- average the measurement in the digital domain, ultimately over multiples of the mains period. 100 ms averaging time is used by most multimeters, works both for 50 and 60 Hz.
if you need very accurate and without ripples means put a transformer and a bridge rectifier that will be very stable and no ripples... and you wont need a opamp circuit...
if you need very accurate and without ripples means put a transformer and a bridge rectifier that will be very stable and no ripples... and you wont need a opamp circuit...
i have placed bridge rectifier at ac mains and use voltage divider of 1M and 10k to drop the voltages at the output i have used voltage follwer opamp circuit. at the output of voltage follower i have placed 10k resistor in series and capacitor in parallel of 10uf. i have set the oscilloscope to ac input and placed the probe after the resistor at capacitor terminal there are ripples of 100mV p-p with no specific waveform....
put a 220nf cap before 1 meg after rectifier (Caution high voltage capacitor). put a diode before the feedback (precision rectifier). connect a 22k parallel to 100uf...
put a 220nf cap before 1 meg after rectifier (Caution high voltage capacitor). put a diode before the feedback (precision rectifier). connect a 22k parallel to 100uf...
no nothing different......
really i became sick of this
i also tried to measure ac by dropping it by voltage divider then i increased its level to 2.5V ..... in this case i am able to take samples after 0.444 ms (in proteus) and for 50 hz wave the time for one cycle would be 20ms and no of samples would be 45....
so i take each adc value divide it by 100 and added to previous values (in first cycle initial value is kept zero) i added upto 100 values for the average ....and displayed the measured value on 7 segment ....
still the values are unstable...........................
can any one can suggest code or algorithm that can solve my problem
thankssss