hello,
I want to display countdown on seven segment but I don't know the method to do it... Please help me...

 

Well, give us a hint as to what you are attempting to do.
What seven segment displays are you planning on using? LED? LCD?
Common anode? Common cathode? Current, voltage rating?
Power supply voltage and current rating?
How many digits?
Frequency of count down rate?
What number are you starting and ending in the count down?
What are counting down?

 

common cathode
does it work on 5V?
count down - 9-0
frequency rate - 1digit per sec
only one digit can be displayed at one time on seven segment display

 

How about this:

http://www.ebay.com/itm/5-Digital-L...t=LH_DefaultDomain_0&var=&hash=item233c054d33

 

Is this an assignment from a teacher/instructor/professor as homework?

Small LED 7-segment displays generally will operate from 5v or even less, but large LED displays may have multiple LEDs in series internally, thus need higher voltages before they will illuminate.

Common-cathode displays require that you source current to the a thru g segment input pins to output light.

Are you planning on using 74-series TTL components, 4000-series CMOS, or perhaps a microcontroller?

 

how

How about this:

http://www.ebay.com/itm/5-Digital-L...t=LH_DefaultDomain_0&var=&hash=item233c054d33[/QUOTE how to make it?

 

Is this an assignment from a teacher/instructor/professor as homework?

Small LED 7-segment displays generally will operate from 5v or even less, but large LED displays may have multiple LEDs in series internally, thus need higher voltages before they will illuminate.

Common-cathode displays require that you source current to the a thru g segment input pins to output light.

Are you planning on using 74-series TTL components, 4000-series CMOS, or perhaps a microcontroller?

through microcontroller

 

I really don't care to play game of 100 and 1 Questions.

Here is 7 seg display in 3 easy steps, copy that: http://makezine.com/projects/drive-a-7-segment-led-with-an-arduino/

 

I really don't care to play game of 100 and 1 Questions.

Here is 7 seg display in 3 easy steps, copy that: http://makezine.com/projects/drive-a-7-segment-led-with-an-arduino/

I know very well how to drive seven segment, which I want to know that is how to show countdown like traffic light system?

 

Read:http://www.elektroniksforkids.com/p...-Seven-Segment-LED,-IC-4026-and-Timer-555.php

 

I know very well how to drive seven segment, which I want to know that is how to show countdown like traffic light system?

I would take a uC like Arduino board and write a program to do the count. It is a bit of overkill, but from where I sit, it is the easiest to do.

 

If you want a microcontroller solution here is a simple example:

http://forum.allaboutcircuits.com/blog/msp430-seven-segment-led-driver.557/

 

thanks everyone..