| 摘要 |
A switch for controlling a rotational speed of a motor includes an operation member, a first circuit, and a second circuit. The first circuit includes a brush coupled to the operation member having a contact and also includes a variable resistive plate having a resistance that changes in response to a contact position of the contact point of the brush, so that the first circuit outputs a control signal to the motor according to the contact position of the contact point. The second circuit connects the brush and the resistive plate without through the contact point when the brush is positioned at a given position relative to the resistive plate. |
