Abstract: A method and apparatus for providing a lower frequency signal with reference to a higher frequency signal are disclosed. The apparatus of the invention comprises an oscillating signal generator, an integer logical divider, and a signal combiner. The signal generator receives an input voltage and, in response thereto, generates a first output oscillating signal and a second output oscillating signal, both having a first frequency. The two oscillating signals are separated by a ninety-degree phase shift. The integer logical divider receives the two oscillating signals and provides two output divided signals in response. The first divided signal is representative of the first oscillating signal except that its frequency is one-third the frequency of the first oscillating signal. Likewise, the second divided signal is representative of the second oscillating signal except that its frequency is one-third that of the second oscillating signal.

Abstract: A safety device for a tool powered by an electric motor. It has a main switch, electronic controls, and a tachometer-generator. In order to provide a device for switching off a motor as a function of motor speed that is simple and economical and that will retain the same nominal switch-off value for the total life of the device, a relay is wired in parallel with the motor and controls the supply of power to the motor through a relay contact.