I have two pairs of headsets here and only one works with my PC (the microphone that is). They are both the same pin out, ground is the ring and mic hot is the sleeve.
Without plugging them in, the pair that work with my PC mic in jack have a DC resistance of 1.4K while the other pair (which were made to work with Apple devices) is at 4M. I have a few questions.
Am I just measuring the resistance across the source and drain of the FET inside these microphone capsules? If so, why isn't the resistance much lower since the actual mic inside the capsule is biasing the FETs gate with a static charge?
Also, why do both mics work with an apple product but the one that was designed for Apple products (4M) won't work with a normal PC mic jack. Is the supply voltage different?
Is there a way to design a circuit that forces the apple designed mic to behave like the standard 1.4K mic without opening up the capsules?
Thanks