An excellent photo showing good, and poor, solder joints.

# Category: Ham Radio

## Capacitors – Now we add letters to the mix

Adding letters to capacitor values isn't that complicated; it's just one more little detail to be aware of. The following sums up some basic letter codes for capacitor tolerances:

Some capacitors are defined by a three number code followed by a letter. This letter represents the tolerance of the capacitor, meaning how close the actual value of the capacitor can be expected to be to the indicated value of the capacitor. The tolerances are indicated as follows:

Read B as 0.10 percent.

Read C as 0.25 percent.

Read D as 0.5 percent.

Read E as 0.5 percent. This is a duplication of a D code.

Read F as 1 percent.

Read G as 2 percent.

Read H as 3 percent.

Read J as 5 percent.

Read K as 10 percent.

Read M as 20 percent.

Read N as 0.05 percent.

Read P as plus 100 percent to minus 0 percent.

Read Z as plus 80 percent to minus 20 percent.

The above was copied from this site, which adds a little bit more info.

Next week, we'll talk about more naming schemes, and wind up with a couple of links which illustrate just how (unnessarily?) complex this subject can become.

## One of the many capacitor numbering schemes

This is a tiny ceramic capacitor. You can only read the stuff printed on it under high magnification

Let's say that this is the same capacitor, but under high magnification. But what does '104' mean? Is it some kind of model number? Inventory number? Does it mean nothing to anyone but space aliens?

Nope. It tells you it's capacitance, in picofrads. The first two digits indicate part of it's capacitance value. The third digit indicates the number of zeros which follow the first two digits.

Thus, it's capacitance is 10, followed by four zeros, i.e., 100,000 picofarads (100,000 pF)

You can also just drop the last three zeros and call it 100 nanofarads (100 nF). Both are the same value; they're just written differently.

You can find out a bit more here.

And even more, in a straight-to-the-point video, here.

## That strange stuff printed on capacitors

This begins a series of posts about stuff which is printed on the outside of capacitors. We'll deal with some of the schemes for indicating mF, uF, nf, and pF.

For our purposes:

1 mF is also known as

one one-thousandth of a Farad

10 to the minus-3rd power of a Farad

0.001 of a Farad

1 millifarad

1 uF is also known as

one one-millionth of a Farad

10 to the minus-6th power of a Farad

0.000001 of a Farad

1 microfarad

1 nF is also known as

one one-billionth of a Farad

10 to the minus-9th power of a Farad

0.000000001 of a Farad

1 nanofarad

1 pF is also known as

one one-trillionth of a Farad

10 to the minus-12th power of a Farad

0.000000000001 of a Farad

1 picofarad

There are much larger capacitor values in other branches of electronics but we don't need to deal with that on a ham radio site.

Next, we begin relating the above definitions to the many codes used by capacitor manufacturers.

Meanwhile, there's more material about similar math notation on Wikipedia.

Appropos of nothing: there are also the mathematical prefixes Zepto- and Yocto-, which are not needed here. They just sound like two long lost Marx brothers. You know, Groucho, Chico, Harpo, Zeppo, Gummo, Zepto, and Yocto.

## CW/QRP Club

## HamSpeak

Mostly oriented toward, or originating from, Morse Code:

http://www.hamuniverse.com/qsignals.html

## She’s off to a Good Start!

Nine years old...and has already had her first satellite QSO. According to the FCC database, she earned her first Ham license in March of 2015 (at age 8?), and currently holds a General class ticket.

Look out, world!

## Field Day

Enter the hashtag

#AARLFD

on Facebook or Twitter. On Twitter, you don't have to join, just enter it into the search field.

Comments? Similar hashtags? Just click on 'Write a comment', above.

## Dayton Hamvention

Time to start thinking about http://www.hamvention.org

Have you attended in the past? What was it like? Comments welcomed; just click on 'Write a comment', above

## Gender Imbalance in Ham Radio

Here's a discussion on gender imbalance in ham radio, written by Dr. Yvette Cendes, KB3HTS, an Astrophysicist.

http://qrznow.com/gender-imbalance-in-ham-radio/

Comments? Similar links? Just click on ‘Write a comment', above.