These are instruments that make sound using electronic circuits or computers and send the sound to amplifiers. One of the first was the Telharmonium invented in the late 19th century. It was too large to be of any widespread use.

The pencilina was invented and developed by Bradford Reid about 1985 and he has continued developing it since then. The pencilina's two "necks" each have a bridge, tuning pegs, and a set of strings; six strings on one neck are tuned like a guitar and four strings on the other are tuned like a bass guitar. The pencilina is played by striking its strings and bells with sticks. The strings may also be plucked or bowed.


The Theremin was invented by the Russian scientist Theremin about 1920. The instrument is played by bringing your hands close to two antennas which sense the position of the player's hands and control oscillators for frequency with one hand, and amplitude (volume) with the other. The electric signals from the theremin are amplified and sent to a loudspeaker.


The Moog synthesizer was invented and marketed by Dr Robert Moog during the mid 1960's. The video clip contains a good summary.


The Mellotron. The heart of the instrument is a bank of parallel linear magnetic audio tapes, which have approximately eight seconds of playing time each. Playback heads underneath each key enable the playing of pre-recorded sounds. The earlier MKI and MKII models contained two side-by-side keyboards: The right keyboard accessed 18 "lead/instrument" sounds such as strings, flutes, and brass; The left keyboard played pre-recorded musical rhythm tracks in various styles. The instrument was first produced in quantity in 1970. The invention of transistors made it possible for the sample to be digitized and played back electronically. The sampling synthesizer has now largely replaced the true electronic sound synthesizers.


The Reactable (reacting table) reacts to electronic boxes placed on the table to produce music-like sounds. It first appeared in public in 2005.