Categories: Pre Amplifier

Simple Audio Pre-Amplifier

This is a simple audio pre-amplifier circuit using single transistor 2N3904.

This easy circuit provides good gain to weak audio signals such as electret microphone. Use it in front of an RF oscillator to make an RF transmitter that’s very sensitive to sound. Power supply used for this circuit is wide range from 3VDC to 9VDC, you may choice the middle range about 6VDC to minimize the risk, safety purpose 🙂

Components List:

R1 = 10k
R2 = 100k
R3 = 10k
C1 = 0.1uf or if you prefer 104 or 100n
C2 = 0.1uf or if you prefer 104 or 100n
Q1 = 2N3904
MIC1 = a common electret microphone
circuit schematic

View Comments

  • can I use this circuit with the output as an analog input to an Arduino ? thanks in advance for the reply ....

  • hi dir i bult mic pre with lm 358 1k 100k feedbeak risister atach with pc 9volt powersupply his rang is vare low but iwant rang 1 feet whate i do my mic rang 1 feet chang feedback risistens or in put resistence or bult other bufer

  • Hi can u plz plz plz help me,i own a nokia phone that has a very low sound volume.so i want to make a very tiny sound amp that i can attatch to a very small speaker so i can hear louder and better sound quality.plz respond so i know if this is possible thanks

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