As with resistors and inductors, standard capacitor values have emerged. Capacitors come in various package forms, voltage and current handling capacity, dielectric types, quality factors, and a variety of other features.
Nonetheless, a capacitor mostly hold themselves to work following this set of ideals. A capacitor is among the four basic types of passive electronic components; the inductor, resistor, and memristor are the others. The Farad is the fundamental unit of capacitance (F). It is important to use parallel and series combinations to gain alternative capacitance values.
Complex combinations are frequently used to meet several requirements, such as tolerating high voltages while maintaining the proper capacitance. If you need to tune a circuit regularly, you’ll need a variable capacitor. For example, a manually adjusted capacitor or an electrically tuned capacitor, such as a varactor diode, can be used (varicap).
These are good methods for detecting pin pitch, breadth, and size variations between your footprint and the actual part.
Knowing which capacitor you need can be tricky. However, we created an easy reference SMD Footprint Chart; if you are running into problems, these charts can save you hours. A good example being the 0805 capacitor dimensions are double the 0402 capacitor dimensions.
By the end of our guide, you’ll have enough information of which capacitor are commonly used in the same task as you are undertaking. (Read Danco O-Ring Sizes Chart)
What Are The Sizes Of Capacitors?
Capacitors are a popular type of electrical component, and their values are commonly
expressed in microfarads (F), nanofarads (nF), or picofarads (pF).
There is a lot of crossover between these multipliers. For example, 0.1F can be expressed as 100nF, and there are many other examples of this type of ambiguity in notation.
The nano farad, nF, is also less common in other fields, with values stated in fractions of an F and huge multiples of picofarads, pF. Therefore, when components indicated in nanofarad are accessible, it may be essential to convert to nanofarads, nF, under certain instances.
Circuit diagrams and electronic components lists can be confusing when they say a value in picofarads, but listings for an electronic component distributor or a store that sells electronic components say the same thing in a different way.
It’s also essential to ensure that the electrical component values are provided in the current multiple of ten while doing electronic circuit design. Being off by a factor of 10 may be disastrous!
Conversion of capacitance Surface mount capacitors, ceramic capacitors, electrolytic capacitors, tantalum capacitors, and other types of capacitors are all referred to as uf, nf, and pf.
In an easy-to-read tabular style, the capacitor conversion chart below shows the equivalents between F, nF, and pF.
When purchasing electronic components from an electronic components distributor or retailer, the marks of specifications may use different notations, requiring conversion.
Capacitor values can range around 109 or higher, thanks to introducing supercapacitors.
The standard prefixes pico (10-12), nano (10-9), and micro (10-6) are often used to avoid misunderstanding with high numbers of zeros connected to the values of different capacitors.
When converting between capacitor values, a capacitor conversion chart or capacitor conversion table can come in handy.
Also, some capacitors are marked with picofarads instead of nanofarads or microfarads, so the capacitance value has to be converted to nanofarads or microfaradas.
Electrolytic, tantalum and ceramic capacitors are among the leaded and SMYT capacitors available.
Multipliers are also used in various types of electronic components. For example, inductors are measured in Henries, and their values are much smaller.
Resistors are measured in higher multiples such as k or &M, whereas inductors are measured in Henries, and their values are much smaller.
As a result, milli- and micro-Henries are commonly employed, and equivalent conversions may be required. (Read Allen Wrench Sizes)
These are the most commonly available capacitor values, yet tolerances depend on the dielectric form and package type.
How Do I Calculate What Size Capacitor I Need?
One of the main places you’ll find a capacitor is on air conditioning units, so that is what will be used in this example.
You’ll need to measure the total voltages between the HERM and COMMON terminals on the run capacitor while the condensing unit is under load (i.e., 345 VAC).
Then, on the Compressor, measure the amperage on the wire flowing from HERM to START (i.e., 4 amps).
To check the capacitor’s size, use the calculation below. The resulting microfarads numbers (uf) should be the same as your capacitor size.
The motor’s magnetic field will be unbalanced if the capacitor is too large or too small.
This reluctance during operation will result in noisy operation, increased power consumption, decreased motor performance, and finally overheating or overloading of motors such as compressors.
The run capacitor should be the same microfarad (uf) as the motor.
Capacitors rated at 70uf or more are known as Start Capacitors and are usually
disconnected from the circuit electrically during operation.
For Start Capacitors (ONLY), this is where the rule of +/- 10% of the rating comes from.
The voltage rating should be as high as the motor’s quoted value, normally 370VAC for central heat pumps and air conditioners.
Most new condensing systems use 440VAC capacitors, which are more resilient during power supply changes.
You can find some universal type of dual run capacitors rated for up to 700VAC, which does not affect their performance.
Changes in uf will affect amperage draw and, as a result, kilowatt-hour usage.
With air conditioners, it’s a good idea to check capacitors and verify the capacitor size as part of any early season maintenance. (Read Spark Plug Socket Size)
|SMD Capacitor sizes in Inches|
|EIA CODE||SMD Capacitor Size|
|1005 footprint||0.0157 in × 0.0079 in|
|0201 footprint||0.024 in × 0.012 in|
|0402 footprint||0.039 in × 0.020 in|
|0603 footprint||0.063 in × 0.031 in|
|0805 footprint||0.079 in × 0.049 in|
|1008 footprint||0.098 in × 0.079 in|
|1206 footprint||0.126 in × 0.063 in|
|1210 footprint||0.126 in × 0.098 in|
|1806 footprint||0.177 in × 0.063 in|
|1812 footprint||0.18 in × 0.13 in|
|1825 footprint||0.18 in × 0.25 in|
|2010 footprint||0.197 in × 0.098 in|
|2512 footprint||0.25 in × 0.13 in|
|2920 footprint||0.29 in × 0.20 in|
Does The Capacitor Size Matter?
It is handy to understand what a capacitor is before asking does the size and dimensions matter.
While you may have an 0402 component size of 0.039 in × 0.020 in, updates to the system may mean you need updates to your capacitor.
Besides this, one thing is, if you have a capacitor that is too small and it struggles to hold too much voltage passing through it, then it can reduce its life.
What is an SMD capacitor?
The SMD capacitor is just a capacitor with a small footprint and long leads. It has been designed to provide some technological advantages in the operation of high-frequency devices and a benefit for the mass production of electronic devices and gadgets.
Most modern circuits and component descriptions use the F, nF, and pF nomenclature to show the value of capacitors.
Older circuit designs, circuit descriptions, and even the components themselves may use a wide range of non-standard acronyms that aren’t always easy to tell apart.
The main differences between the various capacitance sub-multiples are as follows:
Micro-Farad, µF: Larger value capacitors, such as electrolytic capacitors, tantalum capacitors, and even some paper capacitors measured in micro-Farads, may have been labeled with uF mfd, MFD, MF, or UF.
These words all refer to the temperature in Fahrenheit. This terminology is frequently associated with electrolytic and tantalum capacitors.
Nano-Farad, nF: This submultiple lacked a range of abbreviations because nF or nano-Farads nomenclature was not widely used prior to terminology standardization.
In recent years, the term nanofarad has increased in prominence. However, in certain countries, values are still expressed in large numbers of picofarads, such as 1000pF for 1 nF, or fractions of a microfarad, such as 0.001F for a nano farad.
This terminology is used in ceramic capacitors, metalized film capacitors, surface mount multilayer ceramic capacitors, and even certain modern silver mica capacitors.
Pico-Farad, pF: A variety of acronyms were used to represent the value in picoFarads, pF. The terms used were micro microfarads, mmfd, MMFD, uff, and F. These figures are all in pF.
Picofarad capacitor values are commonly employed in radio frequency, RF circuits, and equipment. As a result, this terminology is most commonly associated with ceramic capacitors; however, it is also applied to silver mica and film capacitors.
The conversion of values from one submultiple to the next has been made easier because to language standardization. It has also resulted in a significant decrease in the likelihood of misunderstanding.
It’s easier to convert from F to nF and pF. When a capacitor value is listed on a circuit diagram in another way on a list of electronic component distributors, this is critical.
What Are The Standard Capacitor Values?
|Common Capacitor Working Voltages (DC), by Capacitor Type|