National Instruments NI 4050 H, I

Glossary

harmonics multiples of the fundamental frequency of a signal

half-power bandwidth the frequency range over which a circuit maintains a level of at least –3dB

with respect to the maximum level

hardware the physical components of a computer system, such as the circuit boards,

plug-in boards, chassis, enclosures, peripherals, cables, and so on

Hz hertz—per second, as in cycles per second or samples per second

Iex excitation current

IEC International Electrotechnical Commission

IEEE Institute of Electrical and Electronics Engineers

in. inches

inductance the relationship of induced voltage to current

input bias current the current that flows into the inputs of a circuit

input impedance the measured resistance and capacitance between the input terminals of a

circuit

Installation Category

(Overvoltage Category) classification system for expected transients on electrical supply

installations

instrument driver a set of high-level software functions that controls a specific plug-in DAQ

board. Instrument drivers are available in several forms, ranging from a

function callable language to a virtual instrument (VI) in LabVIEW.

interrupt a computer signal indicating that the CPU should suspend its current task

to service a designated activity

interrupt level the relative priority at which a device can interrupt

I/O input/output—the transfer of data to/from a computer system involving

communications channels, operator interface devices, and/or data

acquisition and control interfaces