Look up: Impedance

1. 
   Impedance
   Impedance is the total opposition offered by a circuit to the flow of alternating current.
   Found on http://www.encyclo.co.uk/nol.php
   
   
2. 
   Impedance
   The measure of resistance to alternating current in an electrical circuit. Measured in 'ohms'. An important characteristic in many audio components such as speakers and microphones.
   Found on http://www.dramatic.com.au/glossary/glos
   
   
3. 
   Impedance
   A property of all metallic and electrical conductors that describes the total opposition to current flow in an electrical circuit. Resistance, inductance, capacitance and conductance have various influences on the impedance, depending on frequency, dielectric material around conductors, physical relationship between conductors and external factors. Impedance is often referred to with the letter Z. It is measured in ohms, whose symbol is the Greek letter omega.
   Found on http://www.zoo.co.uk/~z0001325/Glossary.
   
   
4. 
   Impedance
   1) A term for the electrical resistance found in a/c circuits. Affects the ability of a cable to transmit low level (e.g. sound) signals over a long distance. Measured in Ohms. Speakers are rated according to power handling capabilities (Watts, W) and impedance (Ohms).
   2) The total opposition offered by an electric circuit to the flow of an alternating current of a single frequency. It is a combination of resistance and reactance and is measured in ohms. Remember that a speaker's impedance changes with frequency, it is not a constant value.
   3) The opposition to alternating current.
   Found on http://www.testing1212.co.uk/a.htm
   
   
5. 
   Impedance
   Is the opposition to flow of electrical current made up of resistance (a property of the material at specified temperature), capacitance and inductance.
   Found on http://www.shponline.co.uk/glossary.asp?
   
   
6. 
   Impedance
   The complex ratio of voltage to current.
   Found on http://www.wavecor.co.uk/gloss.htm
   
   
7. 
   Impedance
   A measure of the AC (alternating current) resistance to the flow of electrical or acoustic energy. In electronics it is measured in Ohms
   Found on http://www.musiconmypc.co.uk/art_glossar
   
   
8. 
   Impedance
   At it most general electronic level, impedance is the amount of resistance and / or reactance offered by an electronic circuit or device to the (AC) current which flows through it. It is commonly represented by the mathematical symbol 'Z', and is measured in Ohms. Some people may have had an unwelcome brush with the laws of impedance when (usually ...
   Found on http://www.traditionalmusic.co.uk/music%
   
   
9. 
   Impedance
   Acoustic ImpedanceThe total reaction of a medium to the transmission of sound through it, expressed as the ratio of sound pressure to particle velocity at a given point in the medium. The acoustic impedance Z is useful in describing the acoustic radiation from sources such as surfaces and ducts.Mechanical ImpedanceMechanical impedance is the ratio ...
   Found on http://www.diracdelta.co.uk/science/sour
   
   
10. 
    Impedance
    total opposition to flow of current, measured in ohms; combined effort of resistance, inductance, and capacitance.
    Found on http://www.chemicalglossary.net/definiti
    
    
11. 
    Impedance
    Total effective resistance
    Found on http://www.electricfence-online.co.uk/is
    
    
12. 
    Impedance
    A measure of the total opposition to the flow of alternating current (A.C.) round a circuit; a complex combination of ohmic resistance and reactance.
    Found on http://www.mhs.ox.ac.uk/marconi/collecti
    
    
13. 
    Impedance
    A measure of the response of an electric circuit to an electric current. The actual value is frequency dependent. The current is opposed by the capacitance, inductance and resistance of the circuit.
    Found on http://www.mpoweruk.com/glossary.htm
    
    
14. 
    Impedance
    The total opposition to electrical flow (resistive plus reactive).
    Found on http://www.flowmeterdirectory.com/flowme
    
    
15. 
    impedance
    (electronics, physics) Opposition to flow of alternating current. Impedance consists of resistance plus reactance (capacitive or inductive). Measured in Ohms. (2003-12-02)
    Found on http://foldoc.org/
    
    
16. 
    impedance
    once the fluid is in the ground it must emerge in one or other of the boreholes with the minimum loss of flow and the minimum head loss in the system; the impedance being defined as head loss divided by return well flow Category: Electrical engineering and energy • the apparent opposition in an electrical current to the flow of an alternating current that is analogous to the actual ele...
    Found on http://www.mijnwoordenboek.nl/definition
    
    
17. 
    Impedance
    The opposition to the flow of alternating or varying current. Measured in Ohms.
    Found on http://www.revealcable.co.uk/Help/g/Glos
    
    
18. 
    Impedance
    Im·ped'ance noun [ Impede + -ance .] (Electricity) The apparent resistance in an electric circuit to the flow of an alternating current, analogous to the actual electrical resistance to a direct current, being the ratio of electromotive force to the current. It is equal to R ² + X ² , where R = ohmic resistance, X = reactance. For an i ...
    Found on http://www.encyclo.co.uk/webster/I/17
    
    
19. 
    impedance
    1. Total opposition to flow. When flow is steady, impedance is simply the resistance, e.g., the driving pressure per unit flow; when flow is changing, impedance also includes the factors that oppose changes in flow. Thus, deviations of impedance, from simple ohmic resistance because of the effects of capacitance and inductance, become more importan ...
    Found on http://www.mondofacto.com/facts/dictiona
    
    
20. 
    Impedance
    `Impedance` may refer to: *the ratio of the voltage phasor to the electric current phasor, as in **Electrical impedance, a measure of opposition to time-varying electric current in an electric circuit. **Characteristic impedance, a measure of opposition to electric current propagation in a transmission line. *Impedance matching and Impedance mismatch. *Vacuum impedance, a universal constant. *Electromagnetic impedance, a constant related to elec...
    Found on http://en.wikipedia.org/wiki/Impedance
    
    
21. 
    impedance
    (im-pēdŽәns) obstruction or opposition to passage or flow, as of an electric current or other form of energy. the resistance in alternating current circuits, represented by the letter Z in mathematical formulas. Medical equipment is often rated according to impedance to allow for optimum perform...
    Found on http://www.mercksource.com/pp/us/cns/cns
    
    
22. 
    Impedance
    • (n.) The apparent resistance in an electric circuit to the flow of an alternating current, analogous to the actual electrical resistance to a direct current, being the ratio of electromotive force to the current. It is equal to R2 + X2, where R = ohmic resistance, X = reactance. For an inductive circuit, X = 2/fL, where f = frequency and L =...
    Found on http://thinkexist.com/dictionary/meaning
    
    
23. 
    impedance
    impedance 1. Something that delays or prevents progress, or the preventing of progress. 2. Electricity opposition to flow of alternating current; the opposition in an electrical circuit to the flow of alternating current, consisting of resistance and reactance. 3. The ratio of the pressure to the volume displacement at a given surface in a sound-transmi...
    Found on http://www.wordinfo.info/words/index/inf
    
    
24. 
    Impedance
    Opposition of a circuit to an alternating current, equal to the complex ratio of the voltage to the current in complex notation. The equivalent of resistance in a DC circuit.
    Found on http://www-bdnew.fnal.gov/operations/acc
    
    
25. 
    Impedance
    A measure of the impediment to the flow of alternating current, measured in ohms at a given frequency. Larger numbers mean higher resistance to current flow.
    Found on http://www.hometheatermag.com/glossary/