|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
141.239.172.61
In Reply to: RE: Full wave bridge into Choke PS posted by vetmedrobert@gmail.com on March 26, 2017 at 10:28:28
How does the value of a "small" cap which is used to adjust the voltage affect the choke input "smoothing" or hash reduction capability?
Follow Ups:
There's small and there's very small. A 0.01 muF. part is used for kickback spike protection. A part less than 1 muF. is used as a "fudge factor" to adjust the rail voltage. At some point, critical current behavior will cease and cap. I/P filtration behavior will begin. What the exact value is has to be determined on a case by case basis. I'm very suspicious of both a cap. value greater than 0.47 muF. and an attempt to significantly raise the rail voltage above the RMS value being rectified. A volt or 2 above RMS might be OK.
The bottom line is that "breadboarding" and measuring, on the bench, can't be eschewed in favor of simulations.
Eli D.
Morgan Jones in the 4th ed. of his book has a pretty comprehensive discussion of this subject.
"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln
We did empirical work years ago.VOLTAGE never moved in a choke input supply until the capacitance moved past .68 uF ...Is not lost on me .68 is a benchmark value. Interestingly, the voltage never increased more after 8 uF. Perhaps with a high or lower test VOLTAGE, these numbers might change.
The Mind has No Firewall~ U.S. Army War College.
Edits: 03/29/17
Were you measuring the setups under load? I suspect you would have noticed a droop, when that 8 μF. had to supply substantial current. Small valued cap. I/P filters are notorious for poor regulation.
Eli D.
At idle Eli, there was no signal present.
The Mind has No Firewall~ U.S. Army War College.
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: