There is provided a pulser, a time of flight mass spectrometer system comprising the same, and a method of analyzing the ions using the pulser. The pulser comprises a first positive switch for coupling and decoupling a first electrode of the accelerator assembly to a first positive voltage; a first negative switch for coupling and decoupling the first electrode to a first negative voltage; and, a first bipolar switch for alternately coupling and decoupling the first electrode to a third voltage.