Home > Crystal Glossary > E

Crystal and frequency control glossary

Numeric | A | B | C | D | E | F | G | H | I | J | K
L | M | N | O | P | Q | R | S | T | U | V | W | XYZ

Earth station

A station located either on the Earth's surface or within the major portion of the Earth's atmosphere and intended for communication:

with one or more space stations; or

with one or more stations of the same kind by means of one or more reflecting satellites or other objects in space.

ECL

Abbreviation for emitter-coupled logic.

EEPROM

Abbreviation for electrically erasable programmable read-only memory.

EIA

Abbreviation for Electronic Industries Association.

Electrode capacitance

This capacitor is not a result of the acoustic vibration of the crystal blank but rather a simple capacitor formed by a dielectric with electrodes on either side.

Electrodes

Terminal through which electric current passes between metallic and nonmetallic parts of an electric circuit. In most familiar circuits current is carried by metallic conductors, but in some circuits the current passes for some distance through a nonmetallic conductor.

Electromagnetic compatibility (EMC)

The condition which prevails when telecommunications equipment is performing its individually designed function in a common electromagnetic environment without causing or suffering unacceptable degradation due to unintentional electromagnetic interference to or from other equipment in the same environment.

Electromagnetic interference (EMI)

An engineering term used to designate interference in a piece of electronic equipment caused by another piece of electronic or other equipment. EMI sometimes refers to interference caused by nuclear explosion.

Electromagnetic spectrum

The range of frequencies of electromagnetic radiation from zero to infinity. Note: The electromagnetic spectrum was, by custom and practice, formerly divided into 26 alphabetically designated bands. This usage still prevails to some degree. However, the ITU formally recognizes 12 bands, from 30 Hz to 3000 GHz. New bands, from 3 THz to 3000 THz, are under active consideration for recognition.

Emission

In this context, radiation produced by a radio transmitting station.

Emitter

A transistor region from which charge carriers that are minority carriers in the base are injected into the base, thus controlling the current flowing through the collector; corresponds to the cathode of an electron tube.

Energy trapping

A term applied to the application of the cutoff phenomenon in wave guides to suppress undesired modes of vibration in a quartz crystal unit.

Equivalent circuit

The equivalent circuit shown below depicts electrical activity of a quartz crystal unit operating at its natural resonant frequency. The CO, or shunt capacitance, represents the capacitance of the crystal electrodes plus the capacitance of the holder and leads. R1, C1, and L1 compose the "motional arm" of the crystal, and are referred to as the motional parameters. The motional inductance (L1) represents the vibrating mass of the crystal unit. The motional capacitance (C1) represents the elasticity of the quartz, and the resistance (R1), represents bulk losses occurring within the quartz.

Equivalent series resistance (ESR)

(1) The resistive element, measured in ohms, of a crystal device. The ESR measurement is made only at the series resonant frequency (FS), not at some predetermined parallel resonant frequency (FL). The motional inductance (L1) and motional capacitance (C1) are of equal ohmic value but are exactly opposite in phase. The net result is that they cancel one another and only a resistance remains in the series leg of the above equivalent circuit. Crystal resistance measured at some parallel load resonant frequency is often called the "effective" resistance. (2) A term used to define and quantify the resistive element of a crystal.

ESD

Abbreviation for electrostatic discharge.

Etch

A process used in the manufacture of some types of crystal units. The etch process results in an improved surface condition and an increase in the frequency of a blank. The word "etch" is also used to describe the material used in the etch process, as well as the process itself.

ETSI

Abbreviation for European Telecommunications Standards Institute. A European counterpart to ANSI. It facilitates integration of telecommunications standards into all of Europe.

Extremely high frequency (EHF)

Frequencies from 30 GHz to 300 GHz.

Extremely low frequency (ELF)

Frequencies from 30 Hz to 300 Hz.

Numeric | A | B | C | D | E | F | G | H | I | J | K
L | M | N | O | P | Q | R | S | T | U | V | W | XYZ

If you would like us to suggest a definition for our crystal and frequency control glossary, please use our contact form or email us at info@icmfg.com to see how you may benefit from using International Crystal's frequency control products and services.

International Crystal Manufacturing
10 North Lee Avenue • Oklahoma City, OK 73102
Toll Free Phone: 1-800-725-1426 • Toll Free Fax: 1-800-322-9426
Phone: 1-405-236-3741 • Fax: 1-405-235-1904
Email: info@icmfg.com