# Power in flyback converter

H

#### Hammy

Jan 1, 1970
0
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. D #### D from BC Jan 1, 1970 0 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.

There's the crazy calorimetic method.
Example:
http://honolulu.hawaii.edu/distance/sci122/Programs/p21/image.gif

I do efficiency estimates in spice.
Core loss by software.

D from BC
British Columbia

H

#### Hammy

Jan 1, 1970
0

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?
I do efficiency estimates in spice.
Core loss by software.

D from BC
British Columbia

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.

Thanks

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