5.1 V regulation at 1 W
The 1N4733PE3/TR12 is a 5.1 V zener diode rated for 1 W continuous power dissipation in a standard DO-41 axial-leaded package. That 5.1 V nominal is the voltage it holds across its terminals when reverse-biased into breakdown — the regulation point for a shunt reference or a simple clamp rail. With a ±10% tolerance, the actual zener voltage for any given unit falls between 4.59 V and 5.61 V. For a precision reference that spread may be too wide; for a protection clamp or a bias rail it is usually acceptable.
Thermal and impedance profile
Maximum impedance (Zzt) is 7 Ohms at the test current — this is the dynamic resistance in the breakdown region. A lower Zzt means the voltage shifts less with current changes; 7 Ohms is typical for a 1 W, 5.1 V part and keeps the regulation tight enough for most shunt applications. Reverse leakage is specified at 10 µA maximum at 1 V reverse bias — well below the breakdown knee. That low leakage means the diode draws negligible current until the applied voltage reaches the zener region, so it does not load the circuit when operating below the regulation threshold.
Active lifecycle and sourcing
The Tape & Reel (TR) suffix indicates 5,000-piece reel packaging for automated pick-and-place. The base product number 1N4733 covers the same die in bulk or ammo-pack variants if the reel quantity does not match your build volume.