My problem is related to these components. I'm trying to understand how I can set my own sequence of numbers with a 74ls90(decade counter) and 74ls47(BCD to seven segment decoder). I've manged to understand to understand to figure out how to reset a count if the numbers are consecutive(0.1.2.3..0..etc..), but I'm having trouble trying to set 0,3,4,7,0 or 0,2,4,6,0.

I'm been playing with it for sometime and tried the net but couldnt find anything specific. If somebody knows and if they could explain it to me, that would be great.

Thanks

Hi all,
I found a good schematic for a four decade counter using 4026 IC's with a switch debouncing circuit as well. It does not use the same IC's as in this discussion but you can add as many seven segment displays as you want.
The 4026 IC only drives common cathode seven segment displays and the nice part here is that only one IC per display necessary.
If you are interested the project is at :

http://braincambre500.freeservers.co...%20counter.htm

Barry.

Originally Posted by tresca

My problem is related to these components. I'm trying to understand how I can set my own sequence of numbers with a 74ls90(decade counter) and 74ls47(BCD to seven segment decoder). I've manged to understand to understand to figure out how to reset a count if the numbers are consecutive(0.1.2.3..0..etc..), but I'm having trouble trying to set 0,3,4,7,0 or 0,2,4,6,0.

I'm been playing with it for sometime and tried the net but couldnt find anything specific. If somebody knows and if they could explain it to me, that would be great.

Thanks

The only way I can see to do this is to configure the counter as a Modulo 4 and then design gating to give you 0, 3, 4, 7 rather than 0, 1, 2, 3. In other words, the counter is actually counting 0, 1, 2, 3, but the gating converts these to 0, 3, 4, 7 which then drives the binary to 7 segment IC.

To obtain 0, 2, 4, 6 you would use a diffiernt gating design.

Len

Greeting to all.

I built that circuit in electronics worbench and it acts like crazy.the problem is not the circuit , for some reason the 7 segment display that should turn ligths on at high input ( as explained in help option :roll: )is inverted so it ligths in low level.

Just wanted to add a note here in case anybody else come across the need in playing around with 74LS90 circuits:

http://travel.howstuffworks.com/digital-clock5.htm

Gives examples of setting up divide-by-10 counters and divide-by-6 counters to create a digital clock.

Okay i'm kind of new at this and I'm using multisim7. For my project I need some sort of timing device. After 5 sec, I need ouputs to change. Then after 23 sec, I need outputs to change again. Then after 25 seconds I need those outputs to change once more. I imagine I'll use a counter, but I'm really not sure how I go about making a truth table or hooking up multiple counters. I think counters like the 74192 or 7490 or 74161 could be used?? Can anyone help me out??? I'm kind of....clueless and I'd appreciate any help. Oh and I can only usre 74xxx series ICs.

Thanks.

Hi,
I also build this counter and its works well, but I have one problem that when I switch on the power of counter its displays 8 rather than 0. Please help me in this metter if you know anything about it.
Project diagram is received by http://www.aaroncake.net/circuits/counter.htm

The circuit needs 2 additions.

1. Switch on reset so it starts at 0

2. a 100 nF bypass capacitor across the counter supply pins. Strange results can occur otherwise

Len

74ls47 have open collector outputs, chances are your simulation software includes this in its models as well. This means you should tie them high using 1K pull up resistors and then use inverters between the 7447 output to your 7 seg display. Try it.

Hey, I am building this counter right now and i can't get it running. Is there a switch required? And what do you with Pin 14 where it says "count in". Please if anyone can help me it would be great!

BTW: there is not a youtube vid on building this, is there? Maybe someone could make one since everyone has trouble with this circuit

Thanks in advance!

for me works fine i just needed to add NOT gate at the end

see picture
ImageShack - Image Hosting :: 26740674jn6.jpg

neeeeeeeeed digital clock complete circuit diagram

can i have a schematic diagram of 74LS192 and 74LS47 with up/down counter???