12 V shunt regulation with ±2% hold
The 1N4742CE3/TR13 is a 12 V zener diode rated for 1 W continuous power dissipation in a DO-204AL (DO-41) axial-lead package. The ±2% tolerance on the nominal zener voltage makes it a tighter-grade part than the standard 5% 1N4742 — relevant when the shunt voltage determines the reference for a downstream regulator or comparator threshold. Maximum zener impedance is 9 Ohms (Zzt at the test current). This dynamic resistance means the regulation voltage shifts about 9 mV per mA of current change through the diode — a factor to budget in the bias resistor calculation if the load current varies.
Temperature grade and package fit
The DO-41 axial body is a standard through-hole footprint — mates with 0.100-inch pitch board holes and common clip or wave-solder assembly. Supplied in Tape & Reel (TR) format for automated insertion; not a bulk or cut-tape quantity. Reverse leakage is specified at 5 µA maximum with 9.1 V applied across the junction — a guard-band check for high-impedance bias circuits where leakage current could shift the operating point.