electro-, electr-, electri-

(Greek > Latin: electric, electricity; from amber, resembling amber, generated from amber which when rubbed vigorously [as by friction], produced the effect of static electricity)

Electronics in our lives consists of numerous tools

Equipment which we use everyday relies on electronics to function including calculators, car controls, cameras, washing machines, medical scanners, mobile telephones, radar systems, computers; as well as many other applications or devices which are listed in this unit.

electromotive force, EMF
1. The pressure that causes electrons to move in an electrical circuit, measured as the amount of energy supplied by an electric current passing through a given source, as measured in volts.
2. The electric potential, or ability of electric energy to perform work.

Electromotive force is usually measured in joules per coulomb, or volts; and the higher the voltage, the greater the potential of electric energy.

Any device; such as, a storage battery, that converts some form of energy into electricity is a source of electromotive force or EMF or emf; or, a generator produces an electromotive force.

3. The difference in electric potential, or voltage, between the terminals of a source of electricity; such as, a battery from which no current is being drawn. When current is drawn, the potential difference drops below the emf value.
4. The force that causes a flow or the movement of electrons through an electrical circuit.

It is the amount of energy derived from an electric source in one second when one unit of current is passing through the source, commonly measured in volts.

Electromotive force is produced by differences in electrical charge or potential.

5. Energy per unit electric charge that is imparted by an energy source; such as, an electric generator or a battery.

When the device does work on the electric charge being transferred within itself, energy is converted from one form to another.

electromotive series, electrochemical series, galvanic series
1. The classification of metals in the order of their electrode potentials.
2. A serial arrangement of metallic elements or ions according to their electrode potentials determined under specified conditions; the order shows the tendency of one metal to reduce the ions of any other metal below it in the series.
3. A series in which the metals and other substances are listed in the order of their chemical reactivity or electrode potentials, the most reactive at the top and the less reactive at the bottom.
4. A tabulation on which various substances; such as, metals or elements, are listed according to their chemical reactivity or standard electrode potential.

It is usually ordered with increasing standard electrode potentials (most negative on top).

For metals, the order indicates the tendency to spontaneously reduce the ions of any other metal below it in the series.

During electrolytic reduction of cations (for example, electroplating) an element lower in the series (more positive) will deposit first, and an element higher in the series (more negative) will deposit only when the solution is practically depleted of the ions of the first element.

The production of a flow of electricity.
An early form of a receiver for a telephone, invented by Thomas Alva Edison (1847-1931), an American inventor who patented more than a thousand inventions, among them the microphone (1877), the phonograph (1878), and an incandescent lamp (1879).

In New York City, he installed the world's first central electric power plant (1881-1882).

1. A machine producing electric current.
2. A motor run by electricity.
electromuscular sensibility
The responsiveness of muscles to electric stimulus.
electromyogram, EMG
1. A graphic record of the contraction of a muscle as a result of electrical stimulation or the electric activity of a muscle either spontaneous or in response to artificial electric stimulation.
2. A record of the spiking electrical discharge of a muscle, motor unit, or muscle fiber generated in response to neutral impulses or arising spontaneously.
3. A record of eye movements when reading, obtained by measuring the potential difference between an electrode placed at the center of the forehead and one placed at the temple.
4. A record of the intrinsic electric activity in a skeletal muscle.

Such data aid the diagnosis of neuromuscular problems and are obtained by applying surface electrodes or by inserting a needle electrode into the muscle and observing electric activity with an oscilloscope and a loudspeaker.

Some electromyograms show abnormalities; such as, spontaneous electric potentials within the muscle under study, and help pinpoint lesions of motor nerves.

Electromyograms also measure electric potentials induced by voluntary muscular contraction.

1. A machine used for producing a graphical tracing of the electrical activity picked up via electrodes inserted into muscle tissue which is used to diagnose muscular ailments.

It consists of an amplifier, an electrically activated trace-drawing pen, and a moving strip of paper.

2. An instrument which records differences in the electric potential of muscles that is used to diagnose muscular ailments.

Similar to the electrocardiograph, the electromyograph picks up clicks from sick muscles.

Having to do with, referring to, or made by an electromyograph which is a tool which records differences in the electric potential of muscles.
electromyographic biofeedback
A therapeutic procedure that uses electronic or electromechanical instruments to measure, process, and feed back reinforcing information with auditory and visual signals accurately.

It is used to provide information about muscle activity during ambulation, for example, in patients with brain injury, stroke, or cerebral palsy.

electromyographic technician
A health-care provider with special training and experience to assist the physician in recording and analyzing muscle action potentials with the use of various electronic devices.
electromyography of pelvic floor sphincter
An electrodiagnostic test performed to evaluate the neuromuscular function of the urinary or anal sphincter (circular muscle that constricts a passage or closes a natural opening).

It is done most often in patients with urinary or fecal incontinence.

electromyography, EMG
1. The recording of electrical activity generated in muscles for diagnostic purposes; both surface and needle recording electrodes can be used, although characteristically the latter is employed, so that the procedure is also called needle electrode examination.
2. An umbrella term for the entire electrodiagnostic study performed in the EMG laboratory, including not only the needle electrode examination, but also the nerve conduction studies.
3. A diagnostic procedure in which metal probes are attached to or inserted into the skin in order to detect the electrical activity of contracting muscles.

Such activities are altered in recognizable ways by diseases that affect either muscles or nerves which supply the muscles.

4. The preparation, study of, and interpretation of electromyograms.
5. The recording of electrical activities associated with muscular functions, often used in the clinical diagnosis of muscular disorders.

A single electrical spike potential is generated when a muscle fiber contracts while the magnitude of the spike potentials is roughly proportional to the amount of muscular tension.

Surface detecting electrodes (for many muscle fibers) or needle electrodes (for one or a few fibers) provide a signal that is amplified and displayed on a cathode-ray tube.

A procedure for testing and recording neuromuscular activity by electric stimulation of nerves.

Needle electrodes are inserted into any skeletal muscle being studied, electric current is applied to the electrodes, and neuromuscular functions are observed and recorded by means of instruments; such as, a cathode-ray oscilloscope and an appropriate recording device.

The procedure is helpful in the study of neuromuscular conduction, the extent of nerve lesions, and reflex responses.

electron (s), electrons (pl)
1. A stable elementary particle that is a primary constituent of ordinary matter, contained in the atoms of all elements.

Electrons flowing in a conductor constitute an electric current.

2. A negative beta particle emitted from a radioactive substance.
3. A negatively charged elementary particle that has a specific charge, mass, and spin.

The number of electrons associated with the nucleus of an atom is equal to the atomic number of the substance.

4. A sub-atomic particle with a negative beta particle emitted from a radioactive substance.

A flow of electrical current consi that are in a given material, the greater its electrical conductance (or equivalently, the lower its resistance).

Electrons are the primary charge carriers in electric currents.

All atoms have electrons arranged around a nucleus and an electron may be positive (positron), but as the term is generally used, it refers to the negative form (negatron).

The references or sources of information for compiling the words and definitions in this unit are listed at this Electronic Bibliography page or specific sources are indicated when they are appropriate.

A cross reference of word units that are related, directly and/or indirectly, with "electricity": galvano-; hodo-; ion-; piezo-; -tron; volt; biomechatronics, info; mechatronics, info.