ABSTRACT
Zener diode Special kind of diode that permits current to flow in the forward direction as normal, but also allows it to flow in the reverse direction when the voltage is above a certain value-the breakdown voltage, known as the Zener voltage. See also: Avalanche diode; Diode; Schottky diode
Zenith angle Angle between the direction of interest, such as the Sun, and the zenith (directly overhead).
