When I was working on the capacitors section for the next version of Common Parts Library , I realized that it would be helpful to explain why one might pick one capacitor type over another. This information is important because there are a lot of factors (temperature characteristics, package, etc.) which might make a type of capacitor (electrolytic or ceramic) better than others for your project.

In this blog, we will explain all the different types of capacitors, their merits and demerits, and popular applications. We have included some recommendations for commonly used capacitor series with high supply chain availability from

Common Parts Library

and Seeed Studio’s

Open Parts Library

and linked to pre-created searches on Octopart , such as the following for

50V rated Panasonic’s ECA-1HM series for 10µF to 3300µF

:

This is the

: a deep-dive into selecting the correct capacitor for your project. Let’s dive into the world of capacitors:

Capacitors

Capacitors are two-terminal components used for filtering, energy storage, voltage spike suppression, and many other applications. In their simplest form, they consist of two parallel plates separated by an insulating material called a

. Capacitors store electrical charge. The unit of capacitance is

attributed to Michael Faraday who was a pioneer in using capacitors for practical applications.

Capacitors can either be

or

. Polarized capacitors — nearly all electrolytic and tantalum capacitors — can only be connected one way in a circuit: if the “-” terminal goes above “+” terminal, it could lead to a short. Non-polarized capacitors — ceramic, mica, and film capacitors — can be connected either way in a circuit, so they are suitable for AC.

Even though capacitors are so commonly used, it can be tricky to select one for your project. While you might know what

or

your project requires, capacitors have lots of other characteristics — such as

,

, equivalent series resistance (

) and so on — that might make them a great (or poor) choice for your project. The most popular types of capacitors are presented below with this in mind.

There are several different types of capacitors which differ by polarity, performance and cost. Below are some of the common capacitor types:

and

, along with their characteristics, applications, package information as well as info on part selection.

I. Aluminium Electrolytic Capacitors

Aluminum Electrolytic Capacitors are

, so they cannot be used with AC. They can achieve high capacitance value but with large variations, typically 20%.

These are useful in applications which do not need tight tolerances or AC polarization. They are most commonly used in power supplies for

i.e. to reduce voltage ripple reaching the circuit. They are also used widely in

Available in through-hole as well as surface mount package.

6.3V rated

Panasonic’s ECA-0JM series

for 220µF to 22000µF.

50V rated

Panasonic’s ECA-1HM series

for 10µF to 3300µF.

6.3V rated

Panasonic’s EEE-HD0J series

for 330µF to 1000µF.

50V rated

Panasonic’s EEE-HD1H series

for 1µF to 100µF.

II. Ceramic Capacitors

There are two main types of ceramic capacitors: Multi-layer chip capacitors (MLCCs) and ceramic disc capacitors. MLCCs are very widely used in electronic devices and are popular because they have

and

. They have lower Equivalent Series Resistance (ESR) and variation compared to electrolytic or tantalum capacitors but can achieve lower capacitance (only up to a few µF) . Because of high packing densities, MLCC capacitors provide a size advantage and are great for printed circuit boards

(PCBs).

Since these are

they can be be used with AC. They are widely used as a ‘general-purpose’ capacitor and used for high frequency blocking, filtering, oscillator tuning and EMI suppression.

are accurate (+/- 5%) and temperature-compensated- they have very low change of capacitance with temperature.

are popular, and have a tolerance of 30ppm/K, but are available only up to the nanoFarad (nF) range. Because they are very stable and accurate, they are used in frequency control applications such as resonant circuits for radio applications.

are less accurate but provide higher volumetric density (up to µF range) and hence suitable for smoothing or decoupling applications.

Also, they have a large voltage coefficient - a 50% decrease in capacitance value at half the maximum VDC is common.

: Can operate from -55C to 85C with variation of +/- 15%

: Can operate from -55C to 125C with variation of +/- 15%

: Can operate from -30C to 85C with variation of +22/-82%

0201, 0402, 0603, 0805, 1206 and 1812 packages are most common. The numbers represent the dimensions in imperial system, with 0402 being 0.04 X 0.02 inches and 0603 being 0.06 X 0.03 inches and so on.

0402

Yageo’s CC0402JRNPO9 series

for 10pF to 1nF

0603

Yageo’s CC0603JRNPO9 series

for 8pF to 2.7nF

0402

Yageo’s CC0402KRX7R9BB series

for 100pF to 10nF

0603

Yageo’s CC0603KRX7R9BB series

for 100pF to 100nF

0603

Yageo’s CC0603KRX7R7BB series

for 100nF to 1µF

Kemet’s C315C series

for 1pF to 1µF

III. Tantalum Capacitors

These are a subtype of electrolytic capacitors and are

Care needs to be taken as they are known to have catastrophic failure modes which can be triggered by voltage spikes even slightly more than rated voltage. They can achieve high capacitance value and are very stable over time. They are smaller in size than aluminum electrolytic capacitors of the same capacitance but can handle lower maximum voltages.

Due to their low leakage current, stability, and high capacity, they are common for

which rely on low leakage current to achieve long hold duration. They are also used in power supply filtering due to their smaller size and long term stability.

Available in through-hole as well as surface mount (SMD) packages but SMD packages are more popular. In imperial system:

Series A corresponds to size 1206 (this corresponds to dimensions 0.12 X 0.06 inches)

Series B corresponds to size 1210

Series C corresponds to size 2312

Series D corresponds to size 2917

AVX’s TAJA series

for 1µF to 10µF

AVX’s TAJB series

for 10µF to 47µF

AVX’s TAJC series

for 47µF to 220µF

AVX’s TAJD series

for 220µF to 680µF

IV. Film Capacitors

Film capacitors are

which makes them suitable for AC signal use. They have low Equivalent Series Resistance (ESR) and self-inductance (ESL) and are used in

They can handle

and

can thus be used as

to “snub” inductive kickback voltage spikes in DC-DC converters.

TDK’s B32 series

for 1nF to 10µF

V. Mica Capacitors

Mica capacitors are

have low losses, high stability, and have

They are useful for radio frequency circuits. Mica capacitors can cost a few dollars per piece, so they are being replaced by ceramic capacitors for low-power applications. However, they remain critical for high power applications such as

due to their

.

CDE’s

MC series

for 1pF to 1nF (SMD) and

CDE’s CD series

for 1pF to 10nF (Through-Hole)

VI. Polymer Capacitors

Polymer capacitors are

just like other electrolytic capacitors but have several advantages such as

due to lower ESR and longer lifetime. For conventional aluminium electrolytic capacitors, there is a risk of electrolyte dry-out at lower temperatures, but due to the use of solid polymer material as dielectric, polymer capacitors have

even at very low temperatures.

Polymer capacitors are used in place of electrolytic capacitors for

and

.

Panasonic’s OS-CON series

for 3.3µF to 2700µF

This guide covers some of the most popular types of capacitors. Apart from these, there are

which all have unique advantages in either capacity, reliability or tuning ability. However, in most electronic projects you are likely to see one of the six types that we have discussed in this guide. If you have any comments or suggestions on the part selection, drop us a note in our Slack chat room or in comments below. A guide on how to select resistors and inductors is coming next. Stay tuned!

Both MLCCs and ceramic disc capacitors are further divided into two application classes:Update: March 23, 2016 4:48 PM - this article has been edited to include contributions from users online.