| 摘要 |
There is disclosed a method and apparatus for reducing the power required to activate the soft and playing mechanism of an electronic player piano and similar instruments. In accordance with the invention, full voltage on the solenoid is maintained for a short period of time which is more than sufficient to allow full travel of the solenoid and then the power is reduced by reducing the applied voltage. In accordance with the preferred embodiment, a timer is started when the solenoid is commanded on and then when the timer times out, the command gate signal is turned on and off with a waveform which can be set at a duty cycle sufficient to maintain the solenoid in the held-in position. |
