Abstract: An impulse generator for a fluid meter register is comprised of a rotatable armature which produces a magnetic field and which is intermittently driven by the register gear train against the bias of a spring. When released from the gear train the armature rotates under the influence of the spring, the magnetic field acting on the turns of a coil to produce a voltage pulse in the coil. A release mechanism between the armature and the register gear train is arranged so that the resisting torque applied to the gear train by the spring when the armature is driven against the spring bias, is substantially constant.