..its showing 0000 reading but not counting..plus the 555timer is not working with LED but its absolutely okay
plz help

virendra
February 21, 2011

i want pcb design of digital stopwatch.please send me.

Marcello
January 2, 2011

I cant find mm74c926 in multisim too. what can i use instead of it ??
Thanks

xeeshan
November 27, 2010

sir, plz send me more details of itz component and a fine circuit plzz i will be vry thankful to u sir….

Leary
September 23, 2010

Please send me the pcb layout. tnx

rashmi
September 3, 2010

i wanted the digital stop watch uing bcd’s and simple circuits

sally
June 30, 2010

i have to make it on multisim but i cant find mm74c926 in multi. what can i use instead of it ??

- Mohsin
  November 11, 2014
  
  I am also trying to do so.. have you done??
  
MARK ANGELO
October 8, 2009

oh man… this circuit saved me from my subject,it really worked, and it impressed my instructor..

it has two functions… the regular stopwatch and the split type.

though the ic 74c926 type is expensive.

i have pics on my facebook account of this project.

- vitu
  August 10, 2012
  
  i couldnt get ic 74c926.is there any alternative…
  
ankush
September 18, 2009

piease send the good circuits to my email id

cesar peralta
April 16, 2009

RESET PROBLEM: why won’t it reset when the timer is on stop mode?

joseph aranas
April 10, 2009

sir, i tried this circuit of yours digital stop watch, and it works fine….thing is the hundredth of a second works, but when it comes in the minute counting, it doesn’t stop at 60 but goes to 99…what to do…please help…thanks

Jaitun
November 17, 2008

I want to khnow scope of digital stopwatch.

vivek
October 12, 2008

i want detail info about project. pls help

phanindra
August 23, 2008

how can digital stop watch works it is a MM74C926 decade coUnter IC how it could count i me to say a digital stop watch will count 60sec and then reset.

chumisa
April 27, 2008

since a 74C926 counter is not there when simulating the circuit for the stopwatch, can a up/ down counter be used instead of this one? or which counter can be used?

dumudu
March 10, 2008

please send me the pcb of led drivers

Digital Stop Watch

Make a Digital Stop Watch

Description

Testing

Digital Timer Circuit Diagram .

You may also like:

We recommend:

Comments

Leave a Reply to MA Cancel reply

Sort By Type

Other Links

PCBFox