Simple Digital Stopwatch Circuit


BySaddam 58

Digital Stopwatch Circuit using IC 555

Often we need stopwatch to differentiate the time of two events. Here in this tutorial we are going to design a simple digital stopwatch circuit, without using any microcontroller. Here we have used the popular 555 timer IC, CD4033 ICs and few other components, which are listed below.


Required Components

  • IC 4033 - 2
  • 555 timer IC -1
  • Common Cathode 7 Segment Display -2
  • 150 Ohm -1
  • 100K resistor -1
  • 33K resistor -1
  • 56K resistor -1
  • 10uF capacitor -1
  • On/off switch -1
  • Push button  -1
  • Bread board -1
  • 9 Volt Battery -1
  • Battery Connector -1
  • LED -1
  • Voltage Regulator 7805 -1
  • Connecting wires


IC CD4033

This is counter and seven segment decoding in one package IC which is very easy to interface with seven segment displays. This is fully static counter operational IC and ideal for low power displays. This IC can be used for decade counting seven segment decimal displays, frequency division seven segment decimal displays, clocks, watches, timers, counter/display driver for meter applications.

IC 4033


Digital Stopwatch Circuit Diagram and Explanation

In this circuit we have used a 555 timer IC based astable multi-vibrator which is for creating 1 second delay. And two common cathode seven segment decoder IC’s namely CD4033. The output of astable multivibrator is directly applied to seven segment decoder IC’s (U4) Clock pin (1) and carry output pin(5) of U4 IC is directly connected to clock pin (1) of second seven segment decoder(U3). And two seven segment are connected with these decoder (U3 and U4). Its connections are shown in stopwatch circuit diagram given below. One push button is used to stop /start the stopwatch and one push button is used to reset the stopwatch. A 5 volt voltage regulator is used for providing 5 volt to whole circuit. And a 9 volt battery is used for powering the circuit.  Rest of connections are shown in the circuit diagram.

Digital Stopwatch Circuit Diagram



In this stop watch circuit we have generated one second delay by using 555 timer based astable multivibrator. By using some calculation we can easily generates one second delay. In astable multivibrator there is two resisters and one capacitor is responsible for delay by charging or discharging capacitor through resistors. Calculation formula for generating delay for astable multivibrator is given below.

F=1/T= 1.44/(R1 + 2R2) C1

In this project we have selects R1 is 33K, R2 is 56K and C1 is 10uF. [Also check: 1 minute timer circuit]

Ass Astable multi-vibrator generates one seconds delay, this delay is oscillations or pulse of 0 and 1. So we will use this pulse for triggering the seven segment decoder then seven segment decoder changes the digit number with the one second of time period.

Digital Stopwatch Block Diagram

When we ON the stopwatch (by start/stop button) it start counting from zero and if we turned OFF the same button then counting is stop or pause until again turned ON the same button or press reset button.

There are two seven segments, so this stopwatch circuit can count 00-99 seconds time. 


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  • daniel's picture
    Sep 20, 2015

    do you have pcb layout for this circuit.?

  • Jayant's picture
    Oct 06, 2015

    There are lot of online Tools and softwares available, which convert schematic into PCB layout like Fritzing, you can design a good PCB layout using those.

  • NB's picture
    Nov 01, 2015

    Is there any IC available that can replace 4033 and similarly for 7805?

  • Abhishek's picture
    Nov 03, 2015

    You can use 4026 (Check this) in place of 4033. And you can remove 7805 and connect 9v battery directly, otherwise there are lot of voltage regulators available.

  • Hasan Tanweer's picture
    Hasan Tanweer
    Dec 12, 2015

    What will be the changes in circuit connections , , if I use common anode 7 segment display instead of common cathode ?

  • Abhishek's picture
    Dec 17, 2015

    Then you need to use Common anode 7 segment display driver IC like IC7446, instead of 4033.

  • kamulegeya sulaiman's picture
    kamulegeya sulaiman
    Feb 03, 2016

    if i am to use the 4026 instead of 4033.. instead of connecting to rbi, i connect to DEI? thats all that changes? pliz help

  • Ajay's picture
    Feb 08, 2016

    yes, you can connect DE (not DEI) to Vcc like RBI, which is connected to HIGH in 4033. Leave DEO open in 4026 like RBO in 4033.

  • Rick's picture
    Feb 16, 2016

    Can this circuit me modified to count manually with each push of the switch.

  • Nachi Kumar's picture
    Nachi Kumar
    Mar 16, 2016

    Don't forget to ground the 14 pins on both the 4033s. It will work perfectly.

  • Indrasish's picture
    May 05, 2018

    I've done that ..but still it's not working

  • muggle's picture
    Apr 21, 2016


    I am trying to extend this circuit to an activity tracker and save it to an SD card. Can this circuit be modified for that?

  • Tarek's picture
    Apr 28, 2016

    Can anyone tell me how to make the second 7 segment display count only till 5?!

    thank you.

  • Mike's picture
    May 04, 2016

    My output stuck at 68 its not working please help!

  • Tarek's picture
    May 27, 2016

    How can i show the hidden pins VDD/VSS in 4033 ??

  • REyhan's picture
    Jun 04, 2016

    How can i show the hidden pins VDD/VSS in 4033 ?? my project error if VDD And VSS gone :D

  • mayur patil's picture
    mayur patil
    Sep 01, 2016

    I want PCB layout for this ckt diagram

  • mayur patil's picture
    mayur patil
    Sep 01, 2016

    I want to be ckt diagram plz send

  • niki's picture
    Oct 16, 2016

    is there any equivalent ic for ic4033

  • Maddy's picture
    Oct 27, 2016

    Please read all the previous comments before asking questions, we might have answered them already.

