Electret microphone amplifier circuit using transistors

This electret microphone amplifier circuit is designed using common electronic components . This microphone amplifier circuit uses an electret microphone capsule, but can be an dynamic microphone, which have a low resistance. This circuit requires a supply voltage between 5 and 10 volts, is recommended to use a supply voltage of 9 volts DC . Since the circuit has a very low power consumption (about 1.5m), circuit can be powered using a 9 volt battery. The values for R1, C3 and R8 are for Philips LBC1055/00 electret capsule.
Amplification depends on the ratio R7/R3, is greater than 100.