| 摘要 |
In order to enable, for example, the elderly, to remotely control an electrical device, the operation of an electrical device 27 is controlled in dependence upon the reception of light modulated at 65 Hz by a phototransistor 11. The receiver 18 includes a band-pass filter 22 having a Q of about 50 and being tuned to 65 Hz. The transmitter comprises a tungsten flashlamp bulb 4 which is selectively energized at 65 Hz by operation of a pushbutton 6. The transmitter is in the form of a hand held flashlamp so that it can also be used as a flashlamp. <IMAGE>
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