  • kyra's picture
    Oct 17, 2016

    hi sir is there any suggestion of new feature to add in this circuit?

  • afrasiab's picture
    Nov 16, 2016

    i tried with both 4033 and 4026 IC's but circuit don't run

  • habib's picture
    Dec 01, 2016

    which resistor you used in both common point of 7 segment cathode display . you didn,t mention that .pls help may be reason to work my circuit . otherwise everything right ..

  • Maddy's picture
    Mar 04, 2017

    @afrasiab @habib Try grounding the 14th pin of 4033.

  • Oliur 's picture
    Mar 01, 2017

    Has anyone produced an working pcb design?

  • rakib noor's picture
    rakib noor
    Mar 11, 2017

    If i use common anode seven segment decoder here then what i have to do? please,help me

  • sukumar's picture
    Mar 12, 2017

    i want pcb layout for these circuit .CAN u tell any online tool?

  • Engr_Ad_Star's picture
    May 27, 2017

    I real like this site

  • dhawal's picture
    Jul 31, 2017

    what changes i need to do if i use IC 4026 insteed of IC 4033 please help me

  • Danial Ahmed's picture
    Danial Ahmed
    Oct 06, 2017

    Can you upload the proteus project file? I am not able to unhide VSS and VDD pins i tried following the tutorial you posted earlier in comment section

  • Zayn's picture
    Oct 06, 2017

    Sir, i connected tye circuit as shown in circuit but all the lcds on 7 segment glow at same time making "8" and keep on blinking.

  • walther's picture
    Oct 11, 2017

    what if I got common anode LED??
    what IC should i use?? 4026 or 4033??

  • Avinash Verma's picture
    Avinash Verma
    Oct 23, 2017

    i am having a doubt regarding the your connections....
    if we connect according to the circuit diagram, what you have given in the site....
    is it working????
    i have connected according to it but i am unable to get the output.......
    i have checked it trice....
    please help me in that regard....please......

  • juan karlo's picture
    juan karlo
    Nov 30, 2017

    how can i set it at a countdown from 10-0?

  • Arzam's picture
    Dec 02, 2017

    Juan Karlo if you want a countdown circuit then you should create it by your self using combination of D flip flops and decoder. the flip flops will start like the circuit above from 0 to 9 i.e a counter circuit the change will you make will be in the decoder who will display 9 for 0, 8 for 1 and so on. That is it will decode in opposite manner to the circuit above.

  • Jame Ahmed's picture
    Jame Ahmed
    Dec 08, 2017

    What should i need to type to find ic 4033 in multisim. Is there any alternative ic instead of 4033?

  • Haseeb's picture
    Jan 06, 2018

    sir all the connection are perfect but circuit is not working.. Common cathode seven segment is remain on 0 0... i have try it many time but still not working

  • Raja Dasrath kumar's picture
    Raja Dasrath kumar
    Feb 24, 2018

    hi can you make a video full clearly of digital stopwatch to me i have doubt in video that's why i can't understand how element connected with each other

  • markuz's picture
    Mar 11, 2018

    i build this but my reset button reset to 1 instead of 0 how to fix it

  • Steve's picture
    Apr 06, 2018

    Can anyone tell me how can I get 10milisecond in stead of 1second?

  • ali  's picture
    Apr 17, 2018

    can it be resumed after stopping

  • Arslan's picture
    May 02, 2018

    I connect this circuit as given above but its not working.. means it just turn on the seven segment but never start counting....

  • Indrasish's picture
    May 05, 2018

    Made the same circuit , but the seven segment never starts counting. What should I do?

  • usama ali's picture
    usama ali
    Jun 03, 2018

    is there a step by step tutorial available for making this circuit please i need it very badly

  • mehdi's picture
    Jul 10, 2018

    which resistor I will use in the replacement of 33k resister kindly guide

  • sunsuen's picture
    Jul 27, 2018

    i am having a doubt regarding the your connections....
    if we connect according to the circuit diagram, what you have given in the site....
    is it working????
    i have connected according to it but i am unable to get the output.......
    i have checked it trice....
    please help me in that regard....please......

  • Ahmed Samy's picture
    Ahmed Samy
    Aug 02, 2018

    I want you helping me to connect this circuit on bread board with photos and steps

  • Vaibhav's picture
    Aug 27, 2018

    I have tried this circuit more than 5 time. But I am not getting correct out put .

  • Aswinth Raj's picture
    Aswinth Raj
    Aug 29, 2018

    Debugging is very important skill to get any circuit to work.

    What problem are you facing? 

  • Iftiaz Ahmed's picture
    Iftiaz Ahmed
    Sep 03, 2018

    connect 14no. pin with 15no. pin of the 1st IC 4033

  • Iftiaz Ahmed's picture
    Iftiaz Ahmed
    Sep 03, 2018

    In the first 4033 IC, connect the 15pin with 14pin........if the problem is not solved then connect 14pin of each 4033 ic to ground

    N.B - make sure your reset button is connected perfectly...!

  • Ryou's picture
    Nov 20, 2019

    Is it ok to put a resistors in each pin of the seven segment so that the current will not direct flow in the segment?

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