Two Digit Counter Circuit using 7 Segment and IC 4026

two-2-digit-counter-circuit-7-segment-ic-4026

Two digit Counter Circuit can be seen in hospitals, banks etc for the purpose of counting any process. You might have seen the Single Digit Counter Circuit using 7 segment in our site and this is just an expanded version of the single digit counter. Here we are employing two 7 segments and two IC 4026 a seven segment Display Decade counter. And a IC 555 to feed the required pulse to the decade IC’s used in the above circuit. The whole circuit was designed to increment the count with a single push button switch. Lets move into the working of this counter circuit.

CIRCUIT DIAGRAM:

two-digit-counter-circuit-ic-4026-555

WORKING OF TWO DIGIT COUNTER CIRCUIT:

The working of the above circuit starts with the 555 where it was wired as a monostable Multivibrator. The important characterstics of a Monostable Multivibrator is as long as the pin 2 receives a positive trigger the output at pin 3 will be of low state. And when negative trigger was fed into the pin 2, the output at the pin 3 will go high for a specific period of time. This time was decided by the Resistor R2 and Capacitor C2 connected along with it. This timing is necessary to offer the debouncing delay to the circuit in order to avoid multiple input pulses at the same time to the trigger input. The equation governing the time period is given by T= 1.1 x R x C.

pin-diagram-IC-CD4026

IC 4026 is a seven segment display decade counter which is used to drive a 7 segment display with input clock pulse. Here the clock pulse was obtained from the monostable multivibrator and fed into the pin 1 of the IC2 4026 since count value should be started from the 7 segment which is placed right hand side. Pin 2 was usually grounded since giving high signal to this pin will inhibit the input clock signal to pin 1. Pin 3 was meant for enabling the display and it was given high signal in both of the 4026 IC’s. The 4th pin was meant for enabling carry out and we left this pin unconnected and the same case applies to pin 14th of the 4026 IC.

Initially when the circuit is switched ON the 7 segments will indicate “00” count and as soon as the negative trigger was given to 555 high pulse will be obtained from pin 3. The high pulse was fed to  IC2 and therefore it increments its count with each button press displaying 1,2,….9 in its seven segment. As soon as 10 counts was incremented by IC2 a high to low signal was obtained from its pin 5 which indicates the completion of ten increments.

The pin 5 of IC2 was connected to the CLK pin of the IC1. Therefore whenever 10 counts was completed by the 7 segment at the right side, the high to low signal at the pin 5 will feed a single clock pulse input to the IC1 and therefore the corresponding 7 segment will be incremented one value. In the same manner IC2 will count from 0 to 9 and then value in the IC1 will be incremented by one. Thus this counter circuit is capable of counting upto 99 and then returns to zero.

NOTE:

  • Each push button switch differs in properties so as their debounce delay, so if you face problem in multiple increments of 7 segment values increase the values of Resistor R2 and Capacitor C2.
  • If you want your circuit to automatically count the values, then replace the Monostable Multivibrator with Astable Multivibrator with assigned time period.

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Ingyinn Khin
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Ingyinn Khin

I want to know what type of switch is used?In 7 segment digit,common pin is ground pin?

Ingyinn Khin
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Ingyinn Khin

And 7 segment can use both cathode and anode?

noo
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noo

hello guys i need some help how could i make a counter and display it by two digit seven segment display the project is that i have 12 inputs and its should display how many inputs are full .. what should i do … using simple gates can u answer me as fast as u can

Josue
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Josue

Hi Frank so I got it to count but its still not debouncing the signal so both digits are counting at the same time. What is it about the 555 timer that should help it debounce do that only the right side increments by one first?

Josue
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Josue

Hi in the circuit diagram above there is no pin 16 mentioned for the 4026 I was wondering if they need to be connected to the positive terminal?

Camille
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Camille

im working on this two digit counter with 555 ic, 4026 ic and we have this 100k potentiometer, it’s not counting right, the pulse is not working but whenever i click the reset button continuously the 1st 7 segment counts but the 2nd one isn’t counting. seems like the 1st one does the job of the 2nd 7 segment. that’s my problem. help pleaseee. i don’t know what’s wrong with my circuit but i followed the schematic diagram carefully.

Aijaz
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Aijaz

Sir can you made video of this circuit

ahmed khalaf
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ahmed khalaf

Kindly, 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?

ASHA
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ASHA

hello sir, am doing a project on transistor based application.instead of ic555 am using LDR and transistor.can i use any other counter ic instead of 4026.plz help me sir.

Phil Dee
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Phil Dee

Hi Frank,
I want to turn off/on the display. I discovered that grounding pin 3 and pressing the reset button before powering up the circuit disables the display. I can then jumper pin 3 to vcc to enable the display, but then hoe do I turn it back off, and then on, then off, etc?
I’m lost as how to do this in order to save battery power as I leave it on overnight. thanks.

Fisnik
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Fisnik

Can you provide me the truth table and k-diagrams because i need this for a school project
Thank you
Respect (:

Joe Wolf
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Joe Wolf

How do you automate the PTM button in the bottom left?