1
\$\begingroup\$

This question already has an answer here:

I'm sorry if this has been asked, as it's a simple question, but I haven't found it.

Is there any reason why capacitors are built in so fixed values? For any other components the manufactured value are round numbers, for example resistors 100 Ohm - 1 kOhm - 10 kOhm - ... but capacitors come in weirder numbers, specifically, why can you find multiples of 4.7? is there anything special about that number? is there any normal circuit that goes on everything that needs a capacitance like that?

\$\endgroup\$

marked as duplicate by Passerby, placeholder, Nick Alexeev, Dave Tweed, Anindo Ghosh May 5 '13 at 5:30

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

4
\$\begingroup\$

Look at a supplier catalogue for your resistors. They too are available in sizes of 2.7, 3.3, 6.8, 8.2 just like their capacitor cousins. Inductors follow this pattern as well.

The sizes of components progress through the a series from 1-10 in a way that the neighbor values are within step sizes of 5%, 10% or 20%. You can read a nice write up in the concept of preferred values here. Look specifically for the E-series as it relates to electronics.

\$\endgroup\$

Not the answer you're looking for? Browse other questions tagged or ask your own question.