Electronic Stethoscope

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.


PARTS:-


R1    1    10K 1/4W Resistor  
R2    1    2.2K 1/4W Resistor  
R4    1    47K 1/4W Resistor  
R5, R6, R7    3    33K 1/4W Resistor  
R8    1    56K 1/4W Resistor  
R10    1    4.7K 1/4W Resistor  
R11    1    2.2K to 10K Audio Taper Pot  
R12    1    330K 1/4W Resistor  
R13, R15, R16    3    1K 1/4W Resistor  
R14    1    3.9 Ohm 1/4W Resistor  
C1, C8    2    470uF 16V Electrolytic Capacitor  
C2    1    4.7uF 16V Electrolytic Capacitor  
C3, C4    2    0.047uF 50V Metalized Plastic Film Capacitor  
C5    1    0.1uF 50V Ceramic Disc Capacitor  
C6, C7    2    1000uF 16V Electrolytic Capacitor  
U1    1    TL072 Low Noise Dual Op-Amp  
U4    1    741 Op-Amp  
U5    1    LM386 Audio Power Amp  
MIC    1    Two Wire Electret Microphone  
J1    1    1/8" Stereo Headphone Jack  
Batt1, Batt2    2    9V Alkaline Battery  
LED    1    Red/Green Dual Colour Two Wire LED  
SW    1    DPST Switch  
MISC    1    Stethoscope head or jar lid, rubber sleeve for microphone, board, wire, battery clips, knob for R11