| 摘要 |
PROBLEM TO BE SOLVED: To provide a shock noise prevention circuit that prevents generation of a noise component caused by an unstable output produced transiently in a power supply in a prescribed sound signal system even when the power supply changes from an off state to an on state or vice versa. SOLUTION: A 1st time constant circuit and a 2nd time constant circuit are connected between a positive power supply and a negative power supply. The 1st time constant circuit is configured by connecting a capacitor C3 between the negative power supply and the connection point of a series circuit comprising resistors R1, R2, and the 2nd time constant circuit is configured by connecting a capacitor C6 between the positive power supply and the connection point of a series circuit comprising resistors R8, R9. A coupling circuit that supplies a 1st time constant signal having a level C and caused at the connecting point between the resistors R1, R2 and a 2nd time constant signal having a level B and caused at the connecting point between the resistors R8, R9 to the control terminal of a switching device (transistor (Tr) 3) in common via Trs 2, 3, is configured of diodes D1, D2.
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