| 摘要 |
A sensing system for sensing user contact with a saw blade. The sensing system includes an electrode situated adjacent the saw blade that creates a capacitor in series with the capacitance of the blade to ground to form a first leg of a bridge circuit. A reference capacitor is connected to the first leg to form a second leg of the bridge circuit. A voltage source is coupled to the bridge to selectively energize the-bridge. Contact of the blade by a user is sensed when the bridge is unbalanced due to the increase in the capacitance of the blade to ground caused by the user's contact with the blade.
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