Author Topic: I hate capacitor markings  (Read 2864 times)

0 Members and 2 Guests are viewing this topic.

Offline snowmix

  • Contributor
  • Posts: 9
I hate capacitor markings
« on: August 12, 2015, 12:50:57 am »
So I put together a breadboard arduino and it wouldn't work. I tried to use two of these capacitors I found at a yard sale marked 220 for the crystal.i

When i tested the capacitors the read .202nf and I the a 22pf should read .022nf. Are these just miss marked or something.
 

Offline T3sl4co1l

  • Super Contributor
  • ***
  • Posts: 14550
  • Country: us
  • Expert, Analog Electronics, PCB Layout, EMC
    • Seven Transistor Labs
Re: I hate capacitor markings
« Reply #1 on: August 12, 2015, 12:57:56 am »
Usually 220pF should be marked "221" and 22 as "220", but they often leave off the multiplier if it's two digits or less.  Which makes "220" versus "221" ambiguous.

Unless you specifically purchased the part from a known good supplier, and have the envelope or baggie with the exact manufacturer's part number on there, and have looked up that number to verify the value... yeah, you're pretty much better off measuring it.

So your measurement is correct, 220pF it is.

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 

Offline snowmix

  • Contributor
  • Posts: 9
Re: I hate capacitor markings
« Reply #2 on: August 12, 2015, 01:03:28 am »
I have some 10pf caps can I use two of them to get to 20pf?
 

Offline retrolefty

  • Super Contributor
  • ***
  • Posts: 1614
  • Country: us
  • measurement changes behavior
Re: I hate capacitor markings
« Reply #3 on: August 12, 2015, 01:20:08 am »
I have some 10pf caps can I use two of them to get to 20pf?

 Yes if wired in parallel. However I would just try using two 10pf caps for the crystal padding. It's only likely to change the crystals frequency by a few 100 Hz, not enough to effect anything. Note the the current Arduino Uno uses a ceramic resonator rather then a crystal, so high frequency accuracy isn't an arduino thing.  ;)

 

Offline snowmix

  • Contributor
  • Posts: 9
Re: I hate capacitor markings
« Reply #4 on: August 12, 2015, 01:23:00 am »
Thank you guys I got it working.

Sent from my Studio Mini LTE using Tapatalk

 

Offline flynwill

  • Regular Contributor
  • *
  • Posts: 141
Re: I hate capacitor markings
« Reply #5 on: August 12, 2015, 03:56:22 am »
Now I know I'm getting old. When I looked at your picture I immediately though "220 pF".  Back in the day that it the way these disks were always marked.  22 pf would be marked "22".
 
 

Offline TheElectricChicken

  • Frequent Contributor
  • **
  • Posts: 480
  • Country: au
Re: I hate capacitor markings
« Reply #6 on: August 12, 2015, 06:35:32 am »
Thank goodness for multimeters as you get older and can't see so well. Resistor codes used to be easy to read, now the colours look all the same. I think you won't come across so many caps poorly marked as resistors hard to read. But at least we can outsmart them with meters. 3 cheers for the multimeter ! 8-)
 

Offline Deathwish

  • Supporter
  • ****
  • Posts: 1426
  • Country: wales
Re: I hate capacitor markings
« Reply #7 on: August 12, 2015, 06:41:56 am »
all caps should be coloured like mullard ones.
Electrons are typically male, always looking for any hole to get into.
trying to strangle someone who talks out of their rectal cavity will fail, they can still breath.
God hates North Wales, he has put my home address on the blacklist of all couriers with instructions to divert all parcels.
 

Offline philpem

  • Frequent Contributor
  • **
  • Posts: 295
  • Country: gb
  • That Sneaky British Bloke
Re: I hate capacitor markings
« Reply #8 on: August 12, 2015, 07:02:06 am »
all caps should be coloured like mullard ones.
They certainly looked prettier  ;D
Phil / M0OFX -- Electronics/Software Engineer
"Why do I have a room full of test gear? Why, it saves on the heating bill!"
 

Offline ResR

  • Regular Contributor
  • *
  • Posts: 149
  • Country: ee
  • -Artificial_Intelligent-
Re: I hate capacitor markings
« Reply #9 on: August 12, 2015, 07:21:00 am »
The tropical fish capacitors are quite nice indeed.
...Resistor codes used to be easy to read, now the colours look all the same...
I have 1990's resistors from old european origin tv where brown, red and orange all look the same on dark red background and brand new resistors with 4 bands that has the colors clear as day. It really depends on factory that makes these rather than age. Cheers for the multimeter from me too.  :-DMM
 

Offline Psi

  • Super Contributor
  • ***
  • Posts: 7439
  • Country: nz
Re: I hate capacitor markings
« Reply #10 on: August 12, 2015, 08:48:04 am »
i hate that tantalums break the convention and have a small line for positive.
« Last Edit: August 12, 2015, 09:15:38 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline Zero999

  • Super Contributor
  • ***
  • Posts: 13425
  • Country: gb
  • 0999
Re: I hate capacitor markings
« Reply #11 on: August 12, 2015, 08:55:43 am »
i have that tantalums break the convention and have a small line for positive.
All the tantalum capacitors I've seen have a line for the positive. I don't know why tantalum capacitors mark the positive and aluminium capacitors mark the negative. It's very retarded.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf