churchhaze
Well-Known Member
For a power supply that claims 0.99 power factor (on 115VAC) you can assume the phase lag/lead between wall voltage and current into the driver is negligible and can basically just multiple the AC voltage and current treating the the driver/cob combo in total as a resistive load.DC power is calculated as volts times amps and can be easily measured with two multimeters. A high-resolution multimeter measures the current delivered to the load and a standard multimeter measures the power supply’s output voltage.
AC input power can’t be calculated simply as RMS input voltage times RMS input current because of the differences in phasing between the voltage and the current in an AC system, designated as ϕ and seen in figure 1. If we did this, it would yield a result that’s too high because the value would include both the power converted by the power supply (P) and the power that’s returned to the AC source (Q). (...)
Or am I wrong about this? (that's always what I assumed)
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