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I’ve been working on a threshold-detection circuit using a standard low-power comparator, but I’m running into an annoying issue with oscillation right at the trip point. I’ve added a modest amount of hysteresis using a feedback resistor, but it doesn't seem to be fully resolving the "chatter" when the input signal is slow-moving.

Analyzing the Hysteresis Thresholds The input signal is coming from a sensor with a relatively high source impedance. I suspect the oscillation is being triggered by a combination of the input bias current and some stray feedback noise on the PCB.

Determining Hysteresis Width: How do you guys calculate the optimal hysteresis for low-power applications? I want to avoid adding too much current draw, but I need enough of a "buffer" to prevent the output from toggling rapidly. Filtering Strategies: Would adding a small capacitor in parallel with the feedback resistor help stabilize the switching, or does that create too much of a delay in the output response? Component Influence I've modeled the basic topology in CircuitLab, but the ideal comparator models don't really capture the propagation delay variations that seem to be causing this jitter. Has anyone found a better way to simulate real-world noise sensitivity in these basic threshold circuits?

Environmental impact on testing To complicate things, the weather in my area has been extremely unstable lately. We’re dealing with major pressure drops and high humidity, and I’ve noticed my test bench is surprisingly sensitive to these changes.

The humidity seems to be slightly affecting the leakage paths on the board, which is drifting my reference voltage just enough to make the threshold inconsistent. I’ve been constantly recalibrating the circuit every few hours because the ambient conditions are shifting. It’s definitely a reminder that high-precision sensing is as much about controlling the environment as it is about the circuit design itself.

Seeking advice If anyone has experience with stabilizing comparator circuits in high-impedance, high-humidity environments, I’d love to hear your approach. Are there specific layout techniques or guarding strategies you use to isolate the reference node from these environmental variables?

Any advice or suggestions would be greatly appreciated. https://thoitiethomnay.org/