during an ink drop test cycle the relatively high electric field between the print head 10 and the sensing element 14 cause the accumulation of electrical charge in the portions of the ink drops 12 closest to the sensing element 14 as they shear away from a nozzle of the print head 10 as each of the ink drops 12 separates from the print head 10 it retains its accumulated electrical charge each of the ink drops 12 thus transports its induced charge to the sensing element 14 as a consequence each of the ink drops 12 imparts a spike or pulse of electrical charge onto the sensing element 14 as it makes contact these spikes or pulses on the sensing element 14 are ac coupled through an input capacitor c in to an input of the sense amplifier 16 the sense amplifier 16 generates an output signal 40 in response to the electrical voltage imparted onto the sensing element 14 by the bursts of the ink drops 12 the sense amplifier 16 amplifies the pulses and provides some filtering the sense amplifier 16 is a relatively low cost amplifier which does not have enough sensitivity or speed to detect individual ones of the ink drops 12 in one embodiment the sense amplifier 16 is realized with a two stage single supply operational amplifier implemented on a cmos integrated circuit.