7.5 V regulation with ±2% precision
The 1N4737CPE3/TR12 is a 7.5 V zener diode from Microchip Technology, part of the 1N4737 family. Its ±2% tolerance means the actual zener voltage sits between 7.35 V and 7.65 V at the specified test current — tight enough for reference rails and clamp circuits where a standard ±5% part would drift outside the regulation window. Rated for 1 W continuous power dissipation in the DO-204AL (DO-41) axial package, this diode handles steady-state shunt regulation up to that limit. The 4 Ohm maximum zener impedance (Zzt) at the operating point keeps the voltage shift under load small — a 10 mA change in bias current shifts the output by about 40 mV.
Thermal and electrical margins
Reverse leakage is 10 µA maximum at 5 V reverse voltage — low enough to avoid loading the circuit when the zener is not conducting. Forward voltage is 1.2 V maximum at 200 mA forward current, typical for a silicon junction of this die size. The DO-41 body with 0.025-inch diameter leads fits standard 1 mm diameter PCB holes and mates with axial-lead sockets for field replacement.