Abstract: A light-induced luminous keyboard includes a keyboard main part, a power supply, and a first circuit, a second circuit and a third circuit parallel to each other. The above circuits include two transistors and a negative coefficient photoresistor. While being played in a decreasing light intensity environment, the light-induced luminous keyboard has an increased resistance of a negative coefficient photoresistor and thus an increased voltage is divided for the negative coefficient photoresistor, the point that the base of the first transistor is connected with the first circuit is in a high level, thus the first transistor is available, the point that the base of the second transistor is connected with the second circuit is drawn down to zero volt, the second transistor is available, the luminous apparatus is turned on and the keyboard illuminates. Therefore, automatic illumination of the keyboard is implemented dependent on environmental light intensity.

Abstract: A light-induced luminous keyboard includes a keyboard main part, a power supply, and a first circuit, a second circuit and a third circuit parallel to each other. The above circuits include two transistors and a negative coefficient photoresistor. While being played in a decreasing light intensity environment, the light-induced luminous keyboard has an increased resistance of a negative coefficient photoresistor and thus an increased voltage is divided for the negative coefficient photoresistor, the point that the base of the first transistor is connected with the first circuit is in a high level, thus the first transistor is available, the point that the base of the second transistor is connected with the second circuit is drawn down to zero volt, the second transistor is available, the luminous apparatus is turned on and the keyboard illuminates. Therefore, automatic illumination of the keyboard is implemented dependent on environmental light intensity.