Blue Board Breakout Adjustable Gain Compatible With Arduino 6 Pcs Max4466 Using introduction: Connect GND to ground, VCC to 2.4-5VDC. The audio waveform will come out of the OUT pin. The output will have a DC bias of VCC/2 so when its perfectly quiet, the voltage will be a steady VCC/2 volts (it is DC coupled). If the audio equipment you're using requires AC coupled audio, place a 100uF capacitor between the output pin and the input of your device. If you're connecting to an audio amplifier that has differential inputs or includes decoupling capacitors, the 100uF cap is not required. The output pin is not designed to drive speakers or anything but the smallest in-ear headphones- you'll need an audio amplifier (such as 3.7W stereo amp) If you want to connect the amp directly to speakers. If you're connecting to a microcontroller pin, you don't need an amplifier or decoupling capacitor - connect the OUT pin directly to the microcontroller ADC pin. For audio-reactive projects, we suggest using an FFT driver library which can take the audio input and 'translate' it into frequencies. Package Included: 2* MAX4466 Electret Microphone Amplifier Module Application scenarios: cellular phones, repeating sound device, earphones, hearing aids, microphone preamplifiers, portable computers, voice recognition systems, etc. This fully assembled and tested board comes with a 20-20KHz electret microphone soldered on. Easy to use:The board comes with a 20-20KHz electret microphone soldered on Using the MAX4466, an op-amp specifically designed for amplifier; for the best performance, use the "quietest" supply available (on an for Arduino, this would be the 3.3V supply);the amplifier has excellent power supply noise rejection Parameters: power supply voltage: +2.4V to +5.5V (can be compatible with STM, Raspberry Pi and other development board motherboards); Power supply rejection ratio: 112dB; Common mode rejection ratio: 126dB; AVOL: 125dB (RL = 100k?) rail-to-rail output; Quiescent power supply current: 24?A; Gain bandwidth: 600kHz Size:20.8MM*13.8MM*7.5MM This breakout board is best used for projects such as voice changers, audio recordingmpling, and audio-reactive or DIY projects that use FFT