Hey all,

I have been thinking about a circuit that uses a range selection similar to a volt meter that is done with window comparators. I don't have it drawn out i'm just thinking theory at this point. Now, i would assume that you may have trouble with outputs becoming intermittent or oscillating as the thresholds are approached. I have read that hysteresis is a possible solution to this...How would this be implemented in a window comparator or say that LM339 circuit that works like a mini bar graph? I understand the concept of hysteresis, which I believe is a voltage gap between thresholds to stabilize and almost "toggle" them so to speak. I just don't know how to use them with more than a single comparator.

Would this also be a viable possible solution for a situation where voltages were compared on a microvolt level? As in, the comparator is off at 2.000001V and on at 2.000002V? I know the comparators would have to be very precise and noise would also play a big concern at that point.

 

If you post the window comparator circuit, we may be able to suggest a way to add hysteresis.

 

The design of the hysteresis circuit must include and account for the input offset voltage of the comparator. Thus, one microvolt sensing requires a high precision comparator.

 

Doing the math for 1 microvolt is easy enough. Doing it in reality is a much more difficult job.
You probably don't need that kind of quality. Reconsider your requirements.