The
electrolytic detector, or
the bare-point electrolytic detector as it was also called, was a type of
detector (
demodulator) used in early
radio receivers. First used by Canadian radio researcher
Reginald Fessenden in 1903, it was used until about 1913, after which it was superseded by
vacuum tube detectors such as the
Fleming valve and the
Audion. It was considered very sensitive and reliable compared to other detectors available at the time such as the
magnetic detector and the
coherer. It was one of the first
rectifying detectors, able to receive
AM (sound) transmissions. On December 24, 1906, US Naval ships with radio receivers equipped with Fessendon's electrolytic detectors received the first AM radio broadcast from Fessenden's
Brant Rock, Massachusetts transmitter, consisting of a program of Christmas music.