| 摘要 |
PURPOSE:To make short warning sounds as desired which are effective as a countermeasure for noises by turning on a field-effect transistor when a touch switch is on to drive a relay circuit and thereby to sound a horn through a horn switch. CONSTITUTION:When a head touches a touch member of a touch switch TS, a gate G of a FET (field-effect transistor) Q1 receives the voltage from a secondary battery E1 divided between resistances R7, R6 and a resistance (several hundred KOMEGA) inherent to the hand on the basis of a node between resistances R4 and R5. Then, the FET Q1 held in cut-off state is turned on to pass the current to resistances R2, R3 in a relay circuit 3, and a transistor Q2 is turned on to close a switch 2a of a relay Re2. This causes a horn switch 1a of a relay Re1 to be closed and a horn H to which power is supplied through a battery B on board is operated to make a warning sound. |
