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On Oct 3, 2012, at 12:20 AM, Rock <rockie5...@gmail.com> wrote: > If you are measuring Direct Current, yes. But you are measuring Alternating > Current so you have to multiply the Volt-Amps by .707 to get the actual power > developed. Volt-Amps are useful in determining circuit breaker ratings. No, you multiply Peak volts OR amps to get RMS (provided the waveform is a pure sine wave). Volts times amps is watts IF they are in phase. Purely resistive loads are in phase but complex loads, which include Switch Mode Power Supplies (SMPS) are not. For SMPSs the VA is higher than the Watt value. To understand it a little, take for example a capacitor across the AC line. The voltage and current are ninety degrees out of phase. That is, when the current is at a maximum, the voltage is zero. So no actual power is consumed, hence it draws zero watts even though it is drawing some amount of VA. In engineering terms we call this imaginary power. Watts are a measurement of real power, VA is a measurement of complex (real and imaginary) power. -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
