Question

Design a decade counter using the following 2-4-2-1 weighted code for decimal digits. Use NAND gates and T flip-flops.

                                                            

Answer 1

Solution:

The Excitation Table of 2-4-2-1 counter is:

It can be illustrated through T Flipflops & the excitation table of T Flipflop is:

Excitation Table of a T Flip-Flop Interpretation of the transition Input required in the rth interval Transition (Tn) 0→0 01 Stores Toggles Toggles Stores

The K-Maps for input T_A,T_B,T_C,T_D & corresponding expressions obtained from K-Maps are:

From these map we obtain expressions:

& Here is the Modulo-10 counter: