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Projects => How Do I? Beginner's Paradise. => Topic started by: Bret608 on September 21, 2012, 06:33:25 AM

Title: Identifying box caps by the little numbers on top
Post by: Bret608 on September 21, 2012, 06:33:25 AM
Hi everyone,

How do you read the numbers on top of our old friend the box capacitor? I've got five of them going onto a Wolfshirt board this afternoon, and want to make sure I've got it right. So I've got a specific task here, but since I'll surely use this knowledge many times after, I thought this would be the right place for the thread.

So for example, here are the numbers on the caps and what I think they mean after looking at the BOM:

104J100: 100n?
102J100: 1n?
473J100: 47n? (subbing for the 50n cap)
332J100: 3n?

Thanks in advance for the help as always!

Bret
Title: Re: Identifying box caps by the little numbers on top
Post by: culturejam on September 21, 2012, 06:58:38 AM
You have it right on the values.

It breaks down like this:

Value | Tolerance | Voltage Rating

104J100


104 = 100n  (10 + 4 zeroes, in picofarads)

J = 5% tolerance

100 = 100v rating


For more reading:
http://www.electronics2000.co.uk/data/itemsaf/capmarks.php
Title: Re: Identifying box caps by the little numbers on top
Post by: Bret608 on September 21, 2012, 07:04:03 AM
I appreciate it! This site looks to be a great resource.
Title: Re: Identifying box caps by the little numbers on top
Post by: Guitafuzz on September 21, 2012, 08:21:16 AM


   Hi Bret this table can be useful too together with the explanion of culturejam.

   
Title: Re: Identifying box caps by the little numbers on top
Post by: DutchMF on September 21, 2012, 12:34:39 PM
Quote from: culturejam on September 21, 2012, 06:58:38 AM
You have it right on the values.

It breaks down like this:

Value | Tolerance | Voltage Rating

104J100


104 = 100n  (10 + 4 zeroes, in picofarads)

J = 5% tolerance

100 = 100v rating


For more reading:
http://www.electronics2000.co.uk/data/itemsaf/capmarks.php

Good stuff CJ, thanx! I knew a lot of this in bits and pieces, but seeing it like this in one concise post is always a pleasure!

Paul
Title: Re: Identifying box caps by the little numbers on top
Post by: culturejam on September 22, 2012, 10:31:26 PM
Here's another handy chart for converting between the various multipliers of values:
http://www.justradios.com/uFnFpF.html