|Nanovolt||Nanovolt (nV): Unit of measure. A billionth of a volt.|
|NC||Normally closed (switch contacts)|
|NIC||Network interface card|
|Nickel Metal Hydride||See NiMH|
|NiMH||Nickel metal hydride: A rechargeable-battery technology.|
|nMOS||An n-channel metal-oxide semiconductor (nMOS) transistor is one in which n-type dopants are used in the gate region (the "channel"). A positive voltage on the gate turns the device on.|
|NO||Normally open (Switch contact)|
|Non Return To Zero||See NRZ|
|Non-Interruptible Power Supply||See Battery Backup|
|Non-Volatile Power Supply||See Battery Backup|
|Nonvolatile||Nonvolatile (NV) RAM is memory which retains its stored value when power is removed.|
|Nonvolatile Memory||See Nonvolatile|
|Norton amplifier||See Transimpedance Amplifier|
|Noxious Fumes||A combination of inert and corrosive gases usually associated with exhaust fumes or industrial by-products gases which can cause corrosive effects on temperature and pressure sensors when exposed.|
|NRE||Nonrecurring engineering — one-time engineering costs associated with a project.|
|NRZ||Non Return to Zero: A binary encoding scheme in which ones and zeroes are represented by opposite and alternating high and low voltages, and where there is no return to a zero (reference) voltage between encoded bits. That is, the stream has only two values: low and high.|
|NTC||Negative temperature coefficient|
|nth||A tiny, tiny amount. Pronounced "enth." From 1/n, which is one "nth."|
|NTSC||NTSC is the color television standard established by the National Television Standards Committee in the United States in 1953. The NTSC standard's distinguishing feature was that it added color to the original 1941 black and white television standard in such a way that black and white TVs continued to work.
(Another distinguishing characteristic was that NTSC's dependency on accurate phase meant that it was difficult to maintain the color as the signal was transmitted and processed. Television engineers often joke that NTSC stands for "Never Twice the Same Color.")
The NTSC standard adds a color subcarrier which is quadrature-modulated by two color-difference signals and added to the luminance signal. The genius of the system is that black and white TVs ignore the color components, which are beyond the black and white signal's bandwidth.
The NTSC color subcarrier reference is 3.579545MHz. The horizontal sync rate (H) was adjusted slightly from the black and white standard's 15.750kHz such that the color subcarrier is 455/2 times H. The vertical rate is Fv = Fh x 2/525.
See: Video Basics.
|NV Memory||See Nonvolatile|
|Nyquist||In A/D conversion, the Nyquist principle (derived from the Nyquist-Shannon sampling theorem) states that the sampling rate must be at least twice the maximum bandwidth of the analog signal in order to allow the signal to be reproduced. The maximum bandwidth of the signal (half the sampling rate) is commonly called the Nyquist frequency (or Shannon sampling frequency).
In real life, sampling rate must be higher than that (because filters are not perfect). As an example, the bandwidth of a standard audio CD is a bit shy of the theoretical maximum of 22.05kHz (based on the sample rate of 44.1kHz).