摘要:
A dual mode light source unit (3) for an aircraft is configured to be secured into a socket for an incandescent navigation light bulb. The unit has electric circuitry configured to process the input current from the socket and based thereon operate in either civilian, visible mode or covert IR mode. When the current is in one electrical state, or a certain voltage level, the circuitry sends power to the visible light source (13). When the current is in a different state, the circuitry sends power only to the IR source (15). All control may be accomplished over a single pair of wires, as in existing systems that do not have IR mode capability. To upgrade existing aircraft, light source units (3) according to the invention are inserted into the existing navigational light sockets.