The Texas Instruments UA78L15ACLPR is a fixed 15 V positive linear regulator rated for 100 mA continuous output. It comes in a TO-92-3 through-hole package with formed leads — the same footprint as a small-signal transistor, so it swaps into existing board layouts without a bracket. The fixed output means no external resistor divider; just a couple of bypass caps and it is running. Typical jobs: biasing analog front-ends, powering low-current relays, or supplying a stable 15 V rail in industrial control panels and instrumentation.
Dropout voltage is 1.7 V max at 40 mA. PSRR is 39 dB at 120 Hz, which knocks down full-wave-rectifier ripple by about 90x.
Protection set — field-service friendly
Over-current, over-temperature, reverse polarity, and short-circuit protection are all built in. That is the difference between a part that survives a wiring mistake on site and one that pops. For a field swap, the TO-92-3 orientation is obvious — flat face forward, leads down — and it handles a soldering iron without drama. No lab bench needed.