7 Segment LED Counter

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This simple counter can be used to count pulses, as the basis for a customer counter (like you see at the doors of some stores), or for anything else that may be counted. The circuit accepts any TTL compatible logic signal, and can be expanded easily (see Notes).

Schematic

7 Segment Display Reference

Parts

Part	Total Qty.	Description	Substitutions
R1-R7	7	470 Ohm 1/4 Watt Resistor
U1	1	74LS90 TTL BCD Counter IC	7490,74HC90
U2	1	74LS47 TTL Seven Segment Display Driver IC	7447,74HC47
DISP1	1	Common Anode 7 Segment LED Display
MISC	1	Board, Sockets For ICs, Wire

Notes

All pulses to be counted are to be TTL compatible. They should not exeed 5V and not fall below ground.

You can add more digits by building a second (or third, or fourth, etc...) circuit and connecting the pin 11-6 junction of the 74LS90 and 74LS47 to pin 14 of the 74LS90 in the other circuit. You can keep expanding this way to as many digits as you want.

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Comments

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anonymous Help! Added 555 timer for this counter. Wednesday, September 23, 2009 1:34:16 AM

I built this circuit using 555 timer Astable as my pulse. My problem is that it skips numbers. Like it will count from 1 to 4 then 7 and back to 1. Some times its random numbers. I thought I might have had some bad chips but I replaced them with new ones. For the 555 timer I am using R1 10k R2 100k and 10uF for a frequency of .068Hz. Doesn't any body have any suggestion why this might be skipping numbers?

Danpher 7 Segment LED Counter Monday, September 14, 2009 10:58:42 PM

i am about to design a 24-second shot clock using the seven-segment light emitting diode....if you have an idea on this matter, kindly send to me steps to be followed in makikng such device....

nina 7 Segment LED Counter Sunday, September 13, 2009 3:03:47 PM

hi! i was just wondering, i am looking for a circuit that counts up to 12...can i get any help with that?..esp on how to expand this particular circuit to be able to do that. thanks!

chillychintu 7 Segment LED display Sunday, September 13, 2009 3:35:59 AM

hey anyone know's how to display alphabets in common cathode seven segment display? If yes then give me a brief description about it on my mail.. I will be really grateful

Ronald Cayne 7 Segment LED Counter & Mercury Switch Saturday, September 12, 2009 2:40:56 PM

Hi There I am a real novice but want the following. Help would be greatly appreciated. Can I use 12 V DC Circuit with this device? What alterations would be required. I am using a mercury switch and everytime the circuit closes even momentarily I want to record the count, Source is a 12VDC coming from my auto battery. Please help as to where the various components can be purchased. Thanks Ron Cayne

trevor double 7 Segment LED Counter Thursday, August 27, 2009 5:48:35 AM

i want to build counter circuit that counts to 108..using a toggle button it must increment by 1 everytime the button is pressed when entering and decrement by 1 everytime the button is pressed when exiting

rowan 7 Segment LED Counter Friday, August 21, 2009 6:51:10 AM

michael, you must use a synchrous up/down bcd counter ic.. you can use a 74ls190.. you can check this link.. http://rowatronix.wordpress.com/2009/05/09/updown-counter-circuit/

Michael 7 Segment LED Counter Tuesday, July 07, 2009 11:27:59 PM

Would like to make a count up to 20 and down to 0 seven segment display using two manual momentary switches. any help would be appreciated.

fahim 7 Segment LED Counter Tuesday, May 26, 2009 8:20:08 AM

i want conected 7447 with seven segment. how do i that?

ginvin 7 Segment LED Counter Wednesday, April 29, 2009 12:00:47 PM

I have a 12V DC fan motor, it have 3 wires, one of it, output the pulse width signal. Now I want to convert the pulse signal to speed (r.p.m) to show on 7 segment. How can I do it??? Thank you very much!

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anonymous	Help! Added 555 timer for this counter.	Wednesday, September 23, 2009 1:34:16 AM
I built this circuit using 555 timer Astable as my pulse. My problem is that it skips numbers. Like it will count from 1 to 4 then 7 and back to 1. Some times its random numbers. I thought I might have had some bad chips but I replaced them with new ones. For the 555 timer I am using R1 10k R2 100k and 10uF for a frequency of .068Hz. Doesn't any body have any suggestion why this might be skipping numbers?
Danpher	7 Segment LED Counter	Monday, September 14, 2009 10:58:42 PM
i am about to design a 24-second shot clock using the seven-segment light emitting diode....if you have an idea on this matter, kindly send to me steps to be followed in makikng such device....
nina	7 Segment LED Counter	Sunday, September 13, 2009 3:03:47 PM
hi! i was just wondering, i am looking for a circuit that counts up to 12...can i get any help with that?..esp on how to expand this particular circuit to be able to do that. thanks!
chillychintu	7 Segment LED display	Sunday, September 13, 2009 3:35:59 AM
hey anyone know's how to display alphabets in common cathode seven segment display? If yes then give me a brief description about it on my mail.. I will be really grateful
Ronald Cayne	7 Segment LED Counter & Mercury Switch	Saturday, September 12, 2009 2:40:56 PM
Hi There I am a real novice but want the following. Help would be greatly appreciated. Can I use 12 V DC Circuit with this device? What alterations would be required. I am using a mercury switch and everytime the circuit closes even momentarily I want to record the count, Source is a 12VDC coming from my auto battery. Please help as to where the various components can be purchased. Thanks Ron Cayne
trevor	double 7 Segment LED Counter	Thursday, August 27, 2009 5:48:35 AM
i want to build counter circuit that counts to 108..using a toggle button it must increment by 1 everytime the button is pressed when entering and decrement by 1 everytime the button is pressed when exiting
rowan	7 Segment LED Counter	Friday, August 21, 2009 6:51:10 AM
michael, you must use a synchrous up/down bcd counter ic.. you can use a 74ls190.. you can check this link.. http://rowatronix.wordpress.com/2009/05/09/updown-counter-circuit/
Michael	7 Segment LED Counter	Tuesday, July 07, 2009 11:27:59 PM
Would like to make a count up to 20 and down to 0 seven segment display using two manual momentary switches. any help would be appreciated.
fahim	7 Segment LED Counter	Tuesday, May 26, 2009 8:20:08 AM
i want conected 7447 with seven segment. how do i that?
ginvin	7 Segment LED Counter	Wednesday, April 29, 2009 12:00:47 PM
I have a 12V DC fan motor, it have 3 wires, one of it, output the pulse width signal. Now I want to convert the pulse signal to speed (r.p.m) to show on 7 segment. How can I do it??? Thank you very much!