A relay is an electrically operated switch. Many relays use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits, repeating the signal coming in from one circuit and re-transmitting it to another. Relays were used extensively in telephone exchanges and ...

| rev2 = Robert Christgau | rev2Score = A− | rev3 = The Rolling Stone Album Guide | rev3Score = }} Eponymous is the first greatest hits and the second compilation album by American alternative rock band R.E.M., released in 1988. It was their last authorized release on I.R.S. Records, to whom they had been contracted since 1982, having just signed with Warner Bros. Records. Eponymous is notable for its inclusion of several rare or alternative versions of known tracks. Spanning from the Chronic Town EP to the previous year's breakthrough hit album Document, Eponymous provides a fair overv...