LESSON 2
DESCRIBE LOGIC SYSTEMS
TASK
Describe and identify how logic gates are combined and the changes of their outputs.
CONDITIONS
Given information about logic gates, describe the differences of some systems and their outputs.
STANDARDS
Demonstrate competency of the task skills and knowledge by completing a series of truth tables and by
correctly responding to 80 percent of the multiple-choice test questions relating to logic systems.
REFERENCES
None
Learning Event 1:
DEFINE A LOGIC SYSTEM
1.
The term "system" is used two different ways in binary logic. Logic system is used to mean an
entire piece of equipment and groups of equipment that work together. It is also used to mean
combinations of the basic symbols into groups that each perform a complete function.
2.
When the term logic system is used in connection with equipment, it refers to the voltages that
are used as signal levels and indicates which voltage represents a binary 1. A negative logic system uses
negative logic, and a positive logic system uses positive logic.
3.
Systems as discussed in this portion are simple combinations of the basic symbols into groups.
By this definition, a group of gates that performs addition is a system; a group of gates that monitors
several signals and initiates an alarm if any signal fails is also a system.
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