Signal original form to a waveform expressed as a current ("I") or a voltage ("V"), or an electromagnetic waveform, for example, an optical signal or radio transmission. Once expressed as an electronic signal, the signal is available for further processing by electrical devices such as electronic amplifiers and electronic filters, and can be transmitted to a remote location by electronic transmitters and received using electronic receivers. In Electrical engineering programs, a class and field of study known as "signals and systems" (S and S) is often seen as the "cut class" for EE careers, and is dreaded by some students as
Electronic drum drum shells made of various materials, often with a rubber/silicone or cloth-like coated playing surface. Each pad has a sensor that generates an electric signal when struck. The electric signal is transmitted through cables into an electronic or digital drum module ("brain" as it is sometimes called), synthesizer or other device, which then produces a sound associated with, and triggered by, the struck pad. The sound signal from the drum module can be plugged into a keyboard amp or PA system for use in a live band performance or listened to with headphones for silent practice. Since digital drums have