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  1. Emad1

    Electronic Stethoscope 2

    There is no distortion but just a sound like air or shshshshshshsh. the components around U1 are not the same like the original nor the corrected circuit . I had a diffirent circuit for U1 that Ill post it after I drow it . many many thanx .
  2. Emad1

    Electronic Stethoscope

    Audiguru. Iforgot to tell you that I took the LM358 from the shop and when Iwent home I found it KIA358 and I used it. This IC doesnt need a ground and so I used a single battery, just positive and negative
  3. Emad1

    Electronic Stethoscope

    hi Audiguru. I had no TLO71 in my area so I tried to use to use just one IC as apreamplifier and another one as an amplifier------- Just two . the preamplifier is LM358 and then the amplifier is the LM386 as that in your corrected circuit-------I hear my heart beats very well------- Ijust need...
  4. Emad1

    Electronic Stethoscope

    Hi audaguru. LM386 is the U1 or U4. Are C3 andR7 connected to pin6 ofU2 or just connected to each other . Many many thanx for your help and your being patient with me .
  5. Emad1

    Electronic Stethoscope

    Hi Audaguru . What is the value of R16 in the corrected circuit. How many ohms or kiloes?-------
  6. Emad1

    Electronic Stethoscope

    Hi all . I constructed the corrected circuit and I have good amplification when I make clicks with my tongue.,but heart sounds are distorted . there are many cracles and crepitaions with the soundto the extent that no heart sond could be heared when increasing the volume. I used anon shielded...
  7. Emad1

    Electronic Stethoscope

    MP thank you . Iknow you are right but because I need this circuit Ill try the corrected schematic.I hope it works well.I hpe i have another circuit for the same reason,so if you have another stethoscope circuit diagram plz tell me.Thank you again
  8. Emad1

    Electronic Stethoscope

    thank you audiguru and moderator--------I shall make the corrected circuit from the bigining. it is more simple.I hope it functions will
  9. Emad1

    Electronic Stethoscope

    i have put 2.2k variable risistance instead of the 2.5k variable R simply because i did not find the 2.5k-------I made clicks with my tongue near the mike and i hear it as sharp clicks,so Ithought the circuit is good but it wasnt--------- sounds other than the clicks are not...
  10. Emad1

    Electronic Stethoscope

    yes ,I mean the original schematic-----thank you
  11. Emad1

    Electronic Stethoscope

    Hi--I made the 1st schematic ----it acts well------- i put the pin 4 of U5 to negative voltage ,also i put 2 light diodes in opposite instead of the bipolar diod as i did not find it ------and a variable resistance of 2.2k ------the circuit is working fine -----now I just need a cone to compare...
  12. Emad1

    Electronic Stethoscope

    [first thank u for the circuit and the forum-----i am a physition and just do circuits as it is---so forgive me for my silly qwustians and my bad languitch as i am egyptian--- i ask about connecting the common earth and the negative volt----- are they connected together??? and if not how can i...
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