electrical relay, which is intended to be energized by a quantity, the value of which is either within its operative range or effectively zero NOTE - 'All-or-nothing relays' include both 'elementary relays' and 'time relays'. Found on http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=444-01-02
An electrical relay which is intended to be energized by a quantity, whose value is either higher than that at which it picks up or lower than that at which it drops out. Found on http://www.youngco.com/young2.asp?ID=4&Type=3