Abstract: A battery free off-grid solar inverter system includes an inverter and a controller. The inverter is used for converting a direct current voltage provided by a solar panel into an alternating current voltage. The inverter has an input terminal, an output terminal, and a control terminal. The input terminal is used for coupling to the solar panel for receiving the direct current voltage, and the output terminal is used for coupling to a load for coupling the alternating current voltage. The controller is coupled to the control terminal for gradually increasing the alternating current voltage to make the direct current voltage be gradually decreased when the battery free off-grid solar inverter system is turned on. The controller stops increasing the alternating current voltage when the direct current voltage is lower than a predetermined direct current voltage value.

Abstract: An illuminated keyboard and an illuminating method for a keyboard are disclosed. The illuminated keyboard includes an illumination module, a first sensing module, a second sensing module, and a control module. The first sensing module is used for sensing an ambient light. If the brightness of the ambient light is less then a reference brightness, the first sensing module generates a first signal. The second sensing module is used for sensing a state of touch on the illuminated keyboard and generating a second signal according to the state of touch. The control module is connected to the illumination module, the first sensing module, and the second sensing module respectively for driving the illumination module to emit light according to the first signal and the second signal.

Abstract: A light emitting keyboard module including a light emitting keyboard and a control transmitting module is provided. The control transmitting module includes a transmitting unit, a timing unit, a comparing unit and a processing unit. The transmitting unit communicates with the light emitting keyboard by signals. The timing unit counts a stop time of the light emitting keyboard. The comparing unit compares the stop time with a predetermined time, and generates a comparing signal when the stop time is greater than the predetermined time. The processing unit drives the light emitting keyboard to enter a power saving mode after receiving the comparing signal.