Lessons In Electric Circuits Volume II – AC Book

Chapter 3.7 Contributors

Lessons In Electric Circuits Volume II – AC Book
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Lessons In Electric Circuits Volume II – AC Book

  • 76CHAPTER 3. REACTANCE AND IMPEDANCE – INDUCTIVERAC = (RDC)(k)fWhere,RAC =RDC =k =f =AC resistance at given frequency "f"Resistance at zero frequency (DC)Wire gage factor (see table below)Frequency of AC in MHz (MegaHertz)Table 85,3.2 gives approximate values of “k” factor for various round wire sizes.Table 3.2: “k” factor for various AWG wire sizes.gage sizek factorgage sizek factor4/0124.5834.82/099.01027.61/088.01417.6269.81810.9455.5226.86647.9--For example, a length of number 10-gauge wire with a DC end-to-end resistance of 25 Ω wouldhave an AC (effective) resistance of 2.182 kΩ at a frequency of 10 MHz:RAC = (RDC)(k)fRAC = (25 Ω)(27.6)10RAC = 2.182 kΩPlease remember that this figure is not impedance, and it does not consider any reactive effects,inductive or capacitive. This is simply an estimated figure of pure resistance for the conductor (thatopposition to the AC flow of electrons which does dissipate power in the form of heat), corrected forthe skin effect. Reactance, and the combined effects of reactance and resistance (impedance), areentirely different matters.3.7ContributorsContributors to this chapter are listed in chronological order of their contributions, from most recentto first. See Appendix 2 (Contributor List) for dates and contact information.Jim Palmer (June 2001): Identified and offered correction for typographical error in complexnumber calculation.