Speech amplifier circuit.

admin April 7, 2010 10 Comments

Description.
This circuit given here can be housed in the box containing the speaker to form a handy microphone amplifier.The device can be used by teachers,guides,lecturers etc for speaking in a crowdy or noisy environment.

The circuit is designed base on the audio power amplifier IC TDA 7052.The IC can deliver a maximum power output of 1.2 W at a 6V supply.The audio signal from the microphone is pre amplified by the amplifier based on Q1 (BC 547) and give to the input of IC1 (pin 2).The POTR5  acts as a volume control.The capacitor C3 is used to bye pass the upper frequencies in order to avoid the Larsen’s effect(the microphone picking up speaker output to cause howls).

Circuit diagram with Parts list. 

speech-amplifier-circuit.JPG

Notes. 

  • Use a 8 Ohm speaker or two 4 Ohm speakers in series as load.
  • Assemble the circuit on a good quality PCB or common board.
  • A 6V SMF battery is my choice for powering the circuit.
  • Switch S1 can be used as a ON/OFF switch.
Comments
  • amaan
    April 30, 2015

    Can we use 20 k pot

  • sayantan
    September 12, 2013

    if we attach a simple cndnsr mic(without pre-amp) at the input wl it amplify da voice spokn?plz rply m wtng.

  • ashwani
    June 8, 2013

    I am a class 12 student. I have a single speaker of 4 OM 6 W. I want to sound it with a mobile phone and with 220v domestic current. Will you help me to suggest which component should i purchase, and how it should be assembled .
    Thank you for help

  • DAVID M. AGBATTA
    October 16, 2012

    Please i need the power supply circuit of speech amplifier box. Thankz

  • Aboobakal
    March 2, 2011

    i want to make an amplifier so plz help with a simmple circuit

  • samuel
    June 15, 2009

    plz i want to kwon the scope and features of speech amplifier box.thankz

  • subin
    February 25, 2009

    does this work properly??????????means if you say something in a low voice will it amplify and produce a large output????

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