Video summary

How to use an electret condenser microphone in your electronic circuit

Main summary

Key takeaways

Technology

Summary (Technology + Circuit/Build + Key Measurements)

  • Electret condenser microphone overview: The video discusses electret condenser microphones (capsule mics), focusing on how to power and interface one in an electronics circuit.
  • Part/source example: References an electret mic capsule model labeled “6050” (with a corresponding “6050 PDF” datasheet reference). The presenter also mentions purchasing ~30 pieces from Amazon at low cost.

Power requirements (from the datasheet)

  • Maximum supply voltage: ≤ 10 V (The capsule includes internal FET/biasing circuitry, so it must be powered.)

  • Example supply used: 9 V battery, which is within the datasheet limit.

Bias/load resistor (RL)

  • The datasheet is used to set the bias with:
    • RL = 2.2 kΩ

AC coupling capacitor

  • A 1 µF capacitor is used in series before the output to remove DC from the mic/bias network.
  • Expected behavior explained by the presenter:
    • Before the capacitor: you should see DC
    • After the capacitor: you should not see DC

Reference circuit structure

  • Mic capsule pins: Positive/top and negative/bottom are identified.
  • Signal path:
    • The mic negative goes into the bias/load network with RL
    • The 1 µF capacitor then provides AC coupling
  • Supply: The video uses VS = 9 V and GND appropriately.

Building/measurement with an oscilloscope

  • The presenter builds the circuit on a breadboard with jumpers and connects a 9 V battery.
  • They use an oscilloscope (noted as a low-cost ~$20 device) to view waveforms.
  • Test 1: DC coupling first
    • With DC coupling enabled, the waveform shows a large DC offset.
    • After adjusting oscilloscope vertical sensitivity, they observe the DC level is around ~7.5 V (as read on the scale).
  • Test 2: AC coupling / capacitor behavior
    • After switching to AC coupling, the oscilloscope no longer shows DC and instead shows microphone activity.
    • They whistle and/or tap to confirm the mic output is being captured.

Observed microphone output amplitude

  • With oscilloscope settings around 10 mV/div, the measured audio appears to be roughly ~20 mV peak-to-peak (pp).

Conclusion of the tutorial

  • The presenter does not add an amplifier stage.
  • They note that the raw output is small and you would likely need an amplifier (e.g., a common-emitter amplifier) to make it more usable.
  • Overall purpose: primarily to demonstrate how to use an electret condenser microphone in a basic circuit.

Key “How-to” Takeaways / Checklist

  • Power the electret mic with ≤ 10 V (example uses 9 V).
  • Use RL = 2.2 kΩ as the bias/load resistor.
  • Use a 1 µF coupling capacitor to remove DC and pass the audio waveform.
  • Verify with an oscilloscope:
    • With DC coupling, you should see DC before/around the coupling capacitor
    • With AC coupling (or measuring after the capacitor), DC should disappear while audio remains
  • Expect modest raw output (about ~20 mVpp here) and consider amplification if needed.

Main Speakers/Sources

  • Speaker/Presenter: Not named in the subtitles.
  • Source referenced: The microphone datasheet for the capsule/mic model labeled “6050” (plus the Amazon-purchased microphone listing).

Original video