250 uufd?

mc1822d

Dec 27, 2019
6
Joined
Dec 27, 2019
Messages
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I want to re-cap an old shortwave receiver but I cannot find a 250 uufd mica capacitor. As a matter of fact I can't even find any capacitor with a uufd designation.. Is there a cross-reference for this value? This value is listed in the construction manual list of parts from an old Lafayette tube shortwave receiver.

 

HarryA1

Mar 4, 2009
481
Joined
Mar 4, 2009
Messages
481
Capacitor conversion chart / table
- a capacitor value conversion chart or capacitor conversion table to convert
capacitor values between
picofarads (pF),
nanofarads (nF),
microfarads (µF)

Capacitor Conversion Chart
microfarads (µF)     Nanofarads (nF)     Picofarads (pF)
0.000001                       0.001              1
0.00001                         0.01                10
0.0001                           0.1                  100
0.001                            1                     1000
0.01                            10                  10000

240 pf capacitors are available on ebay


 
 

mc1822d

Dec 27, 2019
6
Joined
Dec 27, 2019
Messages
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I realize that uf means microfarads but what are uuf capacitors? Is that an old designation for microfarads?

 
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HarryA1

Mar 4, 2009
481
Joined
Mar 4, 2009
Messages
481
"Micromicrofarad" or "micro-microfarad" is an obsolete unit found in some older texts and labels, contains a nonstandard metric double prefix. It is exactly equivalent to a picofarad (pF). It is abbreviated μμF, uuF, or (confusingly) "mmf", "MMF", or "MMFD".

A microfarad is 10 to the -6 so a micromicrofarad is 10 to the -12  =  picofarad

from: https://en.wikipedia.org/wiki/Farad

Good luck with your radio. I  repaired lots of radios years ago. I wish I had some of the old radios I cut up for parts. I still like tubes!

 
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