| 摘要 |
PROBLEM TO BE SOLVED: To prevent a device from uselessly consuming power. SOLUTION: A signal reproduction section 21 generates a sound signal and supplies the signal to a driver unit 15 of a headphone 10 via a signal amplifier section 22. A transistor(TR) 31 amplifies an electric signal produced in a sensor section 11a when a user wears the headphone 10 and the TR 31, a resistor 32 and a capacitor 33 or the like are used to convert the signal into a signal with a DC level to drive a TR 35. When the user wears the headphone 10, the TR 35 is conductive and when the user takes off the headphone 10, the TR 35 is nonconductive. When the TR 35 changes from its on-state into its off-state while operating an acoustic reproducing device, power supply from the power supply section 52 to a signal reproduction section 21 and the signal amplifier section 22 is stopped to automatically terminate the operation of the acoustic reproduction device.
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