I'm trying to take efficiency measurements on a 10.5W Flyback with what I have available (DSO and DMM). The best method I can think of is uploaded to "alt.binaries.schematics.electronic " in pdf format.
File name Flyback.pdf (60Kb)
I also compared my measurements with the $20 killAwatt meter. For a twenty dollar meter it's not too bad. This of course assumes my measurements and calculations are correct. I'm sure someone will point out any errors ;)
The measurements were done with the flyback delivering 5.72W into a resistive load. Largest power resistors available until tomorrow.
Yes I've heard of it Ridley and Dixon reference it in there publications. I'm under crippling economic constraints though what with the price of water, wood, and air and not to mention complexity; the method is out of reach;) What do you do stick one finger on the DCbus and one finger in the water and get the coroner to measure the splatter pattern of your heart?:)
Yes spice can give reasonably accurate results if you take the time to model all components and trace parasitics factor in tolerances temperature dependences etc. but I still prefer to actually measure. I wouldn't rely on it solely, any analytical method spice are manual calculation gives theoretical results which should be tested and verified by measurement under worst case conditions. Failure to do so can result in some embarrassing and expensive situations .Exploding laptops comes to mind.
Those measurements seem accurate enough when compared to spice and manual calculations and the killawatt. Not so critical for this 10.5W but for the 70W flyback and 200W forward converter I should be able to use it for reasonably accurate results. Or at least good enough I can be sure my fuse, cap, bridge, CM choke and SMPS core are properly sized.
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