| 摘要 |
PURPOSE:To lengthen a data transmitting distance by providing a battery in a data memory. CONSTITUTION:In the case where a lithium battery 12 has terminal voltage more than a prescribed level, a transistor Tr2 is conducted and another transistor Tr1 is off. Thus, the battery 12 is not loaded with a power source switch circuit 11 and the like, current is supplied from the battery 12 to each block of a data transmitting means 14 and a data memory can perform data transmission between outer data input and output devices. Since in this case data transmission is performed by making the lithium battery 12 a power source, long distance data transmission can be performed. When the terminal voltage of the battery 12 is suddenly lowered, the voltage of the middle point of resistance R2, R3 is also lowered and the transistor Tr2 is off. When the data input and output device is approached, alternating voltage is induced in an oscillation circuit 1 by electromagnetic induction, the transistor Tr1 is conducted and electric power supply is supplied in each block by a constant voltage circuit 13. |
