| 摘要 |
PROBLEM TO BE SOLVED: To provide air massage highly satisfactory for a user by accurately controlling an expansion pressure in an air massager for massaging arm parts and leg parts, etc., by the expansion and contraction of an air bag. SOLUTION: When a control circuit 35 performs the duty control of a pump 31 driven by an AC power source 32 to expand the air bag through a drive circuit 33, a zero cross is detected only once per cycle of an alternating current in a photocoupler 37 provided with a single photodiode 38, and one more zero cross in one cycle is prepared in the built-in timer 35a of the control circuit 35. Thus, the detection circuit of the zero cross is simplified, effect due to the dispersion of the detection circuit equally appears in a half cycle of positive polarity and a half cycle of negative polarity, and the expansion pressure is accurately controlled. COPYRIGHT: (C)2006,JPO&NCIPI
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