# Calculate the appropriate bias voltage (and resistor) of a condenser microphone

I have a condenser microphone that has no any model name or number. As we know condenser microphones need a bias voltage for operation. Some microphones need $2 V$[1]. and some need more. As we can not feed microphone more than its $V_{max}$, is there any way and measuring method to calculate the appropriate bias voltage of it without having its datasheet?

Edit:
What is the appropriate Resistor to build the biasing voltage?

simulate this circuit – Schematic created using CircuitLab

• The website that gave you the information has an area where you can make comments - it's right at the bottom of the page - did you make a comment - this seems a more appropriate "first" action. Also that site said check the data sheets to see what your microphone needs and as they cost less than half a pint of beer I'd have thought buying a new one or, maybe just feeding it via a 2k2 resistor from 5V and seeing what happens would also be a reasonable course of action. You won't need R2 - likely it's got a JFET inside that'll work from 2V to 10V with a resistor (R1) in the range of 1k to 10k – Andy aka Dec 24 '13 at 21:17
• Dear Andy aka, This means I should have seeing eyes, I didn't think about commenting on the website; Although the comment system is loading from google and google banned my region and could not be loaded. – Mohammad Etemaddar Dec 24 '13 at 21:28
• Wow, what region was that if it's not too rude to ask? Regards resistor see my first comment. – Andy aka Dec 24 '13 at 21:54
• @Andyaka: My region is Iran (Persia) :) – Mohammad Etemaddar Dec 24 '13 at 22:15
• So presumably google (search engine) cannot be used in Iran. I'm old enough to rememberber the old Shah of Iran!!! Died of cancer I believe after the revolution in 77? Well, that's the story we got over here. – Andy aka Dec 24 '13 at 22:27