Can I connect an external electret microphone to the iPhone?

edited December 1969 in SignalScope

I'd like to know whether I could connect either a home-made electret microphone made from Panasonic WM-61A capsules or an Audiomatica MIC-01 via an appropriately wired 1/8-inch TRRS plug. Does the iPhone provide sufficient bias voltage for either mic units? Someone else on this forum mentioned that his iPod Touch (2nd gen.) did not recognise a microphone connection unless it was coerced somehow so that the device auto-detected this.

Many thanks in advance.


  • The headset jack of the iPhone and 2G iPod touch provides the proper bias voltage for electret mic in compatible headsets, so you ought to be able to design your own mic that will work. There at least a couple of commercially available microphones that plug right into the headset jack. The bias voltage is around 2.7 VDC and another forum post indicates that a 3.3 k ohm resistor drops that voltage to around 1.9 V.

    Good luck!

  • Additional information regarding headset input is available here and here on the blog.
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