4) Design a one-input, one-output serial 2's complementer. The circuit accepts a string of bits from the input and generates the 2's complement at the output 5) Design a sequential circuit with two JK flip-flops A and B and two inputs E and F. If E-0, the circuit remains in the same state regardless of the value of F. When E - 1 and F-1, the circuit goes through the state transitions from 00 to 01, to 10 to 11, back to 00, and repeats. When E= 1 and F = 0, the circuit goes through the state transitions from 00 to 11, to 10, to 01, back to 00, and repeats