Mosaic
Well-Known Member
Hi all:
I'd like to use a 2.2k Impedance electret mic sampled by a pic 12f675 adc.
I am only interested in sound levels as a sound switch.
I am currently using a 12mm diameter murata piezo 'buzzer' as the input and that works ok. The piezo has a high multimegohm impedance.
I have some size constraints so i am looking at a 6mm electret like this:
https://www.electro-tech-online.com/custompdfs/2012/01/25R0613.pdf
Since I am using ambient cancelling code in the PIC I don't mind the dc offset so I am eliminating the input cap. The supply is a 3.6 V Li ion batt. The RL resistor is a 3.9K.
Now since the rated impedance of the electret is 2.2k and the supply resistor is 3.9k does this mean i will get a dc offset of 2.2/3.9 * 3.6v on the PIC adc?
I'd like to use a 2.2k Impedance electret mic sampled by a pic 12f675 adc.
I am only interested in sound levels as a sound switch.
I am currently using a 12mm diameter murata piezo 'buzzer' as the input and that works ok. The piezo has a high multimegohm impedance.
I have some size constraints so i am looking at a 6mm electret like this:
https://www.electro-tech-online.com/custompdfs/2012/01/25R0613.pdf
Since I am using ambient cancelling code in the PIC I don't mind the dc offset so I am eliminating the input cap. The supply is a 3.6 V Li ion batt. The RL resistor is a 3.9K.
Now since the rated impedance of the electret is 2.2k and the supply resistor is 3.9k does this mean i will get a dc offset of 2.2/3.9 * 3.6v on the PIC adc?