Direct electric action is one of various systems used in

pipe organs The pipe organ is a musical instrument that produces sound by driving pressurized air (called ''wind'') through the organ pipes selected from a keyboard. Because each pipe produces a single pitch, the pipes are provided in sets called ''ranks ...

to control the flow of air (wind) into the organ's pipes when the corresponding keys or pedals are depressed. In direct electric action, the valves beneath the pipes are opened directly by

electro-magnet An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in the ...

solenoid upright=1.20, An illustration of a solenoid upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose ...

s, while with

electro-pneumatic action The electro-pneumatic action is a control system by the mean of air pressure for pipe organs, whereby air pressure, controlled by an electric current and operated by the keys of an organ console, opens and closes valves within wind chests, allowin ...

, the electro-magnet's action admits air into a pneumatic or small bellows which in turn operates the pipe's valve. Other types of actions used in pipe organs are

tracker action Tracker action is a term used in reference to pipe organs and steam calliopes to indicate a mechanical linkage between keys or pedals pressed by the organist and the valve that allows air to flow into pipe(s) of the corresponding note. This is ...

, using mechanical linkage of rods and levers, and

tubular-pneumatic action "Tubular-pneumatic action" refers to an apparatus used in many pipe organs built during the late 19th and early 20th centuries. The term "tubular" refers to the extensive use of lead tubing to connect the organ's console to the valves that control ...

which utilizes a change of pressure within lead tubing which connects the key to the valve pneumatic.

Sources

*William H. Barnes ''The Contemporary American Organ'' (1959) Pipe organ components {{electronics-stub