electro-, electr-, electri-

1. The total amount of polarization (dipole moment) caused by the movement of electrons within an atom.
2. The magnetic dipole moment which an electron possesses by virtue of its spin.
3. The total magnetic dipole moment associated with the orbital motion of all the electrons of an atom and the electron spins.

This is opposed to a nuclear magnetic moment.

1. A computer-system communications service in which text messages are sent to a central computer or over a network and retrieved by the addressee.
2. The electronic transmission of letters, messages, and memos via a communications network; now more often via computer connections.
3. A system for sending messages by computer, Telex, facsimile telegraph, or other electronic means instead of by post.
4. Messages sent by one user of a computerized communications system and retrieved almost instantly by other users.

The messages may be transmitted with a modem through telephone lines or, in some cases, by shortwave radio and it can be in many forms, including mailgrams, twx, and facsimile transmission devices.

A megaphone that has a microphone, an audio amplifier, and a horn loudspeaker all developed into a single unit.

An electronic instrument for measuring and indicating small linear distances in air or across nonmetallic materials.

1. A mechanism that depends for its operation on the generation of a voltage by the motion of one of the electrodes in a special electron tube.
2. A microphone whose vibrations or sound waves act on one of the electrodes in an electron tube.

1. A procedure in which electrons released from microscopic irradiated objects are used to produce a photographic image.
2. Microradiography of very thin specimens in which the emission of electrons from an irradiated object, either the specimen or a lead screen behind it, is used to produce a photographic image of the specimen, which is then enlarged.

Microradiography is a technique for the study of surfaces of solids by monochromatic-radiation (such as X-ray) contrast effects shown by means of projection or enlargement of a contact radiograph.

1. An electromagnetic instrument designed, to locate, or to detect explosive mines.
2. An electronic tool which indicates the presence of metallic or nonmetallic explosive mines under the ground or hidden in the water.

Electronically driven equipment which will constantly monitor the physiological status of patients and the effects of those medical interventions on the patients.

Such mechanisms should relieve hospital staff of time-consuming "human monitoring" procedures and in some cases they will enable patients to carry monitoring devices during their daily living activities.

Such instruments would make regular assessments of blood-sugar concentration in patients with diabetes mellitus (metabolic disorder affecting blood sugar levels) or process the routine checking of the blood or tissue concentrations of administered drugs.

1. An electronic instrument which adjusts the speed of a DC (direct current) motor when it is driven by an AC (alternating current) power line.
2. A control circuit used to change or to vary the speed of a direct-current (DC) motor operated from an alternating-current (AC) power line.

Silicon controlled rectifiers or power transistors rectify or correct the voltage and vary the field current of the motor.

1. An instrument that uses semiconductors or electron-tube circuits to measure resistance, electric current, and voltage.
2. A multimeter that uses semiconductor or electron-tube circuits to drive a conventional multiple-scale meter.
3. An apparatus that employs the characteristics of an electron-tube circuit for the measurement of electrical quantities, at least one of which is voltage or current, or a single calibrated scale.

When a digital display replaces the moving-coil meter, it is called a "digital multimeter".

An audio signal processor which contains sound generators (oscillators) and additional circuitry; such as, filters to produce familiar sounds including those produced by conventional musical instruments, or to create unique sounds and effects.

1. A musical instrument in which an audio signal is produced by a pickup or audio oscillator and amplified electronically to feed a loudspeaker; such as, in an electric guitar, electronic carillon, electronic organ, or electronic piano.
2. A musical device that generates sounds electronically.

1. The use of electronic aids to determine the position and to direct the course of a craft; such as, aircraft or water craft.
2. Navigation by means of any electronic device or instrument.
3. A means of determining a geographical position using electronic instruments, principally satellite navigation equipment.

The use of video cameras, recording, and other supporting electronic gear to collect news stories for TV airing.

1. A device hat transmits a signal with a white noise component (noise of equal intensity over a wide range of frequencies) in order to prevent the functioning of a radar system.
2. An electronic jammer (causing interference) that emits a radio-frequency carrier modulated with a white noise signal (noise of mixed frequency) usually derived from a gas tube; used against military enemy radar.