exactly 12 times the frequency of flip flop 32 this provides the timing and accordingly enables the eight bit analog to digital converter 38 to sample the line twelve times for each cycle the analog sine wave is obtained from transformer 10 and fed to sample and hold circuit 36 the eight bit analog to digital converter 38 samples the sine wave every 30 u00b0 thus 12 times per cycle this eight bit digital word is fed as an input to a shift register 40 which has 144 stages such that when the shift register is full a further input or the 145th input will cause the first input to shift out the seven cycle counter of the counter and control circuit 42 is started by the receipt of an interrupt after seven cycles the counter output blocks the shift register clock pulse and puts the shift register in the recirculate mode so that we have five cycles of information before the interrupt and seven following the interrupt thus valuable diagnostic information is stored in the shift register further details on the inventive features in the above described utility monitor will be given below particularly in the detailed way that the peak voltage sensors 14 and 24 operate and more particularly the way the threshold indecision is removed also details will be given on the combination of the digital to analog converter with the peak voltage sensors 14 and 24 to set the reference when a new voltage or different voltage reference threshold is.