Lesson 2.3 Key Terms
Specific Combinational Logic Designs
Term
Definition
Common Anode
Display
A seven-segment LED display where the anodes of all the LEDs
are connected to the circuit supply voltage. Each segment is
illuminated by a logic LOW at its cathode.
Common Cathode
Display
A seven-segment display in which the cathodes of all the LEDs are
connected together and grounded. A logic HIGH illuminates a
segment when applied to its anode.
Datasheet
A printed specification giving details of the pin configuration,
electrical properties, and mechanical profile of an electronic device.
De-multiplexer
A circuit that uses a binary decoder to direct a digital signal from a
single source to one of several destinations.
Design Specifications A detailed description, especially one providing information needed
to make, build, or produce something.
Encoder
A digital circuit that produces an output code depending on which of
its inputs is activated.
Exclusive-NOR (XNOR) Two-input logic circuit that produces a high output only when the
Circuit
inputs are equal.
Exclusive-OR (XOR)
Circuit
Two-input logic circuit that produces a high output only when the
inputs are different.
Full Adder
Logic circuit with three inputs and two outputs. The inputs are a
carry bit (CIN) from a previous stage, a bit from the augend, and a
bit from the addend, respectively. The outputs are the sum bit and
the carry-out bit (COUT) produced by the addition of the bit from the
addend with the bit from the augend and CIN.
Half Adder
Logic circuit with two inputs and two outputs. The inputs are a bit
from the augend and a bit from the addend. The outputs are the
sum bit produced by the addition of the bit from the addend with the
bit from the augend and the resulting carry (COUT) bit, which will be
added to the next stage.
Hexadecimal Number Base-16 number system. Hexadecimal numbers are written with
System
sixteen digits, 0-9 and A-F, with power-of-16 positional multipliers.
Multiplexer
A circuit that directs one of several digital signals to a single output,
depending on the states of several select inputs.
Octal Number System A number system that has a base of 8; digits from 0 to 7 are used
to express an octal number.
© 2014 Project Lead The Way, Inc.
Digital Electronics Lesson 2.3 Specific Combinational Logic Designs Key Terms – Page 1
Seven-Segment
Display
An array of seven independently controlled light-emitting diodes
(LED) or liquid crystal display (LCD) elements, shaped like a figure8, which can be used to display decimal digits and other characters
by turning on the appropriate elements.
Signed Binary Number A binary number of fixed length whose sign is represented by one
bit, usually the most significant bit, and whose magnitude is
represented by the remaining bits.
Sign Bit
A binary bit that is added to the leftmost position of a binary number
to indicate whether that number represents a positive or a negative
quantity.
1’s Complement
A form of signed binary notation in which negative numbers are
created by complementing all bits of a number, including the sign
bit.
2’s Complement
A form of signed binary notation in which negative numbers are
created by adding 1 to the 1’s complement form of the number.
© 2014 Project Lead The Way, Inc.
Digital Electronics Lesson 2.3 Specific Combinational Logic Designs Key Terms – Page 2