set to 4 5 volts voltage v 3 at node 132 is set to 1 0 volts and voltage v 4 at node 130 is set to a voltage of 0 5 volts the test circuitry 110 produces clocked signals clkp and clkpb at outputs 128 and 126 respectively which in turn are applied to the inputs 28 and 26 of the microsensor the clocked signals clkp and clkpb have a frequency set by clock signal clk and high and low voltage potential amplitudes set by the selected pairs of voltages v 1 and v 3 or v 2 and v 4 depending on the selected mode of operation referring to fig7 the self test circuit 110 is further shown in a simplified form coupled to exemplary equivalent capacitors cs 1 and cs 2 which generally represent the equivalent electrical circuit of the above described microsensor capacitor cs 1 represents the equivalent sum total of capacitance between electrode 20 a and movable plates 14 and the capacitance between electrode 20 c and movable plates 14 while capacitor cs 2 represents the equivalent sum total of capacitance between electrode 20 b and movable plates 14 and the capacitance between the electrode 20 d and movable plates 14 an operational amplifier a v and capacitor c fb represent an element of the charge to.