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    Electronic Stethoscope 2

    Dear Audioguru, You were right when u said that the voltages are missing. I'm using DC power supply. I can't seperate the positive voltage and the negative voltage. From the DC male jack to the female jack, with a multimeter, i can get both the +ve and -ve voltage. But once i connect the two...
  2. S

    Electronic Stethoscope 2

    Dear Audioguru, What shoud i do now? If my PCB connections are correct, what maybe wrong? If the Microcontroller are faulty, would it cause the different voltages? Is it ok if i supplied more than 9 Vs? how to check if my ICs are faulty?
  3. S

    Electronic Stethoscope 2

    Dear AUDIoguru, Thanx for the input. These are my measured voltage: TL072 Pin 4 = -7.2V           Pin 6 = -0.08V           pIn 7 = -0.12V           pIn 8 = +0.07V LM386 Pin 1 = +1.5v           Pin 5 = +1.9V           Pin 6 = +2.7V           Pin 7 = +0.2V           Pin 8 = +0.2V UA741...
  4. S

    Electronic Stethoscope 2

    Dear Audioguru, Thank you for the reply. Can you draw the schematic of the extra circuit? I'm not sure how to connect the two diffeerent values to the main PCB and with a switching function. Hope to hear from you soon. Thanx.
  5. S

    Electronic Stethoscope 2

    Dear Audiuguru, 1) How do i know if i'm using a linear trimpot? 2) Can i still add the 3.3k resistor at pin 3 to gnd of U5 if it is already a linear trimpot? 3) Are there any other resistors on this circuit that i can change to trim pots in order to    change its functions/variability? 4)...
  6. S

    Electronic Stethoscope 2

    these are the pics of my PCB. the batts are replaced by DC supply. thank you for helping.
  7. S

    Electronic Stethoscope 2

    Dear Audioguru, Is it ok if i use a 9V DC supplY? Used up many batts during the process of trials.. Cant afford too many.. =P I am also using a 6 pole switch... where only 4 are being used. i use it to seperate the positive n negative voltage.  is it ok? Am fabricating a new PCB in a few daes...
  8. S

    Electronic Stethoscope 2

    The DC voltage for the points : pin1 U1 = 6.9V, pin7 u1 = 7.3V Pin6 U4 =8+V , pin5 U5 = 7+V
  9. S

    Electronic Stethoscope 2

    hi again, i have problem with the circuit i just bulit. the batt turns very hot in like 15 seconds right after i connect the batteries. can help me solve this problem? wat r the possible errors? pls help.. thanx.
  10. S

    Electronic Stethoscope 2

    dear audioguru... i dun think its the batt.... it still has 7V+.. =) volume min = LED flashes fast volume max = LED blinks steadily.... blue then red... blue then red.... (tick-tocks) i attached a speaker... theres sound... no howling..... (ticks tocks) i attached headphones... very loud...
  11. S

    Electronic Stethoscope 2

    hey.. thanx audioguru.. now it works... meaning there is sound output.... but theres a contanst *tick-tock* sound when the power is turned on. meaning.. my led will blink twice evry other second even without me talking into the mic,... when i touch the mic... it will have sound output... but...
  12. S

    Electronic Stethoscope 2

    mr audioguru... Bell (20-200 Hz) - Diaphragm (100-500 Hz) - Extended Range (20-1000 Hz) these are the ranges that a normal stethoscope can or should detect... can this circuit be likewise? wat changes needed to be done to the circuit to achieve this modes...?? wat is the frequency range of...
  13. S

    Electronic Stethoscope 2

    audioguru......the speaker has +ve n -ve.... how do i connect it? the positive to pin 5 of lm386? the negative to ground? im still having trouble connecting the power supply... =( thanx..
  14. S

    Electronic Stethoscope 2

    hi again.. sorry to disturb u... if i wanna connect a speaker to the circuit.. how do i do it? will the led cont to light up when i turn the swith to off? its contant blinking when i switch it off.. till i unplugged the batt connection only it will slowly fade off... thanx...
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    Electronic Stethoscope 2

    heyz.. audioguru.... had been working on ur circuit.... i did use a function generator to input some signals.. the output was quite ok.. not much noises.. i cant hear anything using the mic though.. maybe i burned it while soldering... hehe.. anywaes.. do u have the circuit diagram in .ckt...
  16. S

    Electronic Stethoscope

    heyz... im currently working on my final year project.... it wld be really helpful if anyone cld tell me which is the finalised circuit that i shld follow......something that will work... is it the stethoscope 2 that audioguru posted? and.. if i wld like to connect the entire circuit to the...
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