Hey everyone!

As part of a project, I have to create a 4-bit counter and a BCD to 7-segment decoder, that takes the value produced by the counter and displays it on a LED. I have completed the circuit in Multisim, but the only value displayed on the LED is "1". I've been trying -unsuccesfully- for hours to solve the problem, but at this point I am pretty stack. I've attached the circuit for anyone who'd care to have a look and offer some assistance.

 

Have you checked the 4 bit counter? It sounds like it counts only one time, from 0 to 1, and then stops, so you only get 1 on the 7 segment display.

 

I think it should work the way I've designed it and reset after going to 9. But it really doesn't seem to be functioning that way for some reason.

 

Try taking a screenshot of your schematic, otherwise, the only way to view your circuit it's with Multisim...

 

Here is the screenshot:

http://i58.tinypic.com/2s1ov3a.jpg

 

Try remove R4 470Ω and see if it works.

I think the resistance is too low for the AND gate to pull its output high..

Allen

 

Just tried removing the R4. Unfortunately, I only get "1" displayed still

 

Problem solved. Being really bad with physics, I had messed up the resistance and capacitor values of the 555. Here is a screenshot of it working properly for anyone interested.

http://i60.tinypic.com/2rzqgb7.jpg