The 1N4742PE3/TR8 is a 12 V Zener diode from Microchip Technology in the industry-standard DO-204AL (DO-41) axial-lead package. Its primary job is to provide a stable 12 V reference or clamp voltage in a circuit, with a power dissipation ceiling of 1 W that sets the thermal budget for the application. The ±10% tolerance on the nominal 12 V means the actual Zener voltage for any given unit falls between 10.8 V and 13.2 V at the test current. For a voltage reference circuit, this tolerance band determines the initial accuracy; for a clamping or protection application, it defines the voltage at which the diode begins to conduct.
Thermal and leakage performance across temperature
The 5 µA maximum reverse leakage at 9.1 V confirms low standby loss — important in battery-powered or energy-harvesting circuits where every microamp counts. Maximum impedance (Zzt) is 9 Ohms at the Zener test current. Lower impedance means tighter regulation as the current through the diode varies, so this figure matters when the diode must hold a stable voltage across a changing load.
Supplied in Tape & Reel (TR) format, the DO-204AL (DO-41) axial-lead body is a through-hole package designed for automated insertion or hand soldering. The axial leads suit point-to-point wiring, perfboard, or PCB through-holes with a standard 0.100-inch lead spacing.
Active lifecycle — no end-of-life concern
Microchip Technology lists this part as Active in production.