I am building a device that will connect to an Android smartphone 3.5mm jack and was wondering if my device would drain the battery. When checking the current on the microphone line on headset connected to the device I notice there's a current of 0.17mA on that circuit, regardless if the mic is in use or not. Should that affect the battery drain of an average smartphone? Meaning, is there a difference to battery life whether a microphone headset is connected or not?


  • \$\begingroup\$ Could you explain how did you measure the current drawn by the microphone ? \$\endgroup\$ – robomon Dec 22 '13 at 17:27
  • \$\begingroup\$ I connected a fluke on the mic line and measured the current running through it. (had to sacrifice the headphones...) \$\endgroup\$ – Geva Tal Dec 23 '13 at 14:04

Usually electret/condenser microphones require power to operate. These microphones are also called as capacitor microphones. There is a capacitor whose one plate will move as per the sound waves. This will cause a change in the capacitance which is equivalent to the sound waves.

In order for these microphones to work, power is required. Capacitors has rtto be charged to see the capacitance varying. These microphones are powered from the same audio line of the amplifier. If there is no power reaching the microphone, then it can't operate. Hence it draws small amount of current.

It is normal that these microphone consumes power. For any electric circuit to work, current is required. Each device you connect to your phone will consume power. Since the current consumed is 0.17mA, you won't notice a big difference in the battery life.


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