Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: OpAmp with same inputs

  1. Jan 30, 2010 #1
    1. The problem statement, all variables and given/known data
    Circuit:
    opamp1.jpg

    Both inputs are connected to a person's wrists (we tried it with fingers too).
    The resistors are both 1Mohm

    "What is the name of the resulting waveform?"

    3. The attempt at a solution
    All we saw is noise and something that looked like a triangle function (jagged zigzag type thing). I'm not sure we did this right and I was just wondering if this setup is called something specific that I could possible look up.
     
  2. jcsd
  3. Feb 1, 2010 #2

    berkeman

    User Avatar

    Staff: Mentor

    What do you mean connected to the wrists? One to each wrist? How did you make connection? Were you trying to get some sort of differential ECG measurement? EMG?

    If you just hard short the two inputs together in the figure shown, then you will just amplify the Input _____ Voltage by some gain? What goes in the blank, and what gain multiplies it? What output voltage would that give you approzimately?

    BTW, what are the power supply inputs for the opamp, how is it bypassed, and what is the goal of the circuit?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook