Electronic Engineering Dictionary, "I"

Indexed Address. An address that is altered by the content of an index register.

Index of Refration. The degree of bending of an RF wave when passing from one medium to another.

Indirectly Heated Cathode. Same as the directly heated cathode with one exception: The hot filament raises the temperature of the sleeve around the filament; the sleeve then becomes the electron emitter.

Induce. To cause an electrical or magnetic change in one circuit by changing the condition in another circuit.

Induced-Channel MOSFET. A MOSFET in which there is no actual channel between the source and the drain. This MOSFET is constructed by making the channel of the same type of material as the substrate.

Induced Charge. An electrostatic charge produced on an object by the electric field that surrounds a nearby object.

Induced Current. Current caused by the relative motion between a conductor and a magnetic field.

Induced Electromotive Force. The electromotive force induced in a conductor because of the relative motion between the conductor and a magnetic field.

Induced Voltage. See Induced Electromotive Force.

Inductance. The property of a circuit that tends to oppose a change in the existing current flow. The symbol for inductance is L.

Inductance Bridge. An ac bridge circuit used to measure an unknown value of inductance.

Induction. The act or process of producing voltage and current by the relative motion of a magnetic field across a conductor.

Induction Field. The electromagnetic field that is produced about an antenna when current and voltage are present on the same antenna.

Induction Generator. A induction motor operated as an ac generator.

Induction losses. The losses that occur when the electromagnetic field around a conductor cuts through nearby metallic objects and induces a current into that object.

Induction Motor. A simple ac motor. A motor in which the rotor is energized by transformer action (induction) from the stator. Induction motors are used more than any other type. [Motor Manufacturers]

Inductive Coupling. The transfer of energy from one circuit to another by virtue of the mutual inductance between the circuits. Coupling of two coils by means of magnetic lines of force. In transformers, coupling applied through magnetic lines of force between the primary and secondary windings.

Inductive Kick. A large voltage produced by the collapsing field of a coil when the current is stopped.

Inductive load. A load that contains a large amount of inductance, or a load that is more inductive than capacitive or resistive. A load in which the AC current lags the voltage. A relay, motor, coil [shown to the right] or other device which is primarily inductive.

Inductive Reactance. The opposition to the flow of an alternating current caused by the inductance of a circuit, expressed in ohms. Identified by the symbol XL. Inductive reactance = 2 x 3.14 x F X L [2 x pie x frequency x Inductance].

Inductor. A 2-terminal passive device having a coil of wire wound wrapped around a core [which may be magnetic metal or air] to produce a high inductance in the wire.

Industrial Control Circuit Transformer. See Control Circuit Transformer.

Industrial Control Transformers. See Control Circuit Transformer.

Industrial Temperature Range. -40 to 85 degrees Celsius. A temperature range developed for equipment operating in harsh environments. Comparison of Operational Temperature Ranges].

Inertia. The physical tendency of a body in motion to remain in motion and a body at rest to remain at rest unless acted upon by an outside force.

Infinite. Extending indefinitely, endless. Boundless, having no limits. An incalculable number.

Infra-low Frequency. The band of frequencies from 300 Hz to 3,000 Hz.

Infrared. [IR] The region of the electromagnetic spectrum bounded by the long-wavelength extreme of the visible spectrum (approximately 0.7 um) and the shortest microwaves (approximately 0.1 mm).

Infrared Emitting Diode. A Light Emitting Diode that produces an output in the Infrared spectrum when current is applied. A common peak wavelength for an IR diode is 950nm, but also goes down to 830nm.

Infrasonic. Sounds below 15 Hz. [Subsonic].

Inhibit. An input line to digital ICs that stop the IC from performing a function.

Injection Laser Diode. [ILD] A Laser Diode. A laser that uses a forward-biased semiconductor junction as the active medium.