Access Time: Time between the memory receiving a new input address and the output data s becoming available in a read operation.

Active Load: A transistor that acts as a load for another transistor.

Active Low: The low state is the one that causes the circuit to become active rather than the high state.

Active Power Dissipation: The power dissipation of a device under switching conditions. It differs from static power dissipation because of the large current spikes during output transitions.

ADC: Analog-to-digital converter.

Addend: Number to be added to another.

Alphanumeric Codes: Codes that present numbers, letters, punctuation marks, and special characters.

Arithmetic-Logic Unit (ALU): Digital circuit used in computers to perform various arithmetic and logic operations.

Assert: To activate. If an input line has a bubble on it, the input can be asserted by making it low.

Astable Multivibrator: Digital circuit that oscillates between two unstable output states.

Asynchronous Transfer: Data transfer performed without the aid of a clock.

Augend: Number to which the addend is added.

Bilateral Switch: CMOS switch which acts like a single-pole, single-through switch (SPST) controlled by an input logic level.

Binary Numbers: A number code that uses only the digits 0 and 1 to represent quantities.

Bipolar: Having two types of charge carriers; free electrons and holes.

Bistable Multivibrator: Name that is sometimes used to describe a flip-flop.

Bit: An abbreviation for binary digit. It combines the first letter of binary and the last two letters of digit.

Buffer/Driver: Circuit designed to have a greater output current and/or voltage capability than an ordinary circuit.

Buffer Register: Register that holds digital data temporarily.

Byte: A binary number with 8 bits.

Checksum: Special data word stored in the last ROM location. It is derived from the addition of all other data words in the ROM, and is used for error checking purposes.

Compatibility: Ability of the output of one device to drive the input of another device.

Contact Bounce: Opening and closing of a set of contacts as a result of the mechanical bounce that occurs when the device is switched.

DAC: Digital-to-analog converter.

Data Selector: A synonym for multiplexer.

Decoder: A circuit that is similar to demultiplexer, except there is no data input. The control input bits produce one active output line.

Demultiplexer: A circuit with one input and many outputs.

Differential Linearity: A measure of the variation in size of the input voltage to an A/D converter which causes the converter to change from one state to the next.

DIP: Dual-in-line package. This is the most common type of IC package.

Don't-Care Condition: An input-output condition that never occurs during normal operation. Since the condition never occurs, one can use an X on the Karnaugh map. This X can be a 0 or 1, whichever is preferable.

Edge Detector: Circuit that produces a narrow positive spike that occurs coincident with the active transition of a clock input pulse.

Encoder: Digital circuit that produces an output code depending on which of the inputs is activated.

EPROM: An erasable programmable read-only memory. With this device, the user can erase the stored content with ultraviolet light and electrically store new data.

Even Parity: A binary number with an even number of 1s.

Fall Time: The time required for a signal to transition from 90 percent of its maximum value down to 10 percent of its maximum.

Fan out: Maximum number of standard logic inputs that the output of a digital circuit can drive reliably.

Full-Adder: A logic circuit with three inputs and two outputs. The circuit adds 3 bits at a time, giving a sum and carry output.

Glitch: Very narrow positive or negative pulse that appears as an unwanted signal.

Half-Adder: A logic circuit with two inputs and two outputs. The circuit adds 2 bits at a time, giving a sum and carry output.

Hold Time: The minimum amount of time that data must be present after the clock trigger arrives.

Inhibit Circuits: Logic circuits that control the passage of an input signal through to the output.

Karnaugh Map: A drawing that shows all the fundamental products and the corresponding output values of a truth table.

LED: A light-emitting diode.

Logic Circuit: A digital circuit, a switching circuit, or any kind of two-state circuit that duplicates mental processes and behaves according to a set of logic rules.

Low-Power Schottky TTL (LS-TTL): TTL subfamily that uses the identical Schottky TTL circuit but with larger resistor values.

Low-Power TTL: TTL subfamily that uses basic TTL standard circuit except that all resistor values are increased.

LSB: Least significant bit.

Millman's Theorem: A theorem from network analysis which states that the voltage at any node in a resistive network is equal to the sum of the currents entering the node divide by the sum of the conductances connected to the node, all determined by assuming the voltage at the node is zero.

Modulus: Defines the number of states through which a counter can progress.

MSB: Most significant bit.

Multiplexer: A circuit with many inputs and one output.

Natural Count: The maximum number of states through which a counter can progress. It is given by 2n, where n is the number of flip-flops in the counter.

Nibble: A binary number with 4 bits.

Octet: Eight adjacent 1s in a 2×4 shape on a Karnaugh map.

Odd Parity: A binary number with odd number of 1s.

Offset Error: Deviation from the ideal zero volts at the output of a digital-to-analog converter when the input is all 0s. In reality, there is a very small output voltage for this situation.

Overflow: An unwanted carry that produces an answer outside the valid range of the numbers being represented.

Overlapping Groups: Using the same 1 more than once when looping the 1s of a Karnaugh map.

Pair: Two horizontally or vertically adjacent 1s on a Karnaugh map.

Percentage Resolution: Ratio of the step size to the full-scale value of a digital-to-analog converter. Percentage resolution can also be defined as the reciprocal of the maximum number of steps of a digital-to-analog converter.

Priority Encoder: Special type of encoder that senses when two or more inputs are activated simultaneously and then generates a code corresponding to the highest-numbered input.

Product-of-Sums Equation: A Boolean equation that is the logical product of logical sums. This type of equation applies to an OR-AND circuit.

Quad: Four horizontal, vertical, or rectangular 1s on a Karnaugh map.

Quantization Error: The error inherent in any digital system due to the size of the LSB.

Redundant Group: A group of 1s on a Karnaugh map that are all part of other groups. Redundant groups may be eliminated.

Rise Time: The time required for a signal to transition from 10 percent of its maximum value up to 90 percent of its maximum.

SAR: Sequential approximation register, used in a sequential ADC.

Setup Time: The minimum amount of time required for data inputs to be present before the clock arrives.

Static Power Dissipation: The product of DC voltage and current.

Strobe: An input that disables or enables a circuit.

Sum-of-Products Equation: A Boolean equation that is the logical sum of logical products. This type of equation applies to an AND-OR circuit.

Timing Diagram: A picture that shows the input-output waveforms of a logical circuit.

Truth Table: Logic table that depicts a circuit's output response to the various combinations of the logic levels at its inputs.

Wired-AND: Term used to describe the logic function created when open-collector outputs are tied together.