Add an ear to your project with this well-designed electret microphone amplifier. This fully assembled and tested board comes with a 20 Hz–20 kHz electret microphone soldered on. For amplification, we use the Maxim MAX4466 op-amp, optimized for microphone applications. The amplifier features excellent power supply noise rejection, delivering clean audio performance with low noise and minimal distortion. This breakout is ideal for voice-related projects, audio recording or sampling, and audio-reactive applications using FFT analysis. A trimmer potentiometer on the back allows adjustable gain from 25× to 125×. At typical speaking volume (about 15 cm away), output ranges from approximately 200 mVpp (suitable for line-level inputs without clipping) up to ~1 Vpp (ideal for microcontroller ADC input). The rail-to-rail output can reach up to 5 Vpp for loud signals. To use: - Connect GND to ground and VCC to 2.4–5 VDC. - For best results, use a low-noise power supply (e.g., the 3.3 V supply on an Arduino). - Audio waveform is available at the OUT pin. - Output includes a DC bias of VCC/2 — voltage remains steady at VCC/2 when no sound is present (DC-coupled output). - If AC coupling is required, place a 100 µF capacitor between the OUT pin and the input of your device. - No capacitor is needed when connecting to audio equipment with built-in decoupling or differential inputs. - The output is not intended to drive speakers or headphones directly. An external audio amplifier is required for speaker output. - When connecting to a microcontroller ADC pin, no additional amplifier or coupling capacitor is necessary.