| 摘要 |
PURPOSE:To eliminate the use of an auxiliary power supply and to miniaturize a display device by using a display element at a display part so as to keep the display even after a power supply is cut off and reading optically the display when the power supply is applied again to preset the contents of the display to a counter. CONSTITUTION:When a power supply is cut off, the circuit operations are all discontinued. The counter value stored in a counter circuit 32 is also erased. However a display part 2 keeps a display state even after the power supply is cut off owing to use of a memory type liquid crystal. When the power supply is applied again, the circuit is actuated again. Then a detection signal is delivered from a power supply circuit 48. The Q output of an FF56 rises up to ''H'' to open a gate circuit 46 and to actuate a luminous body 10. A photodetecting part 26 reads the glowing segments, an encoder 42 converts the read signal into the binary count value corresponding to said read signal. Then the circuit 32 is preset by a preset circuit 44. As a result, the display value shown when the power supply is cut off is preset to the circuit 32. |
