The op amp circuit is oscillating, please help from experts.
The problem is that when the op amp is not connected to the subsequent stage comparator, the output waveform of the op amp is correct, which is probably the following waveform
But after connecting the comparator, the output of the op amp becomes an oscillating signal, and the frequency is also in the same order of magnitude as the above frequency. My brother speculates that the op amp is oscillating, but I have not been able to find a suitable way to solve this problem. I hope you can talk about your opinions on this issue. I am very grateful.
Marquis Posted on October 19, 2020
Is the power decoupling of the op amp not done well?
Ciaran Posted on October 19, 2020
It is recommended that you add a resistance of about 1M from the negative terminal of the comparator to the output.
It should solve your problem.
Gillian Posted on October 19, 2020
Try adding a 100K resistor from the negative terminal to the ground?
Terrence Posted on October 19, 2020
The oscillation frequency is not very high, it should not be an impedance matching problem, just change it to a hysteresis comparator.
