22 V regulation in a hand-solderable package
The 1N6008B/TR is a 22 V zener diode from Microchip Technology rated for 500 mW continuous power dissipation in the DO-35 axial package. The ±5% tolerance on the nominal zener voltage means the actual breakdown sits between 20.9 V and 23.1 V — tight enough for basic voltage reference or shunt regulation in a low-power rail.
Thermal and leakage margins for the bench
Operating from -65°C to 175°C, this diode handles the full military temperature range — useful for a prototype that might end up in an engine bay or outdoor enclosure. Reverse leakage is just 100 nA at 17 V reverse voltage, so standby current in a battery-powered reference circuit stays negligible. Maximum zener impedance is 55 Ohms at the test current. That impedance matters when the diode sees varying load current — the voltage drop across the internal resistance adds to the nominal zener voltage, so the regulation accuracy depends on keeping the bias current steady.
Through-hole build with a friendly footprint
The DO-35 axial body (DO-204AH) is a classic through-hole package — 0.020-inch diameter leads, 0.150-inch body length. You can hand-solder it into a perfboard or a two-layer PCB without magnification; the lead spacing fits standard 0.100-inch grid prototyping boards. The Tape & Reel packaging (1N6008B/TR suffix) is meant for machine placement, but the individual diodes are easily cut from the carrier tape for bench work.