7 Segment Counter using IC 555 and IC 4026

Published  September 5, 2015   63
J Jayant
Author
7 Segment Display Counter using IC 555 Timer IC

Digital counters are needed everywhere in this digital world, and 7 segment display is one the best component to display the numbers. Counters are needed in object/products counters, digital stopwatches, calculators, timers etc. To use the 7 segment with ease, there is a 7 segment driver IC which is IC CD4026, so we are building 7 segment counter circuit using 4026 IC.

 

IC CD4026

4026 IC  is a 4000 series IC. It is a CMOS seven-segment counter IC and can be operated at very low power. It is a decade counter, counts in decimal digits (0-9). It is used to display numbers on seven segment displays and it increment the number by one, when a clock pulse is applied to its PIN 1. Means more the clock pulse rate, faster the numbers change in 7 segment Display. Below is the pin diagram and pin description of 4026 IC:

IC 4016 Pinout

 

Pin number

Name

Description

1

CLK

Clock in, Increment the counter with each Positive clock pulse (LOW to HIGH).

2

CI

Clock inhibit - when low, clock pulses increment the seven-segment. Freezes the counter when HIGH, active HIGH.

3

DE

Display enable- chip will be ON when this pin is HIGH, and OFF if it is LOW.

4

DEO

Display enable out - for chaining 4026s

5

CO

 The CARRY-OUT (Cout) signal completes one cycle every ten CLOCK INPUT cycles and is used to clock the succeeding decade directly in a multi-decade counting chain

6

F

Connected to ‘f’ of the 7 segment.

7

G

Connected to ‘g’ of the 7 segment.

8

VSS

Ground PIN

9

D

Connected to ‘d’ of the 7 segment.

10

A

Connected to ‘a’ of the 7 segment.

11

E

Connected to ‘e’ of the 7 segment.

12

B

Connected to ‘b’ of the 7 segment.

13

C

Connected to ‘c’ of the 7 segment.

14

UCS

Ungated C-segment - an output for the seven-segment's C input which is not affected by the DE input. This output is high unless the count is 2, when it goes low.

15

RST

Reset PIN, active HIGH. Reset the counter to 0 when HIGH.

16

VDD

Power supply PIN

 

Above table explains the function of each pin of IC CD4016 clearly.

 

Seven Segment Display

It consists 8 LEDs, each LED used to illuminate one segment/line of the unit and the 8thLED used to illuminate DOT in 7 segment display. We can refer each line/segment "a,b,c,d,e,f,g" and for dot character we will use "h". There are 10 pins, in which 8 pins are used to refer a,b,c,d,e,f,g and h/dp, the two middle pins are common anode/cathode of all he LEDs.

 

IC 4026 is used to drive common cathode 7 segment display. In common cathode 7 segment display cathodes of all the LEDs are connected together, and all the positive terminals are left alone

seven segment display pin diagram

 

Components

  • 555 timer IC
  • 4026 IC
  • Common cathode 7 segment display
  • Two- push ON, push OFF button.
  • Resistors – 10k (3), 100k
  • Capacitor 1uF, 22uF

 

7 Segment Counter Circuit Diagram & Working Explanation

555 Timer 7 Segment Display Counter Circuit Diagram

Circuit is quite easy and self-explanatory, we have interfaced the 7 segment to the 4026 IC, PIN 4,5,14 are left open as we haven’t used them, PIN 15 used to Reset the counter with the help of a PUSH button Switch. PIN 2 is kept LOW to avoiding the freezing and PIN 13 is kept HIGH to enable the IC.

 

Now, the another main component of this circuit, other than IC4026, is 555 timer IC. 555 timer is used here to provide the clock pulse on each Button Press, whenever we press the button the counter advance by one. 555 Timer IC is used here in Monostable mode, to know more, go through this article 555 Timer Monostable Multivibrator Circuit.

 

We have also used a RC circuit (22uf capacitor and 100k resistor) at CLOCK PIN 1 of 4026, so that it only counts one clock pulse on each time button is pressed. Otherwise circuit may behave unexpectedly OR it can count two or more pulses because of noise or bouncing effect of Push button.

Video

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Comments

Submitted by Red Viaje on Tue, 11/03/2015 - 08:17

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Hi! I built this circuit but when I press the count button, it just goes to 1 and never goes beyond that after pressing it again. And when I press the reset button, it resets to 0 but if I press the count button again it doesn't work anymore. What do you think is the problem? :( Thanks.

Submitted by Harshad Dhane on Thu, 11/12/2015 - 11:32

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My counter is showing 0 only I pressed the buttons nothing happened

The circuit is working perfectly, please double check your circuit connections specially connections to the seven segment display and only use COMMON CATHODE type seven segment. Take the help of bread board circuit Image.

Actually you can use a COMMON ANODE 7-Segment Display but you need to reverse the polarity of the battery and the capacitors or the polarized things in the circuit. I've tried it myself and the circuit works perfectly. Hope it helps..:)

I bought an Anode by mistake (newbie), and i was thinking of reversing, just had to check the comments to see if its possible, and here i found and I want to ask if by reversing, only the ones with polarity right? battery, capacitors but the circuit map/diagram remains the same?

Submitted by steven on Sat, 12/19/2015 - 11:15

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I just made the circuit the 7 segment display turns on but on my design i made just made two holes for the switchs and idk how to play the 4 legged switchss on the board pls help me thank u

Submitted by HTM on Sat, 03/12/2016 - 21:42

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I tried so many times but

1. IC CD4026 becomes hot every time
2. when i press the button no change occur in the display

I checked the connection but everything is ok. what is the problem? plz help me.

* i used 9 V DC Adapter

Submitted by andy mackay on Thu, 07/14/2016 - 00:52

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Hi guys, I have been experimenting with this ic 4026 for a couple of days, and when I finally got it working, the numbers were just spinning around very quickly and just displaying random numbers, I was just using a debounce circuit, and not the 555 as you have here. But what I found was that as soon as a jumper was connected to the same track as pin 1 (the clock pin) the 7 segment display would take of running thru the numbers very quick, even if I just touched the pin 1 with the metal prong of the jumper this was enough to set it going, which I assumed was something to do with capacitance from the bread board, to stop it I used a large value resistor.

Submitted by aasas on Mon, 09/12/2016 - 15:26

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what if i want to use 2 seven segment display?i want to use it as a timer ... in minutes
will this work?

Submitted by Parth doshi on Sat, 10/01/2016 - 17:14

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What if I have to count 2 digit numbers ....and display on 7 segment

Submitted by Venkatesan v on Thu, 11/24/2016 - 20:04

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Sir i need to drive a two 7segments in single ic. I can I do it sir pls tell me

Submitted by suhaib on Tue, 01/03/2017 - 20:13

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I built the circuit correctly but it not working , what is the problem tell to me

Submitted by thesecret2 on Mon, 02/06/2017 - 20:11

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i built the circuit correctly and check the circuit perfectly but it just display 0 when i press the count button it doesnt go up the reset button seems fine. please reply ASAP I really need help. you can help by taking pictures of what u built side by side and front please

Submitted by ahmed on Sun, 02/12/2017 - 06:21

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I have connected the circuit and it works properly , thanks a lot for your help !!

Submitted by Surru on Sun, 03/05/2017 - 20:37

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I want to use 5 digits each with a 7 segment display. Do I need 5 of each of the components? I want a simple push button below each digit to increment from 0-9, no reset required. If I were to use an off the shelf assembled 5 digit display can I integrate just the push button to increament

Submitted by biddi on Tue, 03/21/2017 - 03:14

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my circuit works on Yenka simulation software, but does not work on breadboard. Seven segment is always showing 8 . Does not rest or count

Submitted by James Myers on Mon, 04/03/2017 - 05:26

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I built the circuit as designed and of course it worked perfectly. I then tried to substitute a much larger display (2.24" character height) but it does not work. I assume that is because the original display (.56" with a Vf of 1.8) works well at 9VDC while the larger display has a Vf of 6.8, which will not function at 9VDC. Can you tell me what changes I need to make in the circuit diagram to enable use of the substitute larger display? Thank you for any help you can give me.

Thank you for the E-Mail response to my initial posting.  You asked about the 2.24" character height display that I tried to substitute after successfully building the basic circuit shown above.  This 2nd display is listed as Vf=6.8 @20mA and mcd=30@20mA (I don't know what mcd stands for and it could be critical).  The segment output color is Red.  Your note said "you could try this IC.... with a source current of 6.8mA".  If I understand you correctly, I should add current limiting resistors (10K) on each segment and increase Vdd to 15 VDC.  Does that also mean to continue using the IC4026.  P.S. I've recently found another 2.24" character height display with Vf=2.0 @20mA and mcd=34 @10mA.  Brilliant Red output color.  Thank you for your comments and I hope to hear from you on my latest post.

Submitted by Mário on Thu, 05/18/2017 - 22:44

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tks great circuit!
I like the CD4026 a lot, but what is the use for DEO - Display enable out?

Submitted by JHB on Thu, 06/29/2017 - 08:19

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It was such a lovely circuit. Couldn't get the common cathode display but had to create one with LEDs and it works perfectly when all components used conform with the exact specification, good one guys.

Submitted by yza on Sun, 09/17/2017 - 15:12

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I cant make it work :( the schematic diagram btw. i have been trying i did exactly as it is in you schematic diagram but it really wont work :( please help

Submitted by Catman847 on Sat, 09/30/2017 - 21:21

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circuit is working correctly in simulation but I want to know how to replace button with sensor, my sensor is AD021 3-80cm proximity switch.

Submitted by Catman847 on Sat, 09/30/2017 - 21:21

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circuit is working correctly in simulation but I want to know how to replace button with sensor, my sensor is AD021 3-80cm proximity switch.

Submitted by Andrew Hodson on Tue, 10/31/2017 - 05:30

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Why aren't there resistors from 4026 to 7-segment? Can 1 get ready made PCBs of this circuit?

Submitted by Panduleni on Tue, 11/07/2017 - 02:19

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Can you please provide me with the purposes of the resistors, the capacitors and why of that values?

Submitted by Ahmed Khalaf on Sat, 12/09/2017 - 20:57

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Hi,
Can anyone help me here, am looking for a very simple BCD4026 manual electronic counter circuit that has a buzzer which will be ON when number of manual counts/clicks reaches 10, and the buzzer will stay ON until I hit a reset button. Please, any ideas or schematics around that can d that?

Submitted by Ahmed Khalaf on Tue, 12/12/2017 - 05:53

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Hi,
How can I modify your circuit by adding a Buzzer to make it beeping when you reach number 9 , and it will continue beeping until you click the reset button to stop the buzzer?

Submitted by Islam Salahat on Wed, 03/07/2018 - 00:27

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I have an assignment that I should write a code for a 7 segment with 4 switches input
explain >> 4 switches mean 4 bit X1 X2 X3 X4
assuming X1=1 (switch on)
X2=0 (switch off)
X3=0 ( switch off)
X4=1 (switch on)
that mean input will be (1001) == (9) which mean the 7 segment will display 9
and so on
how can I write this code , (I am so bad at C++ programming and micro C programming )

Submitted by Chris Justice on Thu, 05/24/2018 - 14:43

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The project is good and perfect.

but I have a question....
Apart from ic4026, Is their any other linear ic that is non volatile that is..ability to store last value of the 7 segment when power is of?

with 4026, I must start counting from one any time I turn on, any linear ic that can store the last digit before turn of and display it automatically when turned on?

Submitted by Rattan on Thu, 05/31/2018 - 07:44

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This circuit is working ok but I am facing one problem while cascading another ic after reaching digit 6 it jumps to digit 17 ,18 and count till 26 and again jump to 37 .I mean ic pin 5 generate pulse after 6 instead of 9. Please help me to solve this.thanks tkakur05799at the rate gmail.com

Submitted by Zhafran on Fri, 06/08/2018 - 12:09

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Hello i want to ask something.
Can i make this circuit using a PCB?

What would I have to do to have a self restart counter that counted from 0 to 9 then reset and automatically started counting again from 0 to 9, repeating this cycle continuosly.

Thanx