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  1. R

    Change in resistance of electret microphone with sound

    Hi, I read electret microphone changes its resistance according to sound applied. the resistance is proportional to loudness of sound. can anyone provide me some information about it? I want to calculate resistance for different sounds? I don't have oscilloscope. is there any information on...
  2. R

    Electret microphone is giving unsual resistance

    do you mean, I should add a timer 555?
  3. R

    Electret microphone is giving unsual resistance

    if I deactivate second flip flop, short duration of pulse will work?
  4. R

    Electret microphone is giving unsual resistance

    thanks a lot audioguru. I will create a new circuit and test it. but, you also told that 4027 ic connections are wrong. I copied as it is from a book. what you found wrong in it?
  5. R

    Electret microphone is giving unsual resistance

    disable means not adding any connection to second opamp?
  6. R

    Electret microphone is giving unsual resistance

    thanks audioguru. I tried to get this IC but unfortunately it is unavailable in my area. Can I use any ic like LM358 or something else?
  7. R

    Electret microphone is giving unsual resistance

    hi, thanks for the information. I want this circuit to be controlled by 9v battery. what opamp do you recommend for this voltage? thanks
  8. R

    Electret microphone is giving unsual resistance

    Hi, I am trying to make a clap switch, schematic is given below: I am using 9v battery but it is giving 7.55v currently. When I am measuring the voltage in microphone voltage divider part. it is coming 6.7v. which is strange because If i calculate the resistance for the voltage then the...
  9. R

    TDA2030 amplification is very less

    hi, none of the methods are working. One question: can it be because I am using trimmer preset in place of rotary potentiometer which is present in the circuitry of TDA2030A IC? thanks
  10. R

    TDA2030 amplification is very less

    Hi, I am trying to amplify the sound generated by timer 555 circuit with TDA2030A. But, the amplification is very less, hardly audible. Please check the circuit below: TDA2030A amplification circuit is taken from datasheet. I didn't placed the capacitor (please check the capacitor outlined...
  11. R

    UM66 is not giving full tone

    I watched on youtube.
  12. R

    UM66 is not giving full tone

    because I thought it to be universal. I think UM66 is available throughout the world.
  13. R

    UM66 is not giving full tone

    thanks duke37. it is a good idea. Actually, the whole confusion occurred because I am in India. I checked on net. I realized that there is a transformer installed in houses in western countries to get 12 to 16v. Here, there is no such thing. Thats why I was confused about what you are asking...
  14. R

    UM66 is not giving full tone

    it was my mistake. I did't realized that amplifier needs voltage too. when power is off, it cannot amplify the sound.
  15. R

    UM66 is not giving full tone

    sorry if you think I am arrogant. I am just a beginner with little knowledge, I am no match for knowledge you have. I am only somewhat confused. I was just trying something on my own.
  16. R

    UM66 is not giving full tone

    ok. I got it. it needs a continuous supply to the amplifier. I will add a 12v adapter and switch on safe side. thanks a lot.
  17. R

    UM66 is not giving full tone

    I added two capacitors , you can see them below in schematic in red color. But, it is not working yet.
  18. R

    UM66 is not giving full tone

    the transformer is inside a box with the circuit. it is added inside drawing room. so there is no chance than it can get wet. the switch is on main gate outside.
  19. R

    UM66 is not giving full tone

    I think there is some misunderstanding here. by bell push, I mean 230v 6A bell button. Such button is given below
  20. R

    UM66 is not giving full tone

    yes, the bell push is on the main side of the center tapped transformer. tone generator is IC BT66 ( Q1) which gets 3.9v through zener diode (Zn) sorry, I didn't got proper symbol on my schematic software, so I used a transistor symbol.
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