Abstract: Red, green and blue light sources, and a shutter are provided. Photosensors are provided for detecting the luminance of each of the light sources. A controller is provided for sequentially operating each of the light sources, the shutter, and the photosensor in synchronism with each other at regular intervals. A luminance control circuit is provided for comparing a luminance detected by the photosensor with a reference value and for controlling the luminance of each of the light sources based on the comparison so as to keep a color balance of the light emitted from the color display device.

Abstract: An IC card such as cash card is disclosed. The IC card has a RAM, a control circuit for controlling access to the RAM, and a power supply circuit receiving outside energy and supplying power to the RAM and the control circuit. A first voltage detector produces a starting output when supply voltage of the power exceeds a predetermined first reference voltage. A second voltage detector produces a control signal when the supply voltage exceeds a predetermined second reference voltage, which is higher than the first reference voltage. An AND gate is provided to produce a RAM control signal for operating the RAM when the starting signal and the control signal are applied thereto.