E.C.G. Schematic

[Steve_hi]

Hi. I have put this cicuit together and checked it many times and cant get it to work.
It's supposed to hook to a computer through the sound card and using a program provided by the author of the schematic show a wave form on the monitor but I cant get it to work I have gone over my circuit many times but I cant find anything wrong with it any help would be greatly appreciated.

Here is the link to the site for full details
http://www.eng.utah.edu/~jnguyen/ecg/instructions.html

 

[audioguru2]

Did you connect the ECG circuit through a 100 ohm resistor in series with a 4.7uF non-polar coupling capacitor (or two 10uF polarized elactrolytics back-to-back) to the microphone input on your sound card?
The resistor stops the last opamp from oscillating when it is driving the capacitance of a shielded cable to the sound card.

Which opamps did you use?

The schematic doesn't show connections to the power supply pins of the opamps and a supply bypass capacitor is missing.

 

[Kevin Weddle]

You might want to narrow the problem down. Many things have to go right with that setup.