[Boatanchors] Re: Caps

[Richard Keller]

Stephen,
Yup. I know all that. Have been in electronics for 50 years.
I was just curious what others have done when the original
values are no longer available, and the newer standard
values do not work mathematically for a given older value.
The series and parallel arrangement is quite clear and I
know you cannot use a lower voltage cap. In the case of the
450's I need, going higher in voltage is not an option
without a much higher price. You just cannot practically
come up with 80 uf using available values. A concern also
was voltage ratings since the newer ones with  higher
voltage ratings can be used to sub for lower voltage
original caps, not as it was back when they had to be either
the same voltage or slightly higher.(thanks to modern
technology)

I guess I have my answer now. I will use 150 uf for the
125's. Using the lower voltage/lower capacitance in parallel
is not how I want to do it since it takes up too much room.

To all who replied, thanks so very much for all the tips. As
usual, there are many ways to do things and all work under
the right circumstances. ALL SUGGESTIONS ARE ALWAYS WELCOME!

73, Dick KF4NS
St. Petersburg, FL 33714 USA
Keep the glow!

----- Original Message -----
From: <StephenTetorka at cs.com>
To: <rkeller at ij.net>
Sent: Friday, September 24, 2004 9:23 AM
Subject: Caps


| Hello Dick:
|
| For typical power supply filtering, you have a lot of
leeway on capacitance...as long as you replace with HIGHER
VALUE.
|
| Higher capacitance improves the smoothening of the
ripple...and I would suggest you read on the subject to
become acquainted with the matter.
|
| Replacing a 20 pf with 100 pf should not be a problem.
|
| Remember that placing two capacitor in parallel ADD
capacitance...so you can buy less costly smaller cap values
and solder them together.
|
| VOLTAGES ALWAYS ALWAYS NEED TO BE EQUAL OR GREATER in
direct single unit replacement.
| Voltages can be smaller when two capacitors are used in
SERIES.
| Read up on this too.
|
| Power supplies use electrolytic capacitors - do you how
these are different from others?
|
| Electrolytics must be replace with Electrolytics.
|
| Regards,
| Steve
| WA2TAK