silicon planar zener diode. 0.5 W. Zener voltage range Vznom = 130 V, Izt = 1 mA for Vzt . silicon planar zener diode. 0.5 W. Zener voltage range Vznom = 150 V, Izt = 1 mA for Vzt . 0.5W silicon planar ZENER DIODES 25 A standard and Snubberless" triacs silicon planar zener diode. 0.5 W. Zener voltage range Vznom = 200 V, Izt = 1 mA for Vzt .