| 摘要 |
PURPOSE:To confirm the depressing operation of a keyboard, by sounding a sound body such as speaker, when a key on the keyboard of a slave device is depressed. CONSTITUTION:When no key button is depressed, an amplifying transistor (TR)12 is cut off and no sound is given from a speaker 17. When th key button is depressed, a TR11 turns on and the emitter of the TR12 is decreased to a ground potential. Then, a trigger signal is given to an IC5, and audible frequency clock pulse determined at a time constant circuit 10 is produced, this clock pulse is given to the speaker 17 via the TR12 and a power amplifying circuit 16, and audible sound is outputted from the speaker 17. |
