A shot of direct current will instantly stop any ac power tool motor. Switch Si is a center-off, one side spring return. With Si on, ac will be fed to the motor and the motor will run. To brake the motor, simply press Si down and a quick shot of dc will instantly stop it. The switch returns to the center off position when released
This Power Brake can only be used with ac motors; it will not brake universal (ac-dc) motors. A heat sink must be provided for the diode.