Quasimodo results (ONLY)

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#22
Mark, Michi124,


thanks for verification!


I already did the calculations with the same results. As it it these first time I use this experimental approach I was unsure of the value for Rs I got.


Regards,
Michael



Mark Johnson said:
Audiomusica, since you doubt your experimental results from No-Math Quasimodo, you have no other choice than to use math for verification.

Your numerical values of fosc (6.25E+5) and Cx (1.0E-8) indicate that the secondary self inductance L is about (6.5E-6) Henrys. We calculate L using the LC resonance equation.
The LC resonance equation: 2 * Pi * fosc = 1 / sqrt(L * C)​
Plugging this value for L into equation (A.11) of the Quasimodo design note, we find
R < 12.7 ohms​
Which seems to be in broad agreement with your experimental results. You were wrong to doubt them.
Click to expand...
 
#23
Mark, this is my result for AMGIS L01-6364, 2x115V / 2x18v / 25VA, and i am confuse because Cs is 3 time Cx and no 15 time like your recommendation,
CX: 0,22uF
CS: 0,68uF
RS: 11 Ohm
fosc ~ 60kHz
I have a very hard time to check and use the Math for verification, by any chance do you have an Excel were we can enter the values we found ( Cx, Cs, Fosc) with the result of RS....for Zeta=1


Just got the PCB today See post Quasimodo 4
 
#26
Vigortronix VTX-146-050-218 50VA 115/230 18+18
Primaries in series (230V)
Cx 10nF
Cs 150nF
Rs 26Ω / 26Ω


Vigortronix VTX-146-050-212 50VA 115/230 12+12
Primaries in series (230V)
Cx 10nF
Cs 150nF
Rs 19.8Ω / 19.5Ω


Jaycar MT2086 20VA 240V 15+15
Cx 10nF
Cs 150nF
Rs 20Ω / 20Ω
 
#28
Oops ...
After all this time, finally remembered to post my results over here.
😱
Using Hammond 229D40 transformers acquired from Mouser
"My" chosen snubber values are:
0.15uF, 0.01uF and 424ohms (I have a BUNCH of 196 ohm and 226 ohm resistors so easily made my "424"ohm resistor, but that much accuracy is not needed 🙂 )

mlloyd1
 
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#34
Talema 70053K 15VA 2x15V
Cx 10nF
Cs 150nF
Rs 30Ω
 

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#38
AnTek AS-3218

AnTek AS-3218 115v-18v



.01uF
.15uF


Primary shorted



1st secondary other shorted

10-12ohms


2nd secondary other shorted
10-12ohm


Both look pretty good, but I wrote 10R on the box for when I use it.
 

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