While I was building a Ramsey Electronics FM10C I noticed that the .001 μ F capacitors were marked 102. In the parts list manual, it was stated that a .001 μ F capacitor would be marked .001 or 102 or 1nf.

There have been a few instances that I have disassembled circuits in which I cannot deduce from the markings what the capacitor values are. Is there a standard for labeling capaitors (or other components) in general? It does not seem intuitive for me that 102 would mean .001.

Thanks!
Brian

 

Originally posted by brianafischer@Apr 1 2006, 02:39 PM
While I was building a Ramsey Electronics FM10C I noticed that the .001 μ F capacitors were marked 102. In the parts list manual, it was stated that a .001 μ F capacitor would be marked .001 or 102 or 1nf.

There have been a few instances that I have disassembled circuits in which I cannot deduce from the markings what the capacitor values are. Is there a standard for labeling capaitors (or other components) in general? It does not seem intuitive for me that 102 would mean .001.

Thanks!
Brian

[post=15698]Quoted post[/post]​

Well, I just seemed to have answered my own question in a few minutes. The Ramsey Kit Building guide is a good resource for all!
Ramsey Kit Building Guide (PDF)

While capacitors also can be color-coded, Ramsey Kits use disc capacitors marked by a number-letter code.The first two digits establish the
first two numbers of the value.The third digit is the multiplier. The letter designates the manufacturing 'tolerance"or accuracy for the value
printed.
Values under 100 picofarads, used widely in our FM and VHF kits, are printed clearly with no need to interpret them further. Small capaci-
tors stamped 4.7, 10, 15, 33, 68 and so forth are 4.7, 10, 15, 33, 68 picofarads respectively! A 100 picofarad capacitor, also commonly
used in our kits, can be marked either 100 or 101! If it's marked 100, believe it. If it is marked 101, the value is 10 (first 2 digits) X 10 (3rd
digit multiplier) = 100 picofarads! If it is marked 101J, we know that it is made to 5% accuracy, while H signifies 3% and K is 10%.
Rule of thumb: If the 3rd digit is a 0, you may assume the value is in picofarads, and you can take the three numbers together as the pico-
farad value for that capacitor. So, just as in the above example, both “470” and “471” are 470 pf.

A link to some more conventions would be useful though!