i read the datasheet of the 74LS47 but cant really understand how it works..
i just know that it is a BCD to 7 Segment decoder..
anyone can tell me more about 74LS47 function?
Ty.

 

i read the datasheet of the 74LS47 but cant really understand how it works..
Ty.

Which part of the function do you not understand?

 

how does it works basically? A very general one.
like why is it active-low at the outputs?

 

how does it works basically? A very general one.
like why is it active-low at the outputs?

7447 is is a simple IC that "converts" BCD code to LED 7-SEGMENT display.
And 7447 is design to driving command anode LED displays. And that is why we have active-low at the outputs.
http://en.wikipedia.org/wiki/Binary-coded_decimal
http://en.wikipedia.org/wiki/Seven-segment_display
And see the TRUTH TABLE
http://maven.smith.edu/~thiebaut/270/datasheets/sn74ls47rev5.pdf

 

Each segemnt of the display has associated with it a Boolean equation that determines weather the segment is on or off. For a single digit there will be seven equations, with each equation using four inputs. The equations can be written as a Sum of Products (SOP) or as a Product of Sums (POS) depending on which is easier to implement.

Here is the important point. A decoder is a combinatorial circuit with NO memory elements.

 

If you look at the datasheet provided here..... http://pdf1.alldatasheet.com/datasheet-pdf/view/51080/FAIRCHILD/74LS47.html

you can see the internal logic diagram. Hope this helps.

 

Hi! What's the difference between 74ls47 and 7447 ic??

thank you!
good evening!
marC

 

Have you looked at the spec sheets of each? No better way to learn!

 

No doubt that this is a resurrection!

Post a new thread if you need a question answered, not highjack a two year old one

 

Hi! What's the difference between 74ls47 and 7447 ic??

thank you!
good evening!
marC

The LS device has less drive capability and the inputs represent a smaller load. It's all in the datasheet. Get them, read them, and appreciate them!