The 1N4742APE3/TR12 is a 12 V zener diode from Microchip Technology, rated for 1 W continuous power dissipation in a DO-204AL (DO-41) axial-lead package. The 12 V nominal zener voltage with ±5% tolerance means the regulation knee sits between 11.4 V and 12.6 V — tight enough for most low-power shunt regulator or overvoltage clamp applications. The 1 W power rating sets the maximum steady-state current the diode can handle: at 12 V, that is roughly 83 mA before the junction exceeds its thermal limit. The wide operating temperature range of -65°C to +150°C makes it suitable for industrial or automotive environments where the ambient temperature swings well beyond the commercial range.
Package and board-fit — DO-41 axial leads on tape and reel
The DO-204AL (DO-41) package is a standard through-hole axial-lead format. The leads are 0.025-inch diameter tin-plated copper, spaced 0.300-inch apart when formed for PCB insertion — a common footprint shared with 1N400x rectifiers and other DO-41 diodes. The Tape & Reel (TR) packaging is intended for automated insertion equipment; the reel quantity is set by the manufacturer and confirmed at order. The maximum forward voltage is 1.2 V at 200 mA — this is the drop when the diode is forward-biased, not the zener regulation mode.