Static 0 to 9 display
Description.
The circuit shown here is of a simple 0 to 9 display that can be employed in a lot of applications. The circuit is based on asynchronous decade counter 7490(IC2), a 7 segment display (D1), and a seven segment decoder/driver IC 7446 (IC1).
The seven segment display consists of 7 LEDs labelled ‘a’ through ‘g’. By forward biasing different LEDs, we can display the digits 0 through 9. Seven segment displays are of two types, common cathode and common anode. In common anode type anodes of all the seven LEDs are tied together, while in common cathode type all cathodes are tied together. The seven segment display used here is a common anode type .Resistor R1 to R7 are current limiting resistors. IC 7446 is a decoder/driver IC used to drive the seven segment display.
Working of this circuit is very simple. For every clock pulse the BCD output of the IC2 (7490) will advance by one bit. The IC1 (7446) will decode this BCD output to corresponding the seven segment form and will drive the display to indicate the corresponding digit.
Circuit diagram.
Notes.
- The circuit can be assembled on a perf board.
- Use 5V DC for powering the circuit.
- The clock can be given to the pin 14 of IC2.
- D1 must be a seven segment common anode display.
- All ICs must be mounted on holders.
Sir,
U can’t evev imagine tht hw mch th abov ckt help in doing my mini project.thnk u so mch
Hi,
Sir why we use R1 to R7 = 220ohm resistors in this ckt………? Can we use the other resistors which have different values. e.g (R1 to R7 = 1kohm, 50ohm etc;) except R1 to R7 = 220ohm.
Urgently plzzzzzzzz or mail me on my id (ijazktk1@yahoo.com)
Thanks & Regards.
Ijaz KTK
Well, you can use. But remember as you keep increasing the resistor value the brightness of the display keeps decreasing. And yes, decreasing the resistor value below 220R will increase the brightness but will also damage the display. Hope you get this. BTW, read some good basic electronics.
Had to switch out 7446 to a 7447 to get the decade counter to work
how i can display 0 to 9 random?it means that like flasher not counter
hi sir, my question is same as louie.
fyi, i had put a switch to make the display stay at 9 and it’s succesful but what other components that i can use to replaced the switch? can we use gates? and if yes, how should i place it? i want it to stop and stay at 9 automatically. please help me. i wanna know this really bad. thank you sir. have a nice day
I want u’r ckt
Sir !
This o to 9 counter is well but wht should we do if we need to implement a more than one digit counter ?
Hi Priyank input pulse is given to Pin14 of the IC to count. each pulse it will move to next number in ascending order. You can use apush to on switch connect between 5volt and Pin14. for each push the number will advance.
sir,
it is necessary to give clockpuls to corcuit ya we give inplace of clockpuls a 5v of batttery???
sir how can i do a counter just like this except that it will not reset after reaaching 9 but will stay at 9. for example 1 2 3 4 5 6 7 8 9, after 9 it wont loop to zero and just stay there. thanks
Sir a have a few questions to ask and i need you to answer my questions immediately please coz tomorrow i’ll be defending my project and one of the circuits that i used there is your design,here are my questions:
1.Why is it that you didn’t use a encoder?usually there is an encoder before the decoder.
2.How did you compute the values of the resistor?
3.What is the use of the asynchoronous decade counter?Does it really need to be asynchronous?
4.What should be the clock that i will use here?can i use a 555 astable multivibrator circuit to provide the BCD input??
PLEASE REPLY..THANK YOU VERY MUCH SIR and to anyone who can help me..THANKS!
Sir,i wanted to know that can we use a astable circuit of 555 timer to feed the clock signal to Ic 7490??plz reply…
hello sir
can u help provide some circiuits that would displayed 0-9
with just a push botton.say e.g. ill presh #4 button and the led will automatically display (4)or else the #3 button and it also displayed (3) i really need it asap.plsssssss
thanks ………..
hi guys., pls help me,.i want to build an up and down counter using 1 digit seven segment display,.can somebody sends me a circuit that counts from 0-9 then will reverse. and the switch to be used is a sensor,.
Hi mr, seetharaman,
As you said, when i take carry from pin 11 i.e,QD then there is a count for numbers 8 (1000) and 9(1001) and i want a carry when the counter counts (0000)to initiate next counter.
Thanks a lot! . . . this ckt surely help me build a coin operated timer for a Inet CAFE.
see it here: http://www.jqsupport.blogspot.com
email me if u wanna share ideas with me…tnx
Hi Anish
1. Output QA is connected to input B for BCD count.
2. Output QD is connected to input A for binary count
Hi sir,
Thankyou for your kind reponse…
So, if i want to construct a bcd clock..
How to reset it after 6 counts?
I mean i have 6 7490ic and wanna build a bcd clock..
Hi Anish take carry signal from pin-11 of first divider to pin 14 (input) of next counter’ to achieve 0 to 99 count.
use this reference drawing
http://books.google.co.in/books?id=8CsTzbDU6cAC&pg=PA46&lpg=PA46&dq=how+to+divide+by+99+using+7490&source=bl&ots=yTMJqu67c6&sig=VAtu6H6YGRxTecK-FhCz2Y9m20g&hl=en&ei=0iP-Tfb1B47WvQOJ4pSOAw&sa=X&oi=book_result&ct=result&resnum=4&sqi=2&ved=0CC8Q6AEwAw#v=onepage&q&f=false
Hi sir,
How can we generate carry in the 7490 after the count of ten to start the counting of another display? for example, to build a counter to count from 0 t0 60 used for building binary clock?
Hi Amiri use CD4029 instead of CD4017. CD4029 is an up / down counter.
refer the application data
http://www.datasheetcatalog.org/datasheets/166/108968_DS.pdf
Hi sir,
Please send me the simple circuit of reverse countdown starting from 9 to 0…
I will be very thankful to u
Hi you guys. What I’m wondering is how to get the 7490 to reset to 1 instead of 0. I got two 7-segment displays that reset to zero after they reach 12. Another group is trying to get their two 7-segment displays to reset after 60.
thank you very much sir…
i’ll try it and send you the comment….
Hi Vasanth each positive going pulse to the input pin 14 will add 1 to indicated number. say if it was at 4 with one positive going input pulse it will change to 5 it will count up to 9 and reset back to zero.
you can simply produce pulse through a 10k resistance connected bet ween positive and pin 14 of the IC through bell push switch. each push will add one to the displayed digit.
sir,
how can i give clock pulse to this circuit?
if there any another circuit for that clock pulse, please provide me the details….