Combinational Logic and The Wonders of 581AH

EE481 Logic Design Lab
Fall 2003, Lab #1

Prelab Questions

  1. Show a design for a circuit tex2html_wrap_inline52 implemented with AND gates and inverters.
  2. What is the minimal Sum of Products (SOP) form? How does it differ from the Canonical Sum of Products form?
  3. Show the minimal SOP, minimal POS, Canonical POS, and Canonical SOP for: tex2html_wrap_inline54
  4. Answer the following questions using your TTL book:
  • What would the drop resistor for an LED need to be if: We wanted to connect the LED to of +5v; The forward biased LED junction drops .9v; Max current through the LED is 20mA.
  • Design a circuit with 8 bits as input that will display on a 7-segment display:
  • Design a combinational circuit that uses only NAND gates to implement a security system for a vault. The circuit has two inputs ``A'' (that is high when the system is armed, low else) and ``D'' (that is high when the door i s open, low else) and two outputs ``G'' (green LED) and ``R'' (red LED). The circuit will operate as follows: