starlet
Junior Member level 2

need to measure the Sound Pressure from 30 to 110 db and display on LCD using PIC 16F877.
on the internet i found using LM358 (pre amp + peak detector) and CA3140 (no high gain, mean preamp) for single supply and TL071 (pre amp) with LF351 (half wave rectifier) with Dual supply.
any idea how to show db values using these circuits and will these work in above sound range and whats the better in these or any other.

on the internet i found using LM358 (pre amp + peak detector) and CA3140 (no high gain, mean preamp) for single supply and TL071 (pre amp) with LF351 (half wave rectifier) with Dual supply.
any idea how to show db values using these circuits and will these work in above sound range and whats the better in these or any other.



