Hi all,
i am having a problem with the 74ls193 when i am testing it on breadboard.I have it preset at 9 and count down. But when it is counting down the number is jumping around. Can anyone pls help me. And that is my schematic diagram. But when in multisim it work perfectly ok.

 

You do not show a 0.1uF bypass capacitor across the Vcc and GND leads. This is a minimum requirement for any IC. Many IC's require more than that, such as a 555 timer - they need an 0.1uF and a 1uF minimum.

You are suffering from "switch bounce".

Look here: http://www.ganssle.com/debouncing.htm
It will save me lots of typing, and explain ways to de-bounce your switches.