West Florida Components

For those just starting out learning about electronic components (specifically capacitors and capacitance), we know that there can be some confusion related to this topic.

In short, the answer is yes — mFd is the same as uF- which is also the same as the symbol ‘µ’ as seen in ‘µF’.

Technically ‘mfd’ represents ‘milliFarad’ while ‘uF’ stands for ‘microFarad’ which is an order of magnitude smaller. Here is where the confusion begins. Some older capacitor manufacturers used ‘mF’ in place of uF on their capacitors. Whether it was because their machines could not imprint the correct symbol ‘µ’ or for another reason not known to us, this was the common practice.

Nowadays, we see about 25% of the capacitors that come into our warehouse marked as mFd but we RARELY have any that are truly milliFarads.

On our site, we refer to microfarad as ‘uF’ to keep consistent and to make it easier for customers to find the capacitors they need. In the end. there is really no right or wrong – some other sites might use mF or mFd.

If you need more information about capacitance, check out our handy capacitance conversion chart which will help you convert microfarads into picofarads and nanofarads.

We’ve been very busy expanding another category for you: Box Capacitors.  Now in stock and ready to ship are more than 60 different values of box capacitors. In general, box caps are constructed of polyester film or metallized polypropylene. Some of the more popular manufacturers are Wima, Mallory and Philips.

In addition, (and somewhat related), we’ve greatly expanded our suppression and safety capacitor category. Between both categories, there are almost 75 new products added this week alone! Look for quantity discount pricing on almost all of the capacitors.

And, as always, we do not require a minimum purchase and our first class mail shipping rates are still a very reasonable $3.50 for all US purchases up to $15.00.

We are often asked about the difference between the two different types of motor capacitors: motor run and motor start. Here are the basic differences between the two:

Motor Start Capacitors
The primary purpose of a motor start capacitor is to briefly increase the motor starting torque as well as to allow a motor to be cycled on and off very quickly. It operates in the circuit by staying active long enough to allow the motor to be brought to 3/4 of it’s full capacity. It is removed at that point by a switch in the circuit. You will find that the voltage rating is often one of these four: 125VAC, 165VAC, 250VAC, and 330VAC.

Motor Run Capacitors
Motor run capacitors will then operate after the circuit is started. Using a motor run capacitor will run the motor with greater efficiency. Motor run capacitors are designed for continuous duty. They are energized while the motor is in operation. You will often find motor run capacitors with a voltage rating of 370VAC or 440VAC with a capacitance of 1.5uF – 100uF. Typically, the construction material is polypropylene film.

Operational information
Electric motors that are single phase require a capacitor for a second-phase winding. If you use the wrong motor run capacitor, the rotor may hesitate due to an uneven magnetic field. The hesitation may result in performance issues such as a noisy or overheated motor, increased energy consumption and general decreased performance.

Faulty motor capacitors
You can sometimes spot a faulty motor run capacitor by it’s swollen appearance – or it may have blown and become leaky. Of course, these capacitors should be carefully replaced. In addition to an outright capacitor failure, the capacitance may become reduced over time. Capacitors that are operating with a decreased capacitance may create performance issues. Again, these capacitors should be carefully replaced.

Opening up and tearing down an IPOD Shuffle to see what’s inside…

The 3rd Generation of the IPOD Shuffle is a wonder of technology….1000 songs stored in an aluminum case smaller than a disposable lighter.

Did you ever wonder what electronic components make up the guts of an IPOD Shuffle?

You might be surprised at what goes into the circuitry of the IPOD Shuffle. In descending order by percentage of cost, the main components are:

logic, memory, metals, rechargeable materials, connectors, PCB, crystal, misc, capacitors, transistors, analog, diodes, magnetic, and plastics.

Here’s a partial breakdown by number of electronic components:

Capacitors – 65+
Resistors – 50+
Diodes – 4+

Pretty amazing what goes into equipment that measures only 45.2mm x 17.5mm x 7.8mm when fully assembled! This is possible because the components are extremely small surface mount components.

If you look at the cost breakdown by component family, it’s just as revealing. Naturally, the largest share is for memory in the form of IC’s. Over 70% (about $12.00 worth) is for logic and memory.

Capacitance Values – and How to Read Them

Capacitors are used in a wide range of electronic components and circuits. They form an integral part of electronics. The capacitance of capacitors is measured in a unit known as Farads, represented by the letter ‘F’. A capacitor that has higher capacitance can be used for storing more charge as compared to one with a smaller capacitance value.

One Farad is a very high value for capacitance and usually smaller units are used, namely pico farad, nano farad etc. And as the capacitors are physically very small in size, their capacitance needs to be identified with a code mentioned on the capacitor itself. The exception to this is electrolytic capacitors that are big enough to have the capacitance value written directly on them.

Ceramic and film capacitors usually have a coded value marked on them. If the value marked on them is a two-digit whole number, then the capacitance is equal to the value mentioned in pico Farads. Thus a code of “10” implies that the capacitance is equal to 10 pico farads.

A three-digit whole number includes the first two significant digits, and the third digit as the multiplier (indicating the number of zeroes), and gives the value in pico Farads. Thus a code of “104” means, 10 multiplied by 10,000, giving the capacitance as 100,000 pF or 0.1 uF.

If a decimal number is used as the code on the capacitor, then the capacitance is equal to value mentioned in micro Farads. For instance, “.1” mentioned on the capacitor would imply 0.1 uF.

Finally, a whole number followed by the alphabet ‘n’ means the capacitance is equal to value mentioned in nano Farads.

In addition to the capacitance, the code on these electronic components can also be used for indicating the tolerance, voltage, and temperature properties.

In the example above, the capacitor reads:

471M

3KV

The 471 is deciphered as 470pF; M=20% tolerance; 3KV=3,000V

Here are the codes for tolerance:

B	+/- 0.1pF
C	+/- 0.25pF
D	+/- 0.5pF
E	+/- 0.5%
F	+/- 1%
G	+/- 2%
H	+/- 3%
J	+/- 5%
K	+/- 10%
M	+/- 20%
N	+/- 0.05%
P	+100% ,-0%
Z	+80%, -20%