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Whether power transformer 225v @70mA with 1-4ohm dcr suitable to the attached diagram?
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As Tom said, that will be a fairly terrible power supply. Model a Full wave bridge with Schottkys into a 5 henry choke with 50uf into a 3 Henry choke and 100uf. Critical choke loaded. It will be stiff and electrically silent.
You are trying to use an international harvester combine to mow your suburban yard.
What makes it terrible?
How about?
225v @70mA power transformer => Full wave bridge with Schottkys => 16H 12ohm LC choke => 50uf => 16H 12 ohm choke => 100uf => 105+v??
The problem is that "more" is not better. Once you reach a point when you have enough inductance in the power supply to achieve your filtering goals, simply increasing values does not make the power supply "more better".
You are setting up multiple resonance circuits (see formula above). With 16H and 2uf, you have a resonance frequency of 28hZ which is in the audio band.
Hey,
the ripple reduction is a function of L X C so if you double the L you can 1/2 the C and end up back where you started.
As for resonant frequency, that is simply a function of the ripple reduction required by the filter section and for any given amount of ripple reduction, the resonant frequency is constant. The only way to change the resonant frequency is to increase or decrease the filtering of a section.
While your example of a filter of 28hz being n the audio band is correct, the OP proposed 2m (which is 2000µ) of filtering which puts the resonant frequency under 1hz.
dave
"With 16H and 2uf, you have a resonance frequency of 28hZ which is in the audio band."
Look again. That's not 2uf, it's 2000uf.
PSUD2 uses "uf" for microfarad and "mf" for millifarad.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Couldn't make that out. Worse.
What about this one?
Put C1 as 0.2uf
Put C2 as 50uF
Put C3 as 100uF
You will have to change the transformer voltage to around 250 for the same output voltage.
Compare the current step response and the ripple voltage
The DCR of the chokes is so low that the filter will ring like heck unless the caps are made large.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 12/01/16
Trouble with just trying to use parts on hand.
Hello Tre'!
Can I use 600v rating for the C1 (20uf) and 200v rating cap for both C2 (600uf) as well as C3 (1800uf)??
Thanks!
Are your planning to LIFT it after you build it? Some serious iron, good for a half an amp, used at 80 mA. Filtering could be better with bigger caps, especially at the output. Which will improve damping greatly too - with existing values, it will bounce madly with load transients.
"Filtering could be better with bigger caps"
He has 4000uf in there?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Whoaaa... I'm one of those old farts that still read mF as microfarad...
Yeah, me too but PSUD2 uses uf for microfarad and mf for millifarad.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 12/02/16
I understand what you meant as I already had those 16H chokes and each weighted around 10 pounds!
All custom wound by Bartolucci for a fellow I know, and now he wants to sell all those parts as those are sitting on the shelf over 10 years! He ordered those parts for backup.
I agree those chokes are very very heavy!
Now I want to order the power transformer from different vendors, probably Monolith Magnetics.
mt
As the diagram shown, it has 2 x 6D22S as full wave rectification.
What are the advantages of using two half-wave tube rectifiers over one full-wave? More current passed?
Thanks!
-!
The Mind has No Firewall~ U.S. Army War College.
> What are the advantages of using two half-wave tube rectifiers over one full-wave? More current passed?
It is a damper diode and is only available as half wave. It has 6kV PIV, 300mA continuous current capability, low forward voltage drop, slow controlled warmup, and is inexpensive.
mt
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