I am new to hardware experiments, although I have acceptable theoretical knowledge. My setup is:
- a signal generator
- a breadboard with an op-amp (not powered)
- an oscilloscope
The output of the generator has a splitter, one cable goes directly to the oscilloscope plotting the input (a sine wave). The second cable leaving the splitter is a crocodile clip cable. The oscilloscope has a probe.
There is this phenomenon I don't understand. When neither the probe nor the crocodile cable are attached to anything the sine wave shows correctly on the oscilloscope (I am just talking about the direct line from the generator, not the probe). When I connect the ground of the oscilloscope probe to the Vcc- of the op-amp, and the red crocodile cable to the IN+ of the op-amp, the sine wave is distorted (see photo attached).
I am sure there must be a simple answer, maybe something to do with the device impedance etc. but I just can't wrap my head around it. This prevents me from properly measuring the op-amp's output for an input sine wave.
The following schematic shows the fully connected setup. The input sine wave is still distorted, however the op amp works fine (don't have a photo, but it's constant high value when input is positive and constant low when negative)