There are no sound holes such as those used to amplify string vibrations in acoustic guitars.

An electro-magnetic pickup turns the string vibration into an electric current.

Electric violins have a magnetic or piezoelectric pickup that converts string vibration to an electric signal.

Frets let the player stop the string consistently in the same place, and don't dampen string vibrations as much as fingers alone.

It is generally thought that non-tremolo bridges offer better transfer of string vibration into the body.

The technique is mainly used on electric instruments, because these have a pickup that amplifies only the local string vibration.

In acoustic guitars, string vibration is transmitted through the bridge and saddle to the body via sound board.

To amplify the EUB, the string vibrations are sensed with a 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.