An electrical device like this requires a reverse leakage current of 5μA @ 27.4V.While the device is operating, the maximum voltage - Zener (Nom) is reduced to 36V.For operation, diode reaches 1.1V @ 200mA at the maximum voltage - Forward (Vf).
1N974A Features
reverse leakage current of 5μA @ 27.4V 5μA @ 27.4V is the maximum voltage (Tol)
1N974A Applications
There are a lot of Microsemi Corporation 1N974A applications of zener single diodes.