| 摘要 |
PROBLEM TO BE SOLVED: To obtain a circuit where a battery is used for a long time by supplying the DC output of the battery as the circuit power source of each circuit in a radio tag by means of energizing a radio wave reception time switching element. SOLUTION: Radio wave received by the resonance circuit 2 of a radio tag receiving circuit part 1 is rectified between the base and emitter of a transistor 4 and the switching of the transistor 4 is started. Then the transistor 5 is also switched by the switching of the transistor 11 and the power source is supplied to processing logic or an amplifier circuit 6 in a receiving circuit from the battery 3 with a power source line 7. In this case, the potential of the transistor 4 is kept in L level by a delay capacitor C2 and, besides, FET 1 is arranged for discharging an electric charge remaining in the power source line 7 after turning off the transistor 5 since electric wave is not received. |
