Help with SN74LS191

SN74LS191 (TI) - SYNCHRONOUS UP/DOWN COUNTERS WITH DOWN/UP MODE CONTROL, Counters

Please see the datasheet above of SN74LS191 and help me using this.
I'm making Digital switching system as a project where different IC (74ls93) was used and now not available in market.Now im using LS191 and finding difficulty in its input.
I need ur help...
I'm a student and new to this work.
Below is my project description
**broken link removed**

The 74ls93 is available and in stock at Digikey -
Digi-Key - 296-3750-5-ND (Texas Instruments - SN74LS93N)

You can also use a 74HC93 as a direct replacement. It works better and is easier to find. 74LS is old. 74HC is new.

duffy said:

You can also use a 74HC93 as a direct replacement. It works better and is easier to find. 74LS is old. 74HC is new.

Click to expand...

Be aware that, although the 74HC93 is functionally equivalent to the 74LS93, 74HC devices are CMOS and have somewhat different operating and I/O characteristics than the 74LS devices, which are bipolar.

I consider it remarkable that such a circuit is still being built from conventional digital logic.

As far as i understand, such design is now understood as inflexible,
because it is hardwired.

Maybe it is a good exercise for students.

my question is, if the OP has designed the circuit freshly, or if it was found in a book etc.?

also it is unknown if it is the OP's own website.

when i look the schematic, there is some device which has a BCD or 4bit hex output.
I'd suggest to install a mechanical hex/BCD encoder, and test the circuit.

anyway it's a limited design, as far as i understand only one load can be selected at one point of time.