Capacitors, Capacitors, Everywhere!By Robert Cong
What's the difference between capacitors?One of the most common passive component questions we hear is "What are the differences between the wide varieties of capacitors?" When your schematic calls for a capacitor, you have many choices: electrolytic, ceramic, silver mica, mylar, monolithic, tantalum, glass or supercapacitors, just to name a few. It can be confusing, especially if you have a specific application that requires extra noise filtering or high voltage handling capabilities. Below are some common types of capacitors and what applications they are most often used in:
Made of ceramic material as the dielectric and metal as the electrodes, ceramic capacitors come in a variety of shapes and sizes. They are generally less expensive than other capacitors and carry lower capacitances (couple of µF max.), which makes them used often during low capacitance requirements in noise/harmonics filtering and suppression applications. Multiple ceramic layers may also be arranged and compressed together to form a block, reducing equivalent series inductance and creating a monolithic ceramic capacitor.
Using polystyrene film as the dielectric, these capacitors provide high insulation, low distortion, high frequency ranges and good temperature stability. They usually come in a through-hole package, so surface mount packaging is not available. They are widely used in audio applications such as ham radio for EMI/noise filtering and RF coupling.
Silver Mica Capacitors
1000pF Silver Mica Capacitor
Silver mica capacitors have low tolerance levels providing highly accurate and stable performance. The mica dielectric contains thin sheets of silver foil in between to provide a chemically stable structure that does not react to many environmental substances. Greatly used in tuning circuits and harsh environments, silver mica caps are the ones to use for high performance applications that require the most accuracy and dependability.
Of course, every capacitor can be used in many different applications. It just so happens that certain ones do better in some applications than others. Did we forget to mention your favorite cap? Tell us what your favorite type of capacitor is and what applications you use it for on our community forum.
Robert is a graduate from Cal Poly, San Luis Obispo in Electrical Engineering. His interests include sports, movies, music and playing with cool, new gadgets.