Navigation for Capacitor Terms
"A", "B/C", "D", "E", "F", "G", "I/L",
"M/N", "P", "Q/R", "S", "T", "V/Z"

Impedance (Z): Total opposition offered to the flow of an alternating or pulsating current, measured in ohms. (Impedance is the vector sum of the resistance and the capacitive reactance, i.e., the complex ratio of voltage to current.)

Impregnant: A substance, usually liquid, used to saturate paper dielectric and to replace the air between its fibers. (Impregnation increases the dielectric strength and the dielectric constant of the assembled capacitor.)

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.

Insulation resistance (IR): Direct current resistance between two conductors that are separated by an insulating material. IR can be measured across the terminals of the capacitor. Refer here for an example graph of Capacitor Insulation Resistance.

Insulating Sleeve: A non-conductive sleeve placed around the body of a capacitor.
Insulated Capacitor
Capacitor Insulated Sleeve

Insertion-Loss: Insertion-Loss may be tested per MIL-STD-220. Refer here for an example graph of Capacitor Insertion-Loss.

Leaded: Not surface mount. Capacitors which have wire leads instead of pads as in Surface Mount Devices [SMD]. Common leaded styles include; Radial Lead, Axial Lead, and Snap-in devices. Leaded components are through-hole devices, their leads pass through the PWB. Leaded capacitors are available in many different body shapes or styles.

Radial Lead Through Hole Capacitor
Leaded Capacitor

Leakage Current: The small current [IL] that always flows through a capacitor based on the insulation resistance of the device. This is the residual current which continues to flow when the capacitor has been charged up to a set voltage. At this voltage it's magnitude is determined by the thickness (formation voltage), the degree of perfection of the dielectric oxide layer, and the foil surface area. The value of leakage current will continue to fall while voltage is applied, until a very low steady state value is reached. It's value will increase both with voltage and temperature. The longer capacitors are stored with no applied voltage, the higher the initial leakage current.

Leakage Resistance: The electrical resistance that opposes the flow of current through the dielectric of a capacitor. The higher the leakage resistance, the slower the capacitor discharges or leaks across the dielectric.

LICC: Low Inductance Chip Capacitor. A chip capacitor that has the electrodes on the long side of the chip instead of the short side. A normal 1206 package becomes an 0612, a 0805 becomes a 0508, a 0603 becomes an 0306. Graphic at right.

Low Inductance Chip Capacitor LICC Package
LICC Package Style

Refer to the Low Inductive Chip Size page.

Life: The life of a capacitor, in general, decreases with an increase in temperature. Life as a function of operating temperature is a complex function and should be determined from life-test data. In the absence of this data, the familiar 100C rule for a chemical reaction may be used as a rough approximation. This rule states that the life decreases by a factor of two for each 100C rise in temperature. This rule, however, should never be used outside of the temperature range specified by the manufacturer, since chemical reactions of an entirely different nature may take place at extreme temperatures. This rule should not be applied to liquid and gaseous dielectric without further investigation. Refer to Aging.

Liquid-Filled: A capacitor in which a liquid impregnant occupies substantially all of the case volume not required by the capacitor element and its connections. (Space may be allowed for the expansion of the liquid under temperature variations}.

Liquid-Impregnated: A capacitor in which a liquid impregnant is dominantly contained within the foil-winding and paper-winding, but does not occupy substantially all of the case volume.

Load Life: See Life, also called Life expectancy. Note that in some cases Load Life is given at the maximum operational temperature, so the actual life may be greatly increased when operating at a temperature below the maximum.

LTCC: Low Temperature Co-fired Ceramic, Ceramic Chip Capacitors.

Lumped Capacitance: Text in review.

Lumped Capacitance Load Derating Curve
Lumped Capacitance
PC motherboard

Distributor rolodex Electronic Components Electronic Equipment EDA CDROM Software Engineering Standards, BOB card Cabled Computer Bus Electronic Engineering Design Table Conversion DB9-to-DB25.
DistributorsComponents Equipment Software Standards Buses Design Reference