How to test a capacitive microphone
For most cheap capacitive microphones (which include the built-in amplifier, and this is probably your case, as you call it a "mini microphone used in phones") the circuit below should work. Typical Vcc should be +3.3V or +5V (do you have any documentation of your microphone, stating what is the acceptable power supply voltage?).







simulate this circuit &ndash; Schematic created using CircuitLab