mic audio circuit


Posted on Feb 5, 2014

It can be used as part of intercoms, walkie-talkies, low-power transmitters, and packet radio receivers. Transistors T1 and T2 form the mic preamplifier. Resistor R1 provi


mic audio circuit
Click here to download the full size of the above Circuit.

des the necessary bias for the condenser mic while preset VR1 functions as gain control for varying its gain. In order to increase the audio power, the low-level audio output from the preamplifier stage is coupled via coupling capacitor C7 to the audio power amplifier built around BEL1895 IC. BEL1895 is a monolithic audio power amplifier IC designed specifically for sensitive AM radio applications that delivers 1 watt into 4 ohms at 6V power supply voltage. It exhibits low distortion and noise and operates over 3V-9V supply voltage, which makes it ideal for battery operation. A turn-on pop reduction circuit prevents thud when the power supply is switched on. Coupling capacitor C7 determines low-frequency response of the amplifier. Capacitor C9 acts as the ripple-rejection filter. C13 couples the output available at pin 1 to the loudspeaker. R15-C13 combination acts as the damping circuit for output oscillations. Capacitor C12 provides the boot strapping function. This circuit is suitable for low-power HAM radio transmitters to supply the necessary audio power for modulation. With simple modifications it can also be used in intercom circuits.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Motorized Remote control with ATMEGA328
    2 Kw flasher with photoelectric control
    Logic-pulser
    Accurate-ramp-generator
    synchronized sawtooth
    arduino based thermorbios weather station receiver
    IR to RF converter circuit
    Video Clock and Message Generator
    Telephone Ring Generator Using Small Power Transformer
    ELECTRONIC COMBINATION LOCK
    FREQUENCY COUNTER PREAMP



    Top