Electronic Engineering Glossary Terms

In Phase. Applied to the condition that exists when two waves of the same frequency pass through their maximum and minimum values of like polarity at the same instant. Voltage and current are in-phase across a resistor but out of phase in a capacitor or Inductor. Note the maximum value of the current wave or voltage may be any value, as long as they reach their maximum point at the same time.

Input. The current, voltage, power, or driving force applied to a circuit or device. The input signal applied to an IC.

Input End. The end of a two-wire transmission line that is connected to a source.

Input Impedance. The impedance that a circuit sees looking into a circuit's input. Impedance presented to the transmitter by the transmission line and its load.

Input Offset Voltage. The voltage that must be applied to the inputs of an Opamp to produce zero volts at the output. A related term is Off-Set Null.

Input/Output. [I/O] Pertaining to either input or output or both, especially in data processors. A device that introduces data into or extracts data from a system.

Input Protection. For analog input channels, protection against over-voltages that may be applied between any two input connectors or between any input connector and ground.

Input Resistance. The ration of the change of input voltage to the change in input current.

Inrush Current. A higher current that occurs when a device is first turned on, or when first connected to a circuit. A surge current that occurs only during an initial brief time while a component stabilizes or warms up [in the case of a lamp].

Insertion Force. The effort, usually measured in ounces, required to engage mating components [connectors, ICs and sockets].

Insertion Gain. The gain resulting from the insertion of a device in a transmission line, expressed as the ratio of the signal power delivered to that part of the line following the device to the signal power delivered to that same part before insertion.

Insertion Loss. The difference in power level between a device being inserted in the transmission path and, not being inserted in the transmission path. The loss resulting from the insertion of a device in a transmission line, expressed as the reciprocal of the ratio of the signal power delivered to that part of the line following the device to the signal power delivered to that same part before insertion. Insertion loss is usually expressed in dB.

Instantaneous Amplitude. The amplitude at any given point along a sine wave at a specific instant in time.

Instantaneous Automatic Gain Control. [IAGC] A circuit that can vary the gain of the radar receiver with each input pulse to maintain a nearly constant output peak amplitude.

Instantaneous Value. The magnitude at any particular instant when a value is continually varying with respect to time.

Instrumentation Amplifier. A differential amplifier utilizing an input buffer on both the positive and negative input lines and having a single output. This example uses operational amplifies and its associated resistors required to produce gain. Unlike an Op Amp there is no gain setting resistor between the input and output terminals.

Instrumentation Amplifier

Instrument Transformer. A transformer that receives high voltages or current and translates that into low voltages and current for use by a measuring instrument.

Insulated. Separated from other conducting surfaces by a dielectric (including air space) offering a high resistance to the passage of current. Note: When any object is said to be insulated, it is understood to be insulated for the conditions to which it is normally subjected. Otherwise, it is, uninsulated.

Insulated Gate. A term used with either bipolar transistors [IGBT] or field effect transistors [IGFET] to indicate that the devices have an Insulated Gate. In the case of the Insulated Gate Bipolar Transistor the device has a Gate and not a Base. Example IGBT 2N7364. An Insulated-Gate FET has one or more gate electrodes which are electrically insulated from the channel.

Insulation. A material used to prevent the leakage of electricity from a conductor and to provide mechanical spacing or support as protection against accidental contact with the conductor. A material that does not conduct electricity easily.

Insulation Displacement Connection. [IDC] A connector that cuts through the insulation of a conductor to make contact with the wire. Detailed definition of an IDC Connector. [Example IDC Connector]

Insulation Resistance. The resistance offered by an insulating material to current leakage. The resistance between two electrical conductors.

Insulating Material. A material defined as having a volume resistivity of 10¹² ohm-cm minimum, or a surface resistivity of 10¹⁴ ohms/square minimum.

Insulator. Material of such low conductivity that the flow of current through it can usually be neglected. A device having high electrical resistance; used for supporting or separating conductors so as to prevent undesired flow of current from the conductors to other objects. Glass or ceramic materials are commonly used insulators.

Insulator