1. The problem statement, all variables and given/known data Make a BCD 3321 encoder. So if you input 0100, the encoder will output (depending on your design) either a 1001, or a 0101. Similarly, an input of 0101 will output either a 1010 or a 0110 (again, depending on your design). 2. Relevant equations I know you're supposed to use DeMorgan's Law, but I have a hard time understanding WHEN to use it. 3. The attempt at a solution I have done the truth table, the kmaps, and derived the logical expressions for each bit, but what I'm having a hard time doing is turning my AND-OR logic expressions into NAND-NAND logic expressions. My 4 logical expressions are: (3) MSB: A + BC (3) Second MSB: A + B + CD (2) Third MSB: A + BC'D + B'CD' (1) LSB: BCD + BC'D' + B'C'D My professor mentioned something about double negating the equations, and then applying DeMorgan's Law to get the NAND-NAND logic, and that's where he lost me. Any help will be greatly appreciated!