Electronic cymbals and a drum trigger module can be added to any drum set to expand the range of available sounds. Most of these cymbals can be divided into two major types: acoustic electric and pads. Like acoustic cymbals, the electronic kind are also categorized according to their functions within the kit and their sizes.
Most electronic cymbals are either pads or acoustic electric devices. Pads are typically made of synthetic, rubber-like materials and are available in a range of colors. While some pads provide similar functionality to acoustic cymbals, such as rebounding and swing, others do not. Acoustic electric cymbals, on the other hand, are composed of electronic components, like microphones and pickups, and the same materials that are used to make acoustic cymbals, allowing them to produce the same sounds as their acoustic counterparts. The cymbal's surface is usually perforated or coated with a dampening material to reduce its volume, and microphones are typically used to bring up the volume during acoustic performances.
Most, if not all, companies that manufacture electronic cymbals categorize their products according to their musical function. Some commonly available cymbals include the hi-hat, crash, and ride. The hi-hat is usually smaller than the crash and ride, and is used to keep time. It consists of a matching pair of cymbals that can be opened and closed using a foot trigger. The crash comes in a variety of sizes and is used for adding accents, while the ride is typically the largest cymbal, allowing it to provide a full sound and a rhythmic pattern.
Each type of electronic cymbal varies in size. For example, some companies sell hi-hats in two or more sizes. Since electronic cymbals trigger sounds from a drum module, their sizes don't affect the sound that is produced. The size, however, does affect the way the cymbal feels when the drummer hits it with a stick, mallet, or other instrument. Drummers typically select cymbal sizes according to how they feel.
Some electronic cymbals are categorized according to their trigger zones. The trigger zone is the area a drummer hits to trigger a sound from the drum module. A cymbal containing one zone allows the drummer to produce one main sound, while an electronic cymbal containing multiple zones allows the drummer to trigger one sound per zone. Each zone can be mapped to completely different sounds or to variants of the same sound, allowing the musician to reproduce the sound of an instrument more realistically.
In addition to being classified by zones, some cymbals are categorized by their ability to emulate the physical qualities of an acoustic cymbal. An electronic cymbal that has swing, for example, moves back and forth, and up and down, like an acoustic cymbal. It might also provide similar rebounding action. An electronic cymbal with choke can be hit with a drumstick and then quickly silenced by the musician's hand, similar to an acoustic cymbal.