I Built the above Circuit and it works like a charm.
now i want to adjust the circuit to read a range of 0 to 50mV produced from a piezo element under vibration.
also, rather than from a 9V battery, i need this circuit to operate from a 3V supply (2AA batories)
can anyone suggest how i can adjust this to work from 3V
also, do i need to amplify the 50mV signal? if so, how would i do that.
I noticed, the circuit i built draws about 7mA when it's not operating, is there a way to bring it to zero?
any help is appreciated. thanks in advance.