Electronic Engineering Glossary Terms

Noble Gas. An inert gas.

Node. A connection point in a circuit or on a bus. The electronics connected to a network via a single drop. The fixed minimum points of voltage or current on a standing wave or antenna. A junction or branch.

Noise. Unwanted electrical signals. In reference to sound, an unwanted disturbance caused by spurious waves that originate from man-made or natural sources. In radar, erratic or random deflection or intensity of the indicator sweep that tends to mask small echo signals. Thermal noise, crosstalk, leakage currents, switching transients. An undesired disturbance within the frequency band of interest; the summation of unwanted or disturbing energy introduced into a communications system from man-made and natural sources.

Noise Bandwidth. Text in review.

Noise Factor. The ratio of the total noise power delivered to the load to the noise power that would be delivered to the load if the only output noise component were due to the thermal noise of the input source resistance at a temperature of 290 K.

Noise Figure. The ratio of output noise to input noise in a receiver. The ratio of the output noise power of a device to the portion thereof attributable to thermal noise in the input termination at standard noise temperature (usually 290 K). The common logarithm of the ratio of the input signal to noise ratio to the output signal to noise ratio. Noise factor expressed in decibels. At a selected input frequency, the noise figure is the ratio of the total noise power per unit bandwidth (at a corresponding output frequency) delivered to the output termination, to the portion thereof contributed at the input frequency by the input termination, whose noise temperature is standard (293K) at all frequencies.

Noise Level. The noise power, usually relative to a reference.

Noise Limiter. Circuit that clips the peaks of the noise spikes in a receiver.

Noise Margin. The noise margin in digital logic is the difference between the maximum output of an IC compared to the minimum input the receiving IC will accept as a logic level. Read more on Noise Margin Details. The voltage amplitude of extraneous signal which can be algebraically added to the noise-free worst-case "input" level before the output voltage deviates from the allowable logic voltage levels. The term "input" is used here to refer to logic input terminals, power supply terminals, or ground reference terminals.

Noise Suppressor. See Noise Limiter.

Noise Voltage. Interfering and unwanted voltage in an electronic device or system. The diagram shows a noise voltage test circuit for an OpAmp, single or split supply voltage.

No-Load Condition. The condition that exists when an electrical source or secondary of a transformer is operated without an electrical load.

Nominal Bandwidth. The widest band of frequencies, inclusive of guard bands, assigned to a channel.

Nomograph. An alignment chart that solves equations graphically.

Non-conductor. An insulator. A material that does not conduct current.

Nondegenerative Parametric Amplifier. A parametric amplifier that uses a pump signal frequency that is higher than twice the frequency of the input signal.

Nondirectional. See Omidirectional.

Non-Inductive. A component that only has a negligible inductance.

Non-Inductive load. A resistive load. A load that only contains resistive and or capacitive elements.

Non-Inverting Amplifier. An amplifier that does not invert the incoming signal at the output. The circuit example shows a Non-inverting Op Amp.

Non-Inverting Op-Amp

Nonlinear Device. A device in which the output does not rise and fall in direct proportion to the input. [Nonlinear Resistors].

Nonlinear Distortion. Distortion that results from operating an amplifier in a non-linear manner. Distortion caused by a deviation from a linear relationship between specified input and output parameters of a system or component.

Nonlinear Impedance. An impedance in which the resulting current through the device is not proportional to the applied voltage.

Non-Maskable Interrupt. [NMI] An interrupt which is not covered by the interrupt mask bit contain in a [condition code] register. An interrupt that may not be ignored by a processor. Also see Interrupt.

Nonrepairable. A system or assemble that can not be repaired. Sub-assemblies of high reliability or relatively low cost shall be constructed as non-repairable [MIL-E-5400].

Nonresonant Line. A transmission line that has no standing waves of current or voltage. A transmission line terminated in its characteristic impedance. A transmission line that passes all its energy to the load.

Non-Return to Zero. [NRZ] A data encoding method that sends a '1' as a high and a '0' as a low. Refer to the Data Encoding Dictionary section of the site.

Non-Saturated Logic. A type of digital logic that prevents the transistors within the logic gates from reaching saturation, allowing the transistors to turn on and off faster, allowing the gates to operate faster. See Emitter Coupled Logic.

Non-Shorting Switch. A Break before Make switch.

Nonsynchronous. One system or component having no relationship to the clocking, timing or phase of another system.

Non-Threshold Logic. [NTL] A logic family [obsolete] that mixes Resistor-Transistor Logic [RTL] and Emitter Complied Logic [ECL].

Non Trip-Free Circuit Breaker. A circuit breaker that can be held in the ON position during an over-current condition. Circuit Breakers

Non-Volatile Memory. A type of memory that retain its stored contains even when no power is applied.

Non-Volatile Storage. A type of storage that retains its contains even with no power, as in tape drives or hard drives.

Non-Wire Wound Resistor. A variable resistor does not use wire as the resistive element. Refer to the Resistor Dictionary section of the site.

No Operation [Instruction]. NoOp [NOP] No Operation Performed. A microcomputer instruction to do nothing.

NOR. A logic function of A and B that is true if both A and B are false.

NOR GATE. An OR gate that is followed by an inverter to form a binary circuit in which the output is a logic 0 if ANY of the inputs is a logic 1 and the output is a logic 1 only if all the inputs are a logic 0. For more information refer to the entry regarding a NOR Gate.

Normal. The imaginary line perpendicular to the point at which the incident wave strikes the reflecting surface. Also called the perpendicular.

Normally Closed. [NC] The condition of the contacts of a switch or relay that are at rest in the closed position.

Normally Open. [NO] The condition of the contacts of a switch or relay that are at rest in the open position.

Norton Amplifier. A current mode amplifier such as an LM3900 or LM359 Op Amp. In reference to the Norton equivalent of a current source.