The following may be of some help-
     In IPC-T-50F, "Terms and Definitions for Interconnecting and 
     Packaging Electronic Circuits"
     
     Impedance- "The resistance to flow of current, represented by an 
     electrical network of combined resistance, capacitance and inductance 
     reaction, in a conductor as seen by an AC source of varying time 
     voltage. The umit of measure is ohms."
     In C.A. Harper's and M. B. Miller's "Electronic Packaging, 
     Microelectronics, and Interconnection Dictionary", McGraw Hill 
     (1993), lib. call no. TK7804.H34 1993.
     
     "Impedance- the total opposition that a circuit offers to the flow of 
     alternating current or any other varying current at a particular 
     frequency. It is a combination of resistance R and reactance X, 
     measured in ohms and designated by Z
                Z = sqrt(R^2 + X^2) "{square root of the sum of the 
     squares}
     
     See also "Cnrolled-impedance Cable" and "Impedance Match" definitions in 
     Harper and Miller.
     
     
     
     
______________________________ Forward Header __________________________________
Subject: Controlled Impedance
Author:  [log in to unmask] at _internet 
Date:    7/7/95 12:31 PM
     
     
Does anyone out there have a simple, non-technical definition 
of controlled impedance? We are having some difficulty 
explaining satisfactorily to some management types.
     
Thanks,
Bob Smith 
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