optoisolator

optoisolator

[¦äp·tō′ī·sə‚lād·ər] (electronics) A coupling device in which a light-emitting diode, energized by the input signal, is optically coupled to a photodetector such as a light-sensitive output diode, transistor, or silicon controlled rectifier. Also known as optical coupler; optical isolator; optically coupled isolator; optocoupler; optoelectronic isolator; photocoupler; photoisolator.

optoisolator

A device that transfers a signal optically between two electronic circuits, isolating them from each other. An electronic signal on one side is converted to light by a visible or infrared LED. The receiver on the other side detects the light signal and converts it back into electronic format. Optoisolators are used to protect circuits against damage from current surges.