| 摘要 |
An electric tool switch has an operation member turnable in both directions and biased to self-return to a neutral position, a circuit substrate arranged to be orthogonal to a turning shaft of the operation member, a slidably moving element which is pressed against the circuit substrate and which is turned with the operation member to slidably contact the circuit substrate, and an inversion mechanism for switching a polarity between output terminals according to the turning direction of the operation member from the neutral position. The circuit substrate is formed with two sets of variable resistor circuits, which close a circuit when the slidably moving element slidably contacts and which resistance value changes according to a contacting position of the slidably moving element, electrically connected in parallel on both sides in the turning direction from a position corresponding to the neutral position of the operation member. |
