IC - Abbreviation for "integrated circuit"
IC voltage regulator - Three terminal device used to hold the output voltage of a power supply constant over a wide range of load variations.
IGFET - Insulated gate field effect transistor. Another name for a "MOSFET."
impedance - (Z) Measured in ohms it is the total opposition to the flow of current offered by a circuit. Impedance consists of the vector sum of resistance and reactance.
impedance coupling - Coupling of two signal amplifier circuits through the use of an impedance such as a inductor.
impedance matching - Matching the output impedance of a source to the input impedance of a load to attain maximum power transfer.
incandescence - State of a material when heated to the point where it emits light. (red hot or white hot).
induced voltage - Voltage generated in a conductor when subjected to a moving magnetic field.
inductance - Property of a circuit to oppose a change in current. The moving magnetic field produced by a change in current causes an induced voltage to oppose the original change.
inductive circuit - Circuit having greater inductive reactance than capacitive reactance.
inductive reactance - Opposition to the flow of AC current produced by an inductor. Measured in Ohms and varies in direct proportion to frequency.
inductor - Length of conductor used to introduce inductance into a circuit. The conductor is usually wound into a coil to concentrate the magnetic lines of force and maximize the inductance. While any conductor has inductance, in common usage the term inductor usually refers to a coil.
infrared - Electromagnetic heat radiation whose frequencies are above the microwave frequency band and below red in the visible band.
inhibit - To stop an action or block data from passing.
in phase - When two or more waves of the same frequency have their positive and negative peaks occurring at the same time.
input impedance - Opposition to the flow of signal current at the input of a circuit or load.
insulated - When a non conducting material is used to isolate conducting materials from one another.
insulating material - Material that will prevent the flow of current due to its chemical composition.
insulation resistance - Resistance of insulating material. The greater the insulation resistance, the better the insulation.
integrated - When two or more components are combined into a circuit and then incorporated into a single package.
integrator - A device that approximates and whose output is proportional to an integral of the input signal. A low pass filter.
intermediate frequency amplifier - In a super heterodyne radio it amplifies a fixed frequency lower than the received radio frequency and higher than the audio frequency.
intermittent - A fault occurring at random intervals of time. Intermittent problems are often difficult to locate because of the random nature. They often don't occur when the technician is present.
internal resistance - Every source has some resistance in series with the output current. When current is drawn from the source some power is lost due to the voltage drop across the internal resistance. Usually called output impedance or output resistance.
intrinsic material - A semiconductor material with electrical properties essentially characteristic of ideal pure crystal. Essentially silicon or germanium crystal with no measurable impurities.
intrinsic stand-off ratio - A unijunction transistor (UJT) rating used to determine the firing potential of the device.
inverting amplifier - An amplifier that has a 180° phase shift from input to output.
inverting input - In an operational amplifier (op amp) the input that is marked with a minus sign. A signal applied at the inverting input will be given 180° phase shift between input and output.
ion - An atom with fewer electrons in orbit than the number of protons in the nucleus is a positive ion. An atom with a greater number of electrons in orbit than the number of protons in the nucleus is a negative ion.
ionized - Atoms become ionized when they gain or lose a valence electron.