Collection Schematic

Note:

• variable resistor of R5 to adjust the gain of op-amplifier IC LM358.
• The LM358 has two op-amp module, you may build stereo audio pre-amplifier using single LM358.

Component list of simple preamp mic circuit:

R1, R3, R4 : 10K
R2 : 1K
R5 : 100K-1M Potensiometer
C1 : 0.1uF
C2 : 4.7uF/16V
IC1 : LM358 dual op-amplifier
Mic : Electret Microphone 

Here the schematic diagram of mic preamplifier which build based on operational amplifier TC251. The TLC251 is operating in low bias. The schema works with only 1.5 V supply draws electric current of only 10 mA, so the battery operation will be prefered. Circuit frequency response is 3dB, 27 Hz to 4.8 kHz.



Frequency Response:


The TLC251 are low-cost, low-power programmable operational amplifiers designed to operate with single or dual power supplies. Because the input common-mode range extends to the negative rail and the power consumption is very low, this chip is ideally suited for battery-powered or energy-conserving applications. A bias-select pin can be used to program one of three ac performance and power-dissipation levels to suit the application. The series features operation down to a 1.4V supply and is stable at unity gain.

Download the TLC251 datasheet document from the following link:
» Download link