Abstract: A warning and braking device for use on a power cutting tool such as a circular saw or a lawnmower comprises a generator, a drive shaft and a pulley connected by a lever to the power tool on/off switch. When the power tool is in the working "on" position, the generator assembly does not contact the power tool drive belt and no electric current is produced by the generator. When the power tool switch is shifted to the off position, however, the pulley on the generator drive shaft is brought into contact with the drive belt, exerting a braking force on the drive belt and producing an electrical signal from the generator which is connected to a warning device such as a light or a siren.