2's complement with JK and Multiplexer

[Claudiu]

Hi all ,
I try to create a circuit who can show the 2's complement for 8 bit numbers.I have to use JK Flip Flop and Multiplexer but i am not understand how these are connecting.I have IC CD4027 but i don't know how to use it in combination with Mux and how many JK are necessary.
Can someone give me an electrical schema or any advice?
Thanks.

 

[Harald Kapp]

You do know how a 2's complement number is mathematically created from the input, do you?

This is a mathematical operation involving subtraction or inverting and addition. In no way is a flip flop directly involved (other than maybe storing the input and/or output and thus serving as a latch only).
It is possible to abuse the CD4027 as an inverter by using the set and reset inputs only (see datasheet, page 5).

You're still missing the required adder function. That's where the multiplexer comes into play. You can construct an adder from a multiplexer.

You now have inverters and adders, everything you need to make a 2's complement circuit.

 

[Claudiu]

Hi,
I tried to make an circuit.
I guess that now i have an inverter(CD4027) but i don't know how to create that adder with 74LS151N.
Thanks.

 

[Harald Kapp]

Please upload a regular schematic diagram. Following a nest of wires on a breadboard is rather difficult (although you setup does look reasonably neat ).

i don't know how to create that adder with 74LS151N.

Follow the last link in my post #2.