| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to adjust the sound pressure of a buzzer without PWM control. SOLUTION: The sound pressure variable buzzer driving device where the sound pressure of the buzzer 1 is varied by adjusting a current flowing through the buzzer 1, is provided with plural pieces of circuits in which resisters R1-R4 and transistors Tr1-Tr4 are connected in series, and also a current adjustment part 10, in which the plural pieces of the circuits each are connected in parallel, is connected with the buzzer 1 in series, and further, a microcomputer 6 is provided with plural ports 6a-6d to be connected with respective transistors Tr1-Tr4 arranged for each of the plural pieces of the circuits, and the on-off of the transistors Tr1-Tr4 is controlled by adjusting output voltages of the individual ports 6a-6d based on the input from a sound pressure adjusting means 7. |
