Ebow

The EBow or ebow is a brand name of Heet Sound Products, of Los Angeles, California, for the original type of monophonic handheld electromagnetic string driver, invented by Greg Heet in 1969, first introduced in 1976, and patented in 1978. The name Ebow stands for "Electronic Bow" or Energy Bow) (often spelled E-bow in common usage). The EBow is a battery-powered electronic device for playing the electric guitar. The EBow uses a pickup – inductive string driver – feedback circuit, including a sensor coil, driver coil, and amplifier, to induce forced string vibrations. The Ebow is monophonic, and drives one string at a time, producing a sound reminiscent of using a bow on the strings.

In 1976, Heet Sound introduced the first EBow at the NAMM Show. It featured an internal, string vibration triggered automatic power switch, a chromium-plated ABS plastic shell, a red LED power indicator, and a police-style form fitted black leather holster, embossed with the Ebow logotype. In later years, five subsequent Ebow models were introduced, all of which consisted of internal variations of the original Ebow circuit and actuator coils, as well as color changes to the original plastic shell and Ebow logotype, both of which remained essentially unaltered since the introduction of the Ebow, with the exception of the addition of an external power switch on the back. The latest Ebow model is the "Plus Ebow", which is switchable between "standard mode" and "harmonic mode".

Since the 1990s, various manufacturers have introduced string drivers for guitar and bass, including hand held monophonic and polyphonic string drivers, as well as built-in and surface mounted types, commonly referred to as "Sustainers" or "Resonators", such as Fernandes Guitars (G-401), Sustainiac (Stealth Pro3), and "gooseneck" microphone stand mounted types (Vibesware Guitar Resonators ).

The EBow is used to produce a variety of sounds not usually playable on an electric guitar. These sounds are created by a string driver that gets its input signal by an internal pickup, which works like a guitar pickup. Its output signal is amplified and drives the other coil, which amplifies the string vibrations. With this feedback loop the player can create a continuous string vibration. Fading in and out by lowering and raising the EBow is also possible.

...
Wikipedia