The 731B DC Reference Standard is a versatile instrument providing stability, while utilizing the excellent performance capabilities of solid-state technology. The instrument furnishes a wide variety of prevision voltages with switched output ranges including 1.0, 1.018 + Delta E, 10.0, and Delta E volts. Delta E provides a variable output of 0 to 999 ?V which is either added to the voltage of a standard cell transfer or may be used directly as a low-level, stable direct voltage source.