Using TLC251Microphone preamplifier Wiring diagram Schematic

This is an IC Using TLC251Microphone preamplifier Circuit Diagram. A microphone preamplifier using: om CMOS op amp with its own battery, is small enough to be placed in a case of small microphone. The amplifier operates from a 1.5V battery cathode mercury low supply currents. This preamp will operate at very low power and maintain a reasonable frequency response as well. 

 Microphone preamplifier Circuit Diagram

The TLC251 is operating in low bias (operating at 1.5 V) draws a supply current of only 10 and has a year - frequency response of 3 dB 27 Hz to 4.8 kHz. With 8-pin grounded, which is designated as the polarization state high limit increases above 25 kHz. Supply current is only - 30 pA under these conditions.

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LA3161 Stereo Preamplifier Circuit

LA3161 is an integrated 2 channel pre-amplifier meant for car stereo applications. The LA3161 contains a built in voltage regulator that plays an excellent role in improving ripple rejection . The IC needs minimum number of external components and the noise level is extremely low. The IC has high input impedance (around 100K) and is available in an 8 pin SIL package.

In the circuit each of the built in amplifier section are used. Capacitors C8 and C9 are input coupling capacitors. Capacitors C3 & C6 are noise filter capacitors. The lower cut-off frequency depends on the value of C3 and C6 network comprising of components R1, R2 & C1 defines the frequency characteristics of left channel and the network consisting of R3, R4 &C2 defines the frequency characteristics of the correct channel. C4 and C5 are output coupling capacitors. C7 is the power supply filter capacitor and it should be connected as close as possible to the power input pin (pin 4) of the IC. This IC doesn’t have short circuit protection, and short between pins may cause damage. C10 and C11 are meant for preventing radio interference, interference from engines etc.

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