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|Stethoscopes are not only useful for doctors, but home mechanics, exterminators, spying and any number of other uses. Standard stethoscopes provide no amplification which limits their use. This circuit uses op-amps to greatly amplify a standard stethoscope, and includes a low pass filter to remove background noise.|
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|efficient circuit. working good in all aspects|
|sir would u please mention the cost and complete details of this project please..........|
|We made the stethoscope but instead of LM386 we used LM380 and instead of TL072 we used LM381 as in another book it was written so.. but in our output while using loudspeakers the volume is too low.. we didnt do the volume control part.. we attached an led in parallel wid speaker to check if the circuit is working, the led keeps on blinking but loudspeaker output is too low. also instead of a mic we used a crystal pick-up cartridge. do we need to shield cable the 3 wires from the pick-up cartridge? please respond asap! thanks!|
|i made this project and it all is working very good .But replace this mic with mobile phone mic this is very small in size and lower in noise....................thanx|
|i have done the project.its picking up sound.leds does't match with the heartbeat sound theres lot of buzz sound .and even i have altered it and added a counter to it.it working but the beats are not matching. suggest me something please|
|i have made the ckt but its not working and i have no idea about the battery which i have made is correct or not|
|its gr8 n ckt is proper, it in workng............thnks|
|The 2 batteries are in series to provide +9V and -9V ... see the ground line in between. They will not produce +18V !!!|
|A nice project! I detected several weak points: 1. The ordinary electret microphone is not sensitive enough to < 100 Hz where important heart sounds can be heard through a normal stethoscope. 2. Using two 9V batteries makes the instrument heavy, and using LM386 is not good due to a high current consumption. A headphone needs only a couple of mW, not 3 Watts LM386 can generate. 3. If "Stereo headphones" are used, only a mono response can be expected. Why not add another channel, microphone to earphone? 4. I would recommend using only one 9V battery and TL082 opamps. Does anyone know where to find a good small microphone with a good <100 Hz response?|
|sir mic is working but can't picking the heart beats.could you suggest other mic|
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