1N1525A

18V Nominal Zener Voltage, 1.0 Watt power dissipation, ±5% Tolerance (A suffix) Silicon Oxide Passivated Junction Zener Regulator Diode, designed to enforce highly repeatable voltage reference thresholds and low-noise shunt power regulation loops across early transistorized instrumentation decks and automated control boards, housed in a high-reliability hermetically sealed axial-leaded top-hat or metal stud-mount structural casing profile layout. Manufactured by Motorola / International Rectifier. [1]