Help identifying a counter IC (Electronics)

Danny091

Danny091

Danny091

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Hi all i am wondering if anyone that has experience in electronics could identify what counter type this is.

Its meant to be talking the clock pulse from an a-stable and resetting after 5 or up to 5 I'm not quite sure!

http://i.imgur.com/LVFTgwB.jpg

C , B , A go into logic gates that light up LED's
 
The pins go upto atleast 38? thats a fair sized chip.

I'd guess it would be something in the 4xxx range of ICs off the top of my head.

You can use a decade counter (4017) for that kind of use but not sure what this circuit is supposed to be using - do you have any more information?

EDIT: Closest I can find off the top of my head is the 7490 - it has clck on 14, vcc on pin 5 and gnd on 10 which that seems to show. (that diagram linked is missing any reset functionality though). 7400 series seem to match the pinout but I can't put my finger on the correct one.
 
Last edited:
Rroff said:
The pins go upto atleast 38? thats a fair sized chip.

I'd guess it would be something in the 4xxx range of ICs off the top of my head.

You can use a decade counter (4017) for that kind of use but not sure what this circuit is supposed to be using - do you have any more information?

EDIT: Closest I can find off the top of my head is the 7490 - it has clck on 14, vcc on pin 5 and gnd on 10 which that seems to show. (that diagram linked is missing any reset functionality though). 7400 series seem to match the pinout but I can't put my finger on the correct one.
Click to expand...

Hi no i think its connecting the pins together so pin 3 and 8 together ext. Its actually for an electronic dice i built as my GCSE project about 7 years ago. Id like to build it again to have on my desk kind of thing

http://imgur.com/a/s0GL0

This is all i could find in my school book about it. Essentially the astable makes the counter count so quick that its impossible to tell what number you will stop on.
The nand gates go to the LEDs which are arranged like this (numbers correspond)

O (1) O(4)
O(2) O(7) O(5)
O(3) O(6)
 
Ah 1 and 2 and 2 and 9 separately tied together threw me, looks like it probably is a 7490 but still a couple of things that don't quite make sense.
 
Yeh and it was so long ago i cant remember :( I do know i managed to actually get it working though! What doesnt make sense to you?
 
I think i have figured it out now thanks! your right i believe it is a 7490.

I believe pins 3 and 8 are together and pins 2 and 9 while it shows pins 1 and 2 together is wrong its just pin 12. (not 1 and 2)

The 7490 resets to 0 when pin 2 and 3 are high (1)
this will happen when it gets to 6 because pins 8 and 9 will both be a 1
pin 8 is QC and pin 9 is QB

QD QC QB QA
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
0 1 0 1
0 1 1 0

i think? lol
 
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