i need o\p 210-240 v ac if greater than or lesser than this value i have to turn off relay???
i used 220-12v transformer & rectifier & voltage divider to give 2.5 volt for 230v ac but relay should be turn on if adc value is between 2.4 to 2.6 ie(210-240) diff is +-0.5 which is difficult & inaccurate...
i need some other idea to measure ac & disp in lcd
First of all, how did you subtract 2.4 from 2.6 and get +/- .5? Secondly, if 230V gives 2.5V, then 210->2.3V not 2.4. Maybe your whole problem can be traced to arithmetic.
You've got a 300mV differential, this is well within the capabilities of even a simple 8-bit ADC to resolve. If you've got enough filtering, I don't see where your problem is.
using transformer input is 220 o\p 12 volt rms. bridge drop is 1.4v [full wave rectifier] so o\p is 10.6 volt...
how to find the filter capacitor needed ?
10.6 volt rms after filtering i should get 10.6*sq.root (2)=14.9 volt but getting 8.98v.....in proteus. y???
using transformer input is 220 o\p 12 volt rms. bridge drop is 1.4v [full wave rectifier] so o\p is 10.6 volt...
how to find the filter capacitor needed ?