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Electronics => Electronics => Topic started by: ksquared on September 13, 2009, 09:37:23 PM

Title: Reading Capactiors
Post by: ksquared on September 13, 2009, 09:37:23 PM

Let us say I have this bag of assorted capacitors, from radioshack.  Alas, the only markings on them are some numbers, underlines, and a mark of some kind at the apex of the capacitor body, but I would like a specific value.  How might someone read these things?

Title: Re: Reading Capactiors
Post by: SmAsH on September 14, 2009, 01:11:10 AM

Capacitance is measured in uF, nF and pF.
Do you know what kind of capacitor you are using? ceramic, electrolytic?
What are some of the numbers on the capacitors, normally they just have voltage and capacitance...

Title: Re: Reading Capactiors
Post by: ksquared on September 14, 2009, 07:25:59 AM

They are are ceramic.  The numbers include things like 10, 271.  One I have lying around just stays 102, and has no other markings on it whatsoever.  

I have cleverly thus misplaced them.  I will be getting more descriptive shortly or this evening, schedule permiting.  Thank you for the interest so far.

Title: Re: Reading Capactiors
Post by: chelmi on September 14, 2009, 09:36:52 AM

Quote from: ksquared on September 14, 2009, 07:25:59 AM

They are are ceramic.  The numbers include things like 10, 271.  One I have lying around just stays 102, and has no other markings on it whatsoever.  

I have cleverly thus misplaced them.  I will be getting more descriptive shortly or this evening, schedule permiting.  Thank you for the interest so far.

http://www.electronics2000.co.uk/calc/capacitor-code-calculator.php (http://www.electronics2000.co.uk/calc/capacitor-code-calculator.php)

Title: Re: Reading Capactiors
Post by: ksquared on September 14, 2009, 07:41:50 PM

Thanks!  That let me find the ones I needed.  What about the ones with only two (or one) digits in the code?

Title: Re: Reading Capactiors
Post by: galannthegreat on September 14, 2009, 08:10:21 PM

All ceramic caps are measured in pF... and if you know your metric prefixes you'd know that pico= x10^-9   (times ten to the negative nine... engineering notation helps here). It really helps to learn this code, myself, as a future electronics technician I have no excuse to not have this down, but for yourself I'd recommend studying this code, along with the resistor code, it will make your life sooooooo much easier, trust me.

Title: Re: Reading Capactiors
Post by: Soeren on September 20, 2009, 06:19:27 AM

Hi,

Quote from: galannthegreat on September 14, 2009, 08:10:21 PM

All ceramic caps are measured in pF...[...] trust me.

Except those measured in nF... Don't just trust me, see for yourself:  ;D
(http://quality-deal.com/osCommerce/images/CAP-005D.bmp)
(470pF marked as n47, meaning 0.47nF)
Most, if not all, of the ceramic caps of the matte yellow and grey varieties are marked in nF.

Title: Re: Reading Capactiors
Post by: galannthegreat on September 20, 2009, 09:55:46 PM

Well I'm going based on the capacitor code, not by the caps that will state their capcitance right on them, things like 102, 103... are all measured in picos.