| 摘要 |
An LED-based lighting unit for retrofitting a fluorescent light fixture in a transit vehicle has a concave frame or structure conforming to the shape of the fluorescent lighting fixture cavity, connector pins on either end of the frame for secure attachment to sockets of the fluorescent fixture, a plurality of LED modules for illuminating an area of a transit vehicle, a power adapter for receiving and converting an input power supply signal, and a diffusive lens cover. The frame may have rear fins or other features for facilitating dissipation of heat generated by the LEDs. A controller adjusts the intensity of the LEDs based on a reading from a temperature sensor and on a manual brightness setting. The change in light output may be accomplished by reducing a duty cycle of a pulse width modulated (PWM) waveform supplying the LEDs. |
