I have built my first ever OP-AMP RC Multivibrator using the schematic above. It produces a square wave, but it is somewhat problematic. The square wave has a duty cycle of only ~25%, and has a non-zero base value. To inspect this, I put a probe up to the points on the schematic labelled PROBE + and PROBE -. This is what my scope read:
What seems to be happening here is that the capacitor seems to be both charging and discharging through the resistor. This is problematic because the duty cycle also based on the capacitor discharging to a non-zero value.
Here's a picture of the output (yellow) compared to VCC (blue).
The second problem is that the capacitor is charging to only 350mV, which results in a 350mV peak. Is this supposed to be the case? how would I amplify this? My first Idea was to hook up the output to a second OP-AMPs inverted in, and the positive rail to the non-inverting in, which should produce the inversion of the wave. I would then hook that up to a NOT gate to get the original waveform. The result of hooking this up to the OP-OP AMP is Shown above. The yellow line is the output of the multivibrating OP-AMP, the blue line is the result of the secondary OP-AMP. As you can see, the secondary input messes with the first output signal. I'm not sure why.
Any help with this would be appreciated.
OP-AMP datasheet: http://www.ti.com/lit/ds/symlink/ne5532.pdf