A wireless microphone system consists of three main components: an input device, a transmitter, and a receiver. The input device provides an audio signal that can be transmitted by the transmitter. It can be a microphone, such as a hand-held Shure "vocalist" microphone, or a "tie clip" microphone. For wireless systems designed specifically for electric guitars, electric guitars are themselves input devices.
The transmitter handles converting the audio signal to a radio signal and broadcasting it over the antenna. The antenna can extend from the bottom of the transmitter or it can be hidden. The strength of RF signals has restrictions in various countries. The effective distance that the signal can be transmitted is between 30m and 300m, depending on the conditions of use.
There are two basic types of transmitter. A so-called "belt-type" transmitter, which is the size of a box of cigarettes, can be stuck on a belt. When used on a musical instrument, the transmitter can often be stuck on the strap of the instrument or directly on the trumpet or saxophone. Another is a handheld wireless microphone whose transmitter is in the handle of the microphone so that the size of the wireless microphone is only slightly larger than a standard wired microphone. Typically, handheld wireless microphones have a variety of "heads." All wireless transmitters require a battery, usually a 9-volt alkaline battery.