The 1.5KE27C-E3/73: The 1.5KE27C-/73 is listed as Obsolete by Vishay. Any stock found will carry the original Vishay date-code and marking; the laser etch and package consistency should be verified against the TransZorb family standard before committing to a large buy.
Clamping ratings and protection fit
This is a 1500 W (1.5 kW) bidirectional Zener TVS diode in the TransZorb series. The 21.8 V reverse standoff voltage means the device does not conduct below that rail — it sits across a 21.8 V or lower supply line without leakage. The 1500 W rating is the peak pulse power dissipation into that waveform; real-world derating applies above 25 °C ambient.
Package and temperature envelope
Through-hole axial package (DO-201AA / DO-27) — the body is the same diameter as the standard 1.5KE series. The bidirectional single-channel configuration means a single device clamps both polarities, saving a diode in the protection stage.