Abstract:
A relay includes contacts residing within a glass tube. A coil surrounding the tube and a switch are connected in parallel between two terminals of the relay. A current source supplies a current to the coil and switch. When the switch is open, substantially all of the current passes through the coil and the coil produces a sufficient amount of magnetic flux to close the relay's contacts. When the switch closes, it shunts a sufficient amount of the current away from the coil to reduce the magnetic flux it produces below the level needed to keep the contacts closed. The current source is sized so that the coil requires relatively few turns, thereby allowing the relay to be relatively thin. The coil is formed by a conductor embedded in an insulating substrate surrounding the tube.