Disclosed are bandgap circuits that use a resistive divider circuit to modulate the gate voltage of a reference source transistor. Embodiments directed to methods and apparatus for establishing traffic data transmission rates andor transmission power levels between wireless terminals is described. The controller is arranged to sense current during a finite sampling window, move the sampling window from a first window position to a later window position for one or more subsequent injection events; determine a new sampling window position on based a valve movement signal output the two preceding windows; and feedback the new sampling window position for a subsequent injection event. Toner is stirred by continuously rotating the toner bottle in forward and reverse directions. Therefore, the device may continuously tune haptic effect generation according to vibration measurements. Multiple pick-up heads andor multi-socketed programming units can be used